chvymudin3388
1/2 ton status
k i have 2 twelves in an enclosre i like it but want to get a band pass. whats better bandpass or enclosed
CK5
Register an account today to become a member! Once signed in, you'll be able to participate on this site by adding your own topics and posts, as well as connect with other members.
ok stereo guys
- Thread starter chvymudin3388
- Start date
hunterguy86
1/2 ton status
Enclosed. its eaiser to build. It will sound a lot better to.
what kind of subs? what truck? how much room u got to work w/.
If it were me I would go ported and tune to about 30-35 hz. Ported boxes are very efficent. u can push larger subs w/ a little bit smaller amp too.
what kind of subs? what truck? how much room u got to work w/.
If it were me I would go ported and tune to about 30-35 hz. Ported boxes are very efficent. u can push larger subs w/ a little bit smaller amp too.
chvymudin3388
1/2 ton status
so what i need to do is port it by using pvc right that stix so far into the box right
i got 2 twelve in sony xplod not top of the line but they harder then almost ne ones at my school lol
i got 2 twelve in sony xplod not top of the line but they harder then almost ne ones at my school lol
Depends on the subs I like sealed boxes but I always run good subs (ported will give you more and deeper bass but I prefer the tighter sound) Banpass boxes are junk with awsome subs but make a cheap sub sound alot better
chevyin
1/2 ton status
Bandpass enclosures have a relatively narrow passband frequency range, but their efficiency within this range is very high. Bandpass boxes can be difficult/complex to build and properly blend into your system, and are the largest of the three main enclosure types. Prefab bandpass boxes almost never get it right and end up with an extremely narrow passband that becomes the infamous one note wonder. A properly built bandpass can however sound very good.
Ported enclosures are the second largest enclosure type of the three. Ported boxes can sound very musical, or be very one note oriented. Lower tuning (usually low 30's) gives a more musical response with lower extension, while higher tuning (45-70hz) is used for SPL purposes, but gives poor response with music. The ported (also called vented) enclosure is less efficient than bandpass, but more efficient than sealed boxes. Their efficiency is highly dependant on the enclosure's tuning frequency, and the frequency of the signal material.
Sealed enclosures are the smallest of the three, they also tend to give the widest usuable frequency range, but are the least efficient.
Sealed is generally the preferred enclosure type for soundquality installs, ported is generally used for 'street beater' systems (loud but still musical) while bandpass is usually preferred by those people wanting a cool window in their box.
Bandpass is a type of enclosure, so I do not know how to reply to your poll (bandpass or 'enclosed'). I will say I do not recommend bandpass unless you are skilled at building enclosures and really know what you're doing. If its your first DIY box, build it sealed. If buying, go sealed or ported, which ever fits your needs better.
edit: btw there is an audio board
Ported enclosures are the second largest enclosure type of the three. Ported boxes can sound very musical, or be very one note oriented. Lower tuning (usually low 30's) gives a more musical response with lower extension, while higher tuning (45-70hz) is used for SPL purposes, but gives poor response with music. The ported (also called vented) enclosure is less efficient than bandpass, but more efficient than sealed boxes. Their efficiency is highly dependant on the enclosure's tuning frequency, and the frequency of the signal material.
Sealed enclosures are the smallest of the three, they also tend to give the widest usuable frequency range, but are the least efficient.
Sealed is generally the preferred enclosure type for soundquality installs, ported is generally used for 'street beater' systems (loud but still musical) while bandpass is usually preferred by those people wanting a cool window in their box.
Bandpass is a type of enclosure, so I do not know how to reply to your poll (bandpass or 'enclosed'). I will say I do not recommend bandpass unless you are skilled at building enclosures and really know what you're doing. If its your first DIY box, build it sealed. If buying, go sealed or ported, which ever fits your needs better.
edit: btw there is an audio board
Leper
1/2 ton status
The kind of music you listen too will determine what kind of enclosure you need.
I don't think I would put an xplode speaker in a ported box. I dont think the voicecoil can handle the full extension of the speaker without distorting. Sealed, small box a little overpowered is my choice.
I don't think I would put an xplode speaker in a ported box. I dont think the voicecoil can handle the full extension of the speaker without distorting. Sealed, small box a little overpowered is my choice.
BozoWise
1/2 ton status
chevyin said:Bandpass enclosures have a relatively narrow passband frequency range, but their efficiency within this range is very high. Bandpass boxes can be difficult/complex to build and properly blend into your system, and are the largest of the three main enclosure types. Prefab bandpass boxes almost never get it right and end up with an extremely narrow passband that becomes the infamous one note wonder. A properly built bandpass can however sound very good.
Ported enclosures are the second largest enclosure type of the three. Ported boxes can sound very musical, or be very one note oriented. Lower tuning (usually low 30's) gives a more musical response with lower extension, while higher tuning (45-70hz) is used for SPL purposes, but gives poor response with music. The ported (also called vented) enclosure is less efficient than bandpass, but more efficient than sealed boxes. Their efficiency is highly dependant on the enclosure's tuning frequency, and the frequency of the signal material.
Sealed enclosures are the smallest of the three, they also tend to give the widest usuable frequency range, but are the least efficient.
Sealed is generally the preferred enclosure type for soundquality installs, ported is generally used for 'street beater' systems (loud but still musical) while bandpass is usually preferred by those people wanting a cool window in their box.
Bandpass is a type of enclosure, so I do not know how to reply to your poll (bandpass or 'enclosed'). I will say I do not recommend bandpass unless you are skilled at building enclosures and really know what you're doing. If its your first DIY box, build it sealed. If buying, go sealed or ported, which ever fits your needs better.
edit: btw there is an audio board
Where were you when I needed employees at my audio shop?
X2 this is a great reply. If you do not have the technical information for the specific sub, do not attempt to build an encolsure in anything but sealed form which is 1.15cu per sub on the xplodes. You will do more damage to the subs then anything. A sealed box is forgiving because of the backpressure on the sub where any of the ported enclosures will have less backpressure thus greater chance of sub overexcursion. Do not use PVC for the port as you will get a port whine from the air traveling over the rough lip of the box. I prefer a slot port design when building enclosures but Sony's website does not provide me with enough information to give you the specs. All they list is that a ported enclosure should be .82cu per sub (there is no mention of actual specs nor ported cu)
chevyin
1/2 ton status
Ported/vented boxes actually resist cone motion more than sealed boxes. Believe it or not, its true. What Im getting at is while cone motion within a vented system is largely frequency based, generally speaking you get less cone motion from ported box systems than from sealed, let me explain...
Sealed boxes resist cone motion in the obvious way, a 'cushion' of air provided by the sealed space. As the cone moves out from the box, a low pressure zone is created inside the box (volume inside box expands, amount of air molecules does not.... low pressure zone) and thus the higher air pressure outside the box/cone resists further cone motion. As the cone moves in, the opposite hhapens. The air in the box is compressed, creating a high pressure zone, thus putting force on the cone to move back out. This force always resists the cone's motion and tries to set it back to the home position. This creates the suspension cushion desired to give the right response desired from the subwoofer system.
Ported boxes work a bit differently. Obviously there is no sealed air cushion like the above type, the resistance comes from the port itself. As the cone moves in and out, its forcing air in and out through the port. The diameter and length of the port determine how much air can pass through it, and how much resistance it places on the cone's motion (which affects the enclosure's tuning frequency). Go jog around the block while breathing through a straw. The straw creates a resistance to your breathing due to being smaller than the needed space for the air to pass in and out freely (with no resistance). The diameter and length of the straw affect how much resistance it puts on the force pushing the air through it. The same thing goes for enclosure ports.
The advantage you get from ported boxes is the use of those backwaves (waves emitting from the rear side of the cone) that would otherwise be lost inside a sealed box. The sound waves bounce around inside the ported box until the exit through the port, reinforcing certain frequencies. As the signal material moves closer and closer to the enclosure's tuning frequency, cone motion decreases (for the same output) while enclosure efficiency rises. This creates an interesting phenomenon of the cone moving less and less, while output is going up. While sealed box systems rely 100% of sound waves radiated directly from the cone, the ported systems utilize those back waves to increase efficiency/output, but there in lies the sound quality differences between the two. Sealed boxes do not add this artificial efficiency based on frequency, it gives a smooth and consistant response along its entire useable frequency range. Ported box rely on the frequency of the material playing to determine its actual efficiency, therefore its efficiency is greater than a sealed box, but its reponse is also more erratic, less uniform.
Anyway, one last comment about ported boxes and cone motion. As I said, ported boxes generally allow less cone motion than do sealed boxes, ultimately based on frequency, but there is a time when cone motion becomes a real problem: below tuning. When your signal material dips below that which you tuned your enclosure to, this resistance on cone motion from the enclosure drops drastically. Basically once you deviate below tuning, cone motion starts increasing very rapidly until less an octave below tuning you run serious risk of bottoming out your speaker (resistance to cone motion becomes so little that the cone over-excurts). This is why people use sub-sonic filters... filters to block frequencies too low for the system to handle. Sealed systems do not have this problem, hence they tend to have the best low end extension.
Using PVC for ports can be acceptable, depending on the situation. Port noise is based on air velocity and the shape of the surface the air follows. The faster the air moves, the more likely for port noise (obviously, just as wind howls louder the faster it blows). Interestingly, the smaller the port diameter (called port area btw), the faster the air will have to move to pass through it given a certain pressure. So, the larger you make your port diameter, the less of a problem port noise is. Also, filleting the edges of the port can help noise as well, as its sharp edges that tend to be 'noisy'. Lastly, you can chose to use 'aeroports' if you want. They are ports designed with a certain shape to minimize port noise, they work pretty well.
Slot port versus round ports. Contrary to popular belief, round ports actually are the quietest type, given a certain port area. The square corners on slot ports are not low-resistance areas for moving air. The rounded edges of round ports make for a smoother passage for the air, where as the square corners of slot ports tend to turbulate the air, add resistance, etc. This nakes slot ports sound pretty lousy, but they have one big advantage: large amounts of port area. Slot ported boxes tend to have much more port area than their round ported counterparts, simply because its so much easier to get alot with a square port versus a round one. Many times a slot ported box has 2X to 3X the port area of a round ported counterpart. This means that while both the smaller round port and the larger slot port have the same tuning frequency (and all the performance similarities that go along with that), and while the slot port has the disadvantage of noisy square corners, having that much more port area means the air velocity inside the slot port will be much less than the round one, and ultimately offering less port noise than the round one.
The type of music you listening to determining the box type is only somewhat true. Ive heard some rock songs with pretty deep bass, and some rap songs with pretty shallow bass. Ive heard country songs bump and classical thunder. Do not place music types into one category or another. Instead look at the intended uses of the stereo in terms of accuracy, output, blending to the other components/speakers in the system, etc. Chosing a box type because you listen to rap, country, rock or whatever is not a good way to go about it. Looking at the efficiency and output levels you need/want, looking at the frequency response you need, looking at enclosure size, etc etc.... these are all better and more important things to consider when chosing the right enlcosure type.
Sorry, I do tend to drone on.
What Im getting at is while cone motion within a vented system is largely frequency based, generally speaking you get less cone motion from ported box systems than from sealed, let me explain...Sealed boxes resist cone motion in the obvious way, a 'cushion' of air provided by the sealed space. As the cone moves out from the box, a low pressure zone is created inside the box (volume inside box expands, amount of air molecules does not.... low pressure zone) and thus the higher air pressure outside the box/cone resists further cone motion. As the cone moves in, the opposite hhapens. The air in the box is compressed, creating a high pressure zone, thus putting force on the cone to move back out. This force always resists the cone's motion and tries to set it back to the home position. This creates the suspension cushion desired to give the right response desired from the subwoofer system.
Ported boxes work a bit differently. Obviously there is no sealed air cushion like the above type, the resistance comes from the port itself. As the cone moves in and out, its forcing air in and out through the port. The diameter and length of the port determine how much air can pass through it, and how much resistance it places on the cone's motion (which affects the enclosure's tuning frequency). Go jog around the block while breathing through a straw. The straw creates a resistance to your breathing due to being smaller than the needed space for the air to pass in and out freely (with no resistance). The diameter and length of the straw affect how much resistance it puts on the force pushing the air through it. The same thing goes for enclosure ports.
The advantage you get from ported boxes is the use of those backwaves (waves emitting from the rear side of the cone) that would otherwise be lost inside a sealed box. The sound waves bounce around inside the ported box until the exit through the port, reinforcing certain frequencies. As the signal material moves closer and closer to the enclosure's tuning frequency, cone motion decreases (for the same output) while enclosure efficiency rises. This creates an interesting phenomenon of the cone moving less and less, while output is going up. While sealed box systems rely 100% of sound waves radiated directly from the cone, the ported systems utilize those back waves to increase efficiency/output, but there in lies the sound quality differences between the two. Sealed boxes do not add this artificial efficiency based on frequency, it gives a smooth and consistant response along its entire useable frequency range. Ported box rely on the frequency of the material playing to determine its actual efficiency, therefore its efficiency is greater than a sealed box, but its reponse is also more erratic, less uniform.
Anyway, one last comment about ported boxes and cone motion. As I said, ported boxes generally allow less cone motion than do sealed boxes, ultimately based on frequency, but there is a time when cone motion becomes a real problem: below tuning. When your signal material dips below that which you tuned your enclosure to, this resistance on cone motion from the enclosure drops drastically. Basically once you deviate below tuning, cone motion starts increasing very rapidly until less an octave below tuning you run serious risk of bottoming out your speaker (resistance to cone motion becomes so little that the cone over-excurts). This is why people use sub-sonic filters... filters to block frequencies too low for the system to handle. Sealed systems do not have this problem, hence they tend to have the best low end extension.
Using PVC for ports can be acceptable, depending on the situation. Port noise is based on air velocity and the shape of the surface the air follows. The faster the air moves, the more likely for port noise (obviously, just as wind howls louder the faster it blows). Interestingly, the smaller the port diameter (called port area btw), the faster the air will have to move to pass through it given a certain pressure. So, the larger you make your port diameter, the less of a problem port noise is. Also, filleting the edges of the port can help noise as well, as its sharp edges that tend to be 'noisy'. Lastly, you can chose to use 'aeroports' if you want. They are ports designed with a certain shape to minimize port noise, they work pretty well.
Slot port versus round ports. Contrary to popular belief, round ports actually are the quietest type, given a certain port area. The square corners on slot ports are not low-resistance areas for moving air. The rounded edges of round ports make for a smoother passage for the air, where as the square corners of slot ports tend to turbulate the air, add resistance, etc. This nakes slot ports sound pretty lousy, but they have one big advantage: large amounts of port area. Slot ported boxes tend to have much more port area than their round ported counterparts, simply because its so much easier to get alot with a square port versus a round one. Many times a slot ported box has 2X to 3X the port area of a round ported counterpart. This means that while both the smaller round port and the larger slot port have the same tuning frequency (and all the performance similarities that go along with that), and while the slot port has the disadvantage of noisy square corners, having that much more port area means the air velocity inside the slot port will be much less than the round one, and ultimately offering less port noise than the round one.
The type of music you listening to determining the box type is only somewhat true. Ive heard some rock songs with pretty deep bass, and some rap songs with pretty shallow bass. Ive heard country songs bump and classical thunder. Do not place music types into one category or another. Instead look at the intended uses of the stereo in terms of accuracy, output, blending to the other components/speakers in the system, etc. Chosing a box type because you listen to rap, country, rock or whatever is not a good way to go about it. Looking at the efficiency and output levels you need/want, looking at the frequency response you need, looking at enclosure size, etc etc.... these are all better and more important things to consider when chosing the right enlcosure type.
Sorry, I do tend to drone on.
chvymudin3388
1/2 ton status
$329.95
High quality sub-woofer power.
Features include:
* Cast aluminum heat sink
* Detachable aluminum dress plate
* Top panel control
* Dual mono drive connection
* Class D amplifier circuit
* Variable bass boost with wired remote
* Built-in variable low-pass filter
* Built-in infrasonic filter
* Gold plated RCA inputs and outputs
* Speaker level input
* Power MOSFET switching power supply
* Single-side exposure of terminals for multi-installation
chevyin
1/2 ton status
$329 for a 500watt mono amp? Too much money, especially for Kenwood.
big4x4ride
1/2 ton status
hey im in corpus christi. pretty close to ya. if you eed some help with abox i can help ya out, built many mnay boxes, sealed ported, bandpass etc.
chvymudin3388
1/2 ton status
cool never thought id find some one close to me on the net lol what do you drive maybe ive seen it
blackblazer717
1/2 ton status
i have in my experience had the most luck with a ported box, but not a store bought one it needs to be hand built
LUKE
LUKE
gmtech954
Registered Member
back when i was working at a stereo shop we did a lot of sound quality comp cars and i will say for the cleanest sound go with a sealed enclosure. as for the amp that would def. not be one of my choices. For that price you could pick up a phoenix gold amp that would be a lot cleaner and more powerful. of course if you want sound quality and are willing to amp the whole system id look for an older xtant 3150 or 3300. Theyre a little more pricey but they are 83% efficient and are very clean.
84gmcjimmy
1 ton status
I don't mean to hijack, but I have a question. How do you tune a box when you build it to get in a certain frequency range? Any links or anything to help would be great.
chevyin, I bow to you, that is a lot of information
chevyin, I bow to you, that is a lot of information
tch777
1/2 ton status
Well about 11 years ago when the subs got popular in my small town college I decided I had to have some, but I was broke. Most everyone had those huge MTX boxes with 2, 12inchers in them. I thought they were pretty cool but I did not like how muddy they were. So long story short I bought a Pyramid 10 inch dual voice coil. I built a ported enclosure according to the pyramid reccomendations. I used 5/8 MDF, deck screws, PVC, silicone to seal the box joints, and a tar like speaker sealer around the speaker to box joint. I also stuffed the box with acoustic fill, get the dacron pillow stuffing at Wal-mart same stuff as the expensive stuff in the audio mags. I then wired the dual channels in parrallel and bridged the cheap California amp I had.
That sub hit hard and was clean. I didn't do any competition events with it , but I pissed off all the guys in my Fraternity and the others on Campus. I had about 250 into all of it and only the guys that dropped over around 750 with custom systems and boxes sounded better.
In my opinion 10 inch subs are the best all around sub. They just cover the spectrum of sub and bass really good for all types of music. The 12s and bigger are better for hitting deeper lows but they always sound muddy to me and slow for Rock and Metal. Plus they take less power to run and smaller enclosures. Also when you get it all going, find all the rattles that the sub(s) make and get rid of them. To me there is nothing worse than a great system that eveyone can hear rattling the body of the vehicle. Loose Liscense plates and deck lids are the worst. I had to use all 4 screws on my liscense plates with blue loctite so it wouldn't rattle.
Good luck
That sub hit hard and was clean. I didn't do any competition events with it , but I pissed off all the guys in my Fraternity and the others on Campus. I had about 250 into all of it and only the guys that dropped over around 750 with custom systems and boxes sounded better.
In my opinion 10 inch subs are the best all around sub. They just cover the spectrum of sub and bass really good for all types of music. The 12s and bigger are better for hitting deeper lows but they always sound muddy to me and slow for Rock and Metal. Plus they take less power to run and smaller enclosures. Also when you get it all going, find all the rattles that the sub(s) make and get rid of them. To me there is nothing worse than a great system that eveyone can hear rattling the body of the vehicle. Loose Liscense plates and deck lids are the worst. I had to use all 4 screws on my liscense plates with blue loctite so it wouldn't rattle.
Good luck
chevyin
1/2 ton status
I apologize in advance for the length of this post. 
-------------------------------------------------------------------------------
Enclosure volume: Vb = 15 Vas (Qts^2.87)
Theoretical cut-off frequency: F3 = 0.26 Fs (Qts^ -1.4)
Tuning frequency: Fb = 0.42 Fs (Qts^ -0.9)
If an ideal box is to large for your application, choose an enclosure size in cu.ft. then
Find: F3 = (Vas / Vb)^1/2 (Fs)(an exponent to 1/2 is the same as taking the square root)
New tuning frequency: Fb = (Vas / Vb)^0.32 (Fs)
Note: these formulas for the "ideal" enclosure provide a flat response curve, reasonably low F3, and fair transient response. The smaller you make the enclosure, the larger the peak in the response curve, the higher the F3, and the poorer the transient response. Enclosures much smaller than the "ideal" alignment will sound muddled and boomy.
-------------------------------------------------------------------------------
To understand those equations, you have to understand what a speaker's theil/small perameters are.
Basically theil/small perameters are specs measured for each speaker (using standardized test formats) that can be used to predict how a speaker will react in a specific enclosure (usually using computer based modeling programs). Here's a well accepted definition of the theil/small perameters:
-------------------------------------------------------------------------------
"Thiele-Small Parameters
In the early seventies, several technical papers were presented to the AES (Audio Engineering Society) that resulted in the development of what we know today as 'Thiele-Small Parameters'. These papers were authored by A.N.Thiele and Richard H. Small. Thiele was the senior engineer of design and development for the Australian Broadcasting Commission and was responsible at the time for the Federal Engineering Laboratory, as well as for analyzing the design of equipment and systems for sound and vision broadcasting. Small was, at the time, a Commonwealth Post-graduate Research Student in the School of Electrical Engineering at the University of Sydney.
Thiele and Small devoted considerable effort to show how the following parameters define the relationship between a speaker and a particular enclosure. However, they can be invaluable in making choices because they tell you far more about the transducer's real performance than the basic benchmarks of size, maximum power rating or average sensitivity.
Fs------This parameter is the free-air resonant frequency of a speaker. Simply stated, it is the point at which the weight of the moving parts of the speaker becomes balanced with the force of the speaker suspension when in motion. If you've ever seen a piece of string start humming uncontrollably in the wind, you have seen the effect of reaching a resonant frequency. It is important to know this information so that you can prevent your enclosure from 'ringing'. With a loudspeaker, the mass of the moving parts, and the stiffness of the suspension (surround and spider) are the key elements that affect the resonant frequency. As a general rule of thumb, a lower Fs indicates a woofer that would be better for low-frequency reproduction than a woofer with a higher Fs. This is not always the case though, because other parameters affect the ultimate performance as well.
Re--------This is the DC resistance of the driver measured with an ohm meter and it is often referred to as the 'DCR'. This measurement will almost always be less than the driver's nominal impedance. Consumers sometimes get concerned the Re is less than the published impedance and fear that amplifiers will be overloaded. Due to the fact that the inductance of a speaker rises with a rise in frequency, it is unlikely that the amplifier will often see the DC resistance as its load.
Le--------This is the voice coil inductance measured in millihenries (mH). The industry standard is to measure inductance at 1,000 Hz. As frequencies get higher there will be a rise in impedance above Re. This is because the voice coil is acting as an inductor. Consequently, the impedance of a speaker is not a fixed resistance, but can be represented as a curve that changes as the input frequency changes. Maximum impedance (Zmax) occurs at Fs.
Q Parameters---------Qms, Qes, and Qts are measurements related to the control of a transducer's suspension when it reaches the resonant frequency (Fs). The suspension must prevent any lateral motion that might allow the voice coil and pole to touch (this would destroy the loudspeaker). The suspension must also act like a shock absorber. Qms is a measurement of the control coming from the speaker's mechanical suspension system (the surround and spider). View these components like springs. Qes is a measurement of the control coming from the speaker's electrical suspension system (the voice coil and magnet). Opposing forces from the mechanical and electrical suspensions act to absorb shock. Qts is called the 'Total Q' of the driver and is derived from an equation where Qes is multiplied by Qms and the result is divided by the sum of the same.
As a general guideline, Qts of 0.4 or below indicates a transducer well suited to a vented enclosure. Qts between 0.4 and 0.7 indicates suitability for a sealed enclosure. Qts of 0.7 or above indicates suitability for free-air or infinite baffle applications. However, there are exceptions! The Eminence Kilomax 18 has a Qts of 0.56. This suggests a sealed enclosure, but in reality it works extremely well in a ported enclosure. Please consider all the parameters when selecting loudspeakers. If you are in any doubt, contact your Eminence representative for technical assistance
Vas/Cms--------Vas represents the volume of air that when compressed to one cubic meter exerts the same force as the compliance (Cms) of the suspension in a particular speaker. Vas is one of the trickiest parameters to measure because air pressure changes relative to humidity and temperature — a precisely controlled lab environment is essential. Cms is measured in meters per Newton. Cms is the force exerted by the mechanical suspension of the speaker. It is simply a measurement of its stiffness. Considering stiffness (Cms), in conjunction with the Q parameters gives rise to the kind of subjective decisions made by car manufacturers when tuning cars between comfort to carry the president and precision to go racing. Think of the peaks and valleys of audio signals like a road surface then consider that the ideal speaker suspension is like car suspension that can traverse the rockiest terrain with race-car precision and sensitivity at the speed of a fighter plane. It’s quite a challenge because focusing on any one discipline tends to have a detrimental effect on the others
Vd------This parameter is the Peak Diaphragm Displacement Volume — in other words the volume of air the cone will move. It is calculated by doubling Xmax (Voice Coil Overhang of the driver) then multiplying the result by Sd (Surface area of the cone). Vd is noted in cc. The highest Vd figure is desirable for a sub-bass transducer
BL------Expressed in Tesla meters, this is a measurement of the motor strength of a speaker. Think of this as how good a weightlifter the transducer is. A measured mass is applied to the cone forcing it back while the current required for the motor to force the mass back is measured. The formula is mass in grams divided by the current in amperes. A high BL figure indicates a very strong transducer that moves the cone with authority!
Mms------This parameter is the combination of the weight of the cone assembly plus the ‘driver radiation mass load’. The weight of the cone assembly is easy: it’s just the sum of the weight of the cone assembly components. The driver radiation mass load is the confusing part. In simple terminology, it is the weight of the air (the amount calculated in Vd) that the cone will have to push
Rms------This parameter represents the mechanical resistance of a driver’s suspension losses. It is a measurement of the absorption qualities of the speaker suspension and is stated in N*sec/m.
EBP-----This measurement is calculated by dividing Fs by Qes. The EBP figure is used in many enclosure design formulas to determine if a speaker is more suitable for a closed or vented design. An EBP close to 100 usually indicates a speaker that is best suited for a vented enclosure. On the contrary, an EBP closer to 50 usually indicates a speaker best suited for a closed box design. This is merely a starting point. Many well-designed systems have violated this rule of thumb! Qts should also be considered.
Xmax/Xmech--------Short for Maximum Linear Excursion. Speaker output becomes non-linear when the voice coil begins to leave the magnetic gap. Although suspensions can create non-linearity in output, the point at which the number of turns in the gap (see BL) begins to decrease is when distortion starts to increase. Eminence has historically been very conservative with this measurement and indicated only the voice coil overhang (Xmax: Voice coil height minus top plate thickness, divided by 2). Xmech is expressed by Eminence as the lowest of four potential failure condition measurements times 2: Spider crashing on top plate; Voice coil bottoming on back plate; Voice coil coming out of gap above core; Physical limitation of cone. Take the lowest of these measurements then multiply it by two. This gives a distance that describes the maximum mechanical movement of the cone.
Sd------This is the actual surface area of the cone, normally given in square cm.
Zmax-----This parameter represents the speaker’s impedance at resonance." -http://caraudiotalk.com/forum/index.php?act=tutorials&CODE=view&id=4
-------------------------------------------------------------------------------
So that's how ported boxes are specifically tuned. When designing the box, you tune it to a specific frequency (through equations/programs using T/S specs), for example 30hz. This means when you play a 30hz note, the box is at its most efficient, the cone will move the least, but over all output will be the greatest. As the frequency raises higher above tuning, enclosure efficiency decreases and the speaker does more of the work due to cone motion increasing (slowly). Generally a vented enclosure will give a peak boost of 3-4 decibels, at tuning, and will gradually slope off to a flatter response in the higher freqs. The tuning frequency of the enclosure determines the lowest playable frequency of the subwoofer system. Generally the upper most frequency the subwoofer system will play is determined by how the use sets the crossover (to cut out high freqs subs dont play).
Sealed enclosures are tuned by way of internal volume also. But unlike ported systems, sealed boxes are not tuned to specific frequencies, they are tuned to create specific response curves. The size of the sealed box determines how much of an air cushion it provides to the moving cone. This affects the speaker's frequency response. This phenomenon is called the sealed system's Qtc. I'll quote yet again to explain further:
-------------------------------------------------------------------------------
"Qtc - value for the damping provided for a driver in a sealed enclosure. Denotes the enclosures ability to control the driver response at resonance. Qtc = 0.707 is the optimum value for sealed enclosures, providing flattest response and highest SPL for deep bass extension. Enclosures for this value are often rather large. Lower Qtc can give even better transient response, down to a Qtc of 0.577 for the best damping and transients, but the enclosure is usually huge and SPL's are down. A Qtc of 1.0 is a compromise between deep bass and transient response vs. smaller sized enclosure. Larger subs can go with an even higher Qtc, as their resonant frequency is often very low, but Qtc's above 1.5 can begin to sound very muddled and boomy, and sacrifice deep bass extension and transient response for enhanced mid-bass peaks (louder)."
-------------------------------------------------------------------------------
Woofer 'speed' is not based on motor force versus the cone and coil's moving mass (BL vs Mms) as common sense would seem to imply, but is only a factor of the amount of current passing through the speaker. If this topic interests you more, you can read more about it on Adire's tech paper found here: http://www.adireaudio.com/Files/TechPapers/WooferSpeed.pdf
Generally when someone says they are tuning a box, they are referring to a vented (ported) enclosure. Ported enclosure tuning is dictated by three things: 1) enclosure internal volume, 2) port area (cross-sectional length x width for rectanglar ports, Pi x r^2 for round ports), and 3) length of the ports. In other words, go back to my example of running around the block while breathing through a straw... how easily this is accomplished would depend on how big the straw is (diameter), and how long it is. If its excessively small (diameter) or excessively long, it will be more difficult. Enclosure ports work the same way, the area of the port (diameter of the straw in my example) and port length effect how much air is allow in and out of the port, and how much restriction it places on the air's movement. To understand how internal volume affects tuning, Im going to quote a couple things that explain better than my own words would:84gmcjimmy said:I don't mean to hijack, but I have a question. How do you tune a box when you build it to get in a certain frequency range? Any links or anything to help would be great.
chevyin, I bow to you, that is a lot of information
-------------------------------------------------------------------------------
Optimum volume for ported enclosure (cubic ft):
These formulas were engineered by D.B. Keele Jr. using the vented enclosure alignments developed by A.N. Thiele. Enclosure volume: Vb = 15 Vas (Qts^2.87)
Theoretical cut-off frequency: F3 = 0.26 Fs (Qts^ -1.4)
Tuning frequency: Fb = 0.42 Fs (Qts^ -0.9)
If an ideal box is to large for your application, choose an enclosure size in cu.ft. then
Find: F3 = (Vas / Vb)^1/2 (Fs)(an exponent to 1/2 is the same as taking the square root)
New tuning frequency: Fb = (Vas / Vb)^0.32 (Fs)
Note: these formulas for the "ideal" enclosure provide a flat response curve, reasonably low F3, and fair transient response. The smaller you make the enclosure, the larger the peak in the response curve, the higher the F3, and the poorer the transient response. Enclosures much smaller than the "ideal" alignment will sound muddled and boomy.
-------------------------------------------------------------------------------
To understand those equations, you have to understand what a speaker's theil/small perameters are.
Basically theil/small perameters are specs measured for each speaker (using standardized test formats) that can be used to predict how a speaker will react in a specific enclosure (usually using computer based modeling programs). Here's a well accepted definition of the theil/small perameters:
-------------------------------------------------------------------------------
"Thiele-Small Parameters
In the early seventies, several technical papers were presented to the AES (Audio Engineering Society) that resulted in the development of what we know today as 'Thiele-Small Parameters'. These papers were authored by A.N.Thiele and Richard H. Small. Thiele was the senior engineer of design and development for the Australian Broadcasting Commission and was responsible at the time for the Federal Engineering Laboratory, as well as for analyzing the design of equipment and systems for sound and vision broadcasting. Small was, at the time, a Commonwealth Post-graduate Research Student in the School of Electrical Engineering at the University of Sydney.
Thiele and Small devoted considerable effort to show how the following parameters define the relationship between a speaker and a particular enclosure. However, they can be invaluable in making choices because they tell you far more about the transducer's real performance than the basic benchmarks of size, maximum power rating or average sensitivity.
Fs------This parameter is the free-air resonant frequency of a speaker. Simply stated, it is the point at which the weight of the moving parts of the speaker becomes balanced with the force of the speaker suspension when in motion. If you've ever seen a piece of string start humming uncontrollably in the wind, you have seen the effect of reaching a resonant frequency. It is important to know this information so that you can prevent your enclosure from 'ringing'. With a loudspeaker, the mass of the moving parts, and the stiffness of the suspension (surround and spider) are the key elements that affect the resonant frequency. As a general rule of thumb, a lower Fs indicates a woofer that would be better for low-frequency reproduction than a woofer with a higher Fs. This is not always the case though, because other parameters affect the ultimate performance as well.
Re--------This is the DC resistance of the driver measured with an ohm meter and it is often referred to as the 'DCR'. This measurement will almost always be less than the driver's nominal impedance. Consumers sometimes get concerned the Re is less than the published impedance and fear that amplifiers will be overloaded. Due to the fact that the inductance of a speaker rises with a rise in frequency, it is unlikely that the amplifier will often see the DC resistance as its load.
Le--------This is the voice coil inductance measured in millihenries (mH). The industry standard is to measure inductance at 1,000 Hz. As frequencies get higher there will be a rise in impedance above Re. This is because the voice coil is acting as an inductor. Consequently, the impedance of a speaker is not a fixed resistance, but can be represented as a curve that changes as the input frequency changes. Maximum impedance (Zmax) occurs at Fs.
Q Parameters---------Qms, Qes, and Qts are measurements related to the control of a transducer's suspension when it reaches the resonant frequency (Fs). The suspension must prevent any lateral motion that might allow the voice coil and pole to touch (this would destroy the loudspeaker). The suspension must also act like a shock absorber. Qms is a measurement of the control coming from the speaker's mechanical suspension system (the surround and spider). View these components like springs. Qes is a measurement of the control coming from the speaker's electrical suspension system (the voice coil and magnet). Opposing forces from the mechanical and electrical suspensions act to absorb shock. Qts is called the 'Total Q' of the driver and is derived from an equation where Qes is multiplied by Qms and the result is divided by the sum of the same.
As a general guideline, Qts of 0.4 or below indicates a transducer well suited to a vented enclosure. Qts between 0.4 and 0.7 indicates suitability for a sealed enclosure. Qts of 0.7 or above indicates suitability for free-air or infinite baffle applications. However, there are exceptions! The Eminence Kilomax 18 has a Qts of 0.56. This suggests a sealed enclosure, but in reality it works extremely well in a ported enclosure. Please consider all the parameters when selecting loudspeakers. If you are in any doubt, contact your Eminence representative for technical assistance
Vas/Cms--------Vas represents the volume of air that when compressed to one cubic meter exerts the same force as the compliance (Cms) of the suspension in a particular speaker. Vas is one of the trickiest parameters to measure because air pressure changes relative to humidity and temperature — a precisely controlled lab environment is essential. Cms is measured in meters per Newton. Cms is the force exerted by the mechanical suspension of the speaker. It is simply a measurement of its stiffness. Considering stiffness (Cms), in conjunction with the Q parameters gives rise to the kind of subjective decisions made by car manufacturers when tuning cars between comfort to carry the president and precision to go racing. Think of the peaks and valleys of audio signals like a road surface then consider that the ideal speaker suspension is like car suspension that can traverse the rockiest terrain with race-car precision and sensitivity at the speed of a fighter plane. It’s quite a challenge because focusing on any one discipline tends to have a detrimental effect on the others
Vd------This parameter is the Peak Diaphragm Displacement Volume — in other words the volume of air the cone will move. It is calculated by doubling Xmax (Voice Coil Overhang of the driver) then multiplying the result by Sd (Surface area of the cone). Vd is noted in cc. The highest Vd figure is desirable for a sub-bass transducer
BL------Expressed in Tesla meters, this is a measurement of the motor strength of a speaker. Think of this as how good a weightlifter the transducer is. A measured mass is applied to the cone forcing it back while the current required for the motor to force the mass back is measured. The formula is mass in grams divided by the current in amperes. A high BL figure indicates a very strong transducer that moves the cone with authority!
Mms------This parameter is the combination of the weight of the cone assembly plus the ‘driver radiation mass load’. The weight of the cone assembly is easy: it’s just the sum of the weight of the cone assembly components. The driver radiation mass load is the confusing part. In simple terminology, it is the weight of the air (the amount calculated in Vd) that the cone will have to push
Rms------This parameter represents the mechanical resistance of a driver’s suspension losses. It is a measurement of the absorption qualities of the speaker suspension and is stated in N*sec/m.
EBP-----This measurement is calculated by dividing Fs by Qes. The EBP figure is used in many enclosure design formulas to determine if a speaker is more suitable for a closed or vented design. An EBP close to 100 usually indicates a speaker that is best suited for a vented enclosure. On the contrary, an EBP closer to 50 usually indicates a speaker best suited for a closed box design. This is merely a starting point. Many well-designed systems have violated this rule of thumb! Qts should also be considered.
Xmax/Xmech--------Short for Maximum Linear Excursion. Speaker output becomes non-linear when the voice coil begins to leave the magnetic gap. Although suspensions can create non-linearity in output, the point at which the number of turns in the gap (see BL) begins to decrease is when distortion starts to increase. Eminence has historically been very conservative with this measurement and indicated only the voice coil overhang (Xmax: Voice coil height minus top plate thickness, divided by 2). Xmech is expressed by Eminence as the lowest of four potential failure condition measurements times 2: Spider crashing on top plate; Voice coil bottoming on back plate; Voice coil coming out of gap above core; Physical limitation of cone. Take the lowest of these measurements then multiply it by two. This gives a distance that describes the maximum mechanical movement of the cone.
Sd------This is the actual surface area of the cone, normally given in square cm.
Zmax-----This parameter represents the speaker’s impedance at resonance." -http://caraudiotalk.com/forum/index.php?act=tutorials&CODE=view&id=4
-------------------------------------------------------------------------------
So that's how ported boxes are specifically tuned. When designing the box, you tune it to a specific frequency (through equations/programs using T/S specs), for example 30hz. This means when you play a 30hz note, the box is at its most efficient, the cone will move the least, but over all output will be the greatest. As the frequency raises higher above tuning, enclosure efficiency decreases and the speaker does more of the work due to cone motion increasing (slowly). Generally a vented enclosure will give a peak boost of 3-4 decibels, at tuning, and will gradually slope off to a flatter response in the higher freqs. The tuning frequency of the enclosure determines the lowest playable frequency of the subwoofer system. Generally the upper most frequency the subwoofer system will play is determined by how the use sets the crossover (to cut out high freqs subs dont play).
Sealed enclosures are tuned by way of internal volume also. But unlike ported systems, sealed boxes are not tuned to specific frequencies, they are tuned to create specific response curves. The size of the sealed box determines how much of an air cushion it provides to the moving cone. This affects the speaker's frequency response. This phenomenon is called the sealed system's Qtc. I'll quote yet again to explain further:
-------------------------------------------------------------------------------
"Qtc - value for the damping provided for a driver in a sealed enclosure. Denotes the enclosures ability to control the driver response at resonance. Qtc = 0.707 is the optimum value for sealed enclosures, providing flattest response and highest SPL for deep bass extension. Enclosures for this value are often rather large. Lower Qtc can give even better transient response, down to a Qtc of 0.577 for the best damping and transients, but the enclosure is usually huge and SPL's are down. A Qtc of 1.0 is a compromise between deep bass and transient response vs. smaller sized enclosure. Larger subs can go with an even higher Qtc, as their resonant frequency is often very low, but Qtc's above 1.5 can begin to sound very muddled and boomy, and sacrifice deep bass extension and transient response for enhanced mid-bass peaks (louder)."
-------------------------------------------------------------------------------
It is a common misconception that speaker cone size affects such things as how 'fast' it is or what types of music it works best with. These ideas are simply untrue. Cone size does however affect its frequency response curve. The lower the frequency of a note, the more air that needs to be displaced in order to reproduce that note at any given volume level. So, a larger coned sub (18 versus 10 for example) will most defintely reproduce a 20hz note with more authority than will its 10" counterpart. At some point cone size does affect upper end frequency extension, but car audio subwoofers should never play above 80-120hz anyway (50-60hz ideally). Basically, you want to chose a subwoofer size that accomodates your needs. Larger subs get louder, but also require a larger box. You wont be fitting an 18" sub in a 2-seater compact, but you could fit a 10", for example. Also, you want to size your sub based on the rest of the system. If your front stage consists of 4x6's in the dash, chances are they wont be able to keep up with the output of a decent 18, nor will they reproduce the midbass needed to compliment the monster low ends the 18 will put out. You'll end up with a bass-heavy system. Likewise, if you already have 8" dedicated midbass drivers in your doors playing down to 60hz, it doesn't make alot of sense to only go with 10" subwoofers (for obvious output and frequency response issues).tch777 said:
Woofer 'speed' is not based on motor force versus the cone and coil's moving mass (BL vs Mms) as common sense would seem to imply, but is only a factor of the amount of current passing through the speaker. If this topic interests you more, you can read more about it on Adire's tech paper found here: http://www.adireaudio.com/Files/TechPapers/WooferSpeed.pdf
tch777
1/2 ton status
That is an important point consider your overall system. I am not an expert and I have not messed around with this stuff for 6 years either. It just seemed to me that the 12s and bigger were muddy and slow. But that could also be attributed to improper system balance in set up. Also I imagine if they didn't have enough amp to run them or possilbly Caps may have been needed too. But the point that I think Chevyin makes that is really important is balancing all the components. Beyond the rattles thing a system that is all bass and tinny tweaters is pretty cheesy too.
89GMCSuburban
1/2 ton status
My suggestion is to not touch a kenwood amp. My fosgate smokes my friend's Kenwood, and his Kenwood is rated 200 watts higher than mine. Compare the size between a Fosgate and a Kenwood of the same wattage. You'll notice the Fosgate is larger...more room for capacitors, etc.
If you listen to rock/metal, get yourself 2 12" subs, a GOOD amp, and a Q-logic sealed enclosure (not a bandpass) with NO PORTS. Ports promote extra movement, so if you are looking for a quick thump, like in a bass drum in metal/country/pop, you want it to be sealed for a quick sound.
EDIT: Here's my recommendations
Two of these : http://www.millionbuy.com/rocp212s4.html
One of these : http://www.millionbuy.com/rocp6002.html
And one of these : http://www.millionbuy.com/hbx12sqb.html
I bought my stuff from these guys, never had any problems with the company. Browse the site, too....good stuff.
If you listen to rock/metal, get yourself 2 12" subs, a GOOD amp, and a Q-logic sealed enclosure (not a bandpass) with NO PORTS. Ports promote extra movement, so if you are looking for a quick thump, like in a bass drum in metal/country/pop, you want it to be sealed for a quick sound.
EDIT: Here's my recommendations
Two of these : http://www.millionbuy.com/rocp212s4.html
One of these : http://www.millionbuy.com/rocp6002.html
And one of these : http://www.millionbuy.com/hbx12sqb.html
I bought my stuff from these guys, never had any problems with the company. Browse the site, too....good stuff.
gmtech954
Registered Member
remember you cant always go by advertised wattage. some (cheaper)amps rate their amps at wattage that theres no way it will ever produce without severe distortion (example pyramid 1500 watt amp) but also some high end amps that are designed for comp underate. I had a couple of the old phoenix gold zx series amps. the zx 350 i had was rated at 18x2 but had no problem killing jl w4d4 subs rated at 500watts.
