i have 2 15" sub woofers with dual 1 ohm voice coils. they are rated at 1000W RMS/2000 peak. The manufacture recommends "Pe (Watts-RMS) 200-500 Watts. that is in a 5.0 cubic feet enclosure. the way i understand it is that i need a total of 10 cubic feet internal (5 for each sub). I should have paid attention in algebra How can i find the dimensions of this box and I would like to run 2 class D amps (1 to each sub) and need some help on what a good setup would be.
Thanks
Replies (27)
Victor on 09/26/2006 17:50:25
what sub is this???
Colt45 on 09/26/2006 18:00:36
It is a Powerbass 3XL-15D Something new i am trying out
Victor on 09/26/2006 18:06:30
do u ahve yahoo, msn or skype realtime messengers?? if yes.. my id on yahoo is victorginger
msn is victorexports@hotmail.com
skype is victorginger
its much better to take this online.
Colt45 on 09/26/2006 20:58:40
any other opinions on this?
Victor has been helping me but i would like others opinions also
swez on 09/27/2006 08:46:22
Looks like a pretty strong woofer here Colt: This one?
http://www.audio-warehouse.com/web/mdl/3XL-15D/detail.asp
Do you have a mfg's link to enclosure and specs on them? A few guys have mentioned Powerbass subs here in the past few months and from the general specs noted, this sub can take some serious power and very efficient too. These are specs we see in Pro line Sound Reinforcement woofers.
3" voice coil
1+1 DVC
1000 Watt (RMS)
Sensitivity: 93dB SPL @ 1w/1m
General thoughts: Since this sub likes huge ported boxes and are very efficient already, I would seriously consider a single sub/amp pairing here. I see a potential of 150 dB + bass engine here already with just 1 sub and amp. A box of this size and porting needs will probably weigh close to 300 lbs alone. (1" MDF box panels, 1.5" speaker mounting panel and 5/8" thick port material)
Trunk space avaialble in this car is what? I have some concerns about getting this size enclosure into the trunk. One has to consider the "mouth opening" dimensions of the trunk here too. What good is it to build a great box and not be able to fit it into the car??? Want to avoid that scenario right?
Height: 18" min?
Width: Max wide to work with... don't forget the wheel wells cut space
Depth: Max depth available
Port tuning freq: Got a target here yet?
Box area calculations:
H x W x D/1728 = # of cubic feet externally, the box will take up physically.
For internal cf numbers, we have to consider the wood thickness used for the box, woofer & port displacements as well.
Comments?
Swez
Colt45 on 09/28/2006 15:20:31
I have been mulling over the box size:trunk size problem for the past few days. I really would like to get both subs into the car.
Is it possible to build the box inside of the car?
Yes I do have the TH Parameters for these subs in a pdf format and can email them to you if you like.
I dont understand about the ports i guess. 5/8" material not sure what you mean by this.
Have seen 2 of these subs installed in a 1996 toyota celica before. Not sure what type of box they had though. May have been a sealed box but the manufature gives a warning not to put them in sealed boxes. I am not sure why i am sure that you could probably tell me.
I have no idea about port tuning frequency ??
Have built a few boxes before but never to any specs like i am wanting to do now. Just built them to fit in the space that was needed and to accomodate the speakers.
Ummm
about 36" wide
i am thinking of laying the back seats down to be able to get more depth?? About 36" with the seats up
and height about 16 - 17"
swez on 09/28/2006 19:23:54
If using a sloted port/vent here, the port/vent wood thickness can be 5/8" thick to cut down on weight and space these segments take up in the box. The other option is just using 4" round ports to the proper length. These can be of PVC drain pipe and easily cut and glued to fit.
Building a box inside a small sedan... I wouldn't even entertain that thought. Maybe Paul Tuttle Jr. would... but Paul Sr. would have a stroke over that one.
Lets see... about how large a 5 cf box would be based on your given dimensions:
Max Height: 17"
Max Width: 36"
Max Depth" 20"
Board thickness: 1.0"
This nets an internal airspace of 5.3 cf. Then we have to subtract the woofer and port displacements to get as close as possible to your target 5.0 cf internal.
Now, for a pair of these subs, we'll just change a few basic parameters and see what that looks like. This would be 2 boxes, side by side,
Hmax: 17"
Wmax: 35"
Dmax: 39"
This nets a box with 10.6 cf internal and by the time we subtract subs, ports and divider board displacements, you'll be pretty darn close to a nut busting 10.0 cf.
Can you imagine getting a box of that size, into the mouth of this trunk? Make a card board proof of this domension and see.
Swez
Colt45 on 09/28/2006 19:35:12
well Swez my man I am sure gonna try it
the subs take up approx 1/4 cu ft (just found that out)
so i should build a box with 2 seperate compartments?
will there need to be a port in each compartment, i assume so
making it out of cardboard is a good idea never thought of that and i am going to try it if i can find enough cardboard. lol
i love doing this stuff :)
Colt45 on 09/28/2006 19:47:33
oh can i build the 2 seperate boxes, get them in the car and then put them together?
oh and this is the specs they give on optimum ported volume
Gross Vb internal 5.0 cu ft have been told by Victor i should be about 5.4 cu ft
Circular Port 6" x 7.5" D
Fb (Box Tuning) 40Hz
F3 (-3dB Cutoff) 33Hz
Pe (Watts-RMS) 250-500 Watts
Subsonic Filter Setting if applicable 35 Hz What exactly is this?
swez on 09/28/2006 22:03:49
Yeah.... cardboard cut-outs mang. Just like in model making classes. It gives a good idea of the over all foot print and how much space they will take up.
Yes, I would definitely consider building this system in matched, dual boxes. This makes them easier to handle, install and building them is just a tad more work.
Circular Port 6" x 7.5" D (Porting dimensions)
Fb (Box Tuning) 40 Hz. = (Port tuning frequency target, based on internal box volume, minus sub and port displacements)
F3 (-3dB Cutoff) 33Hz. = (Lowest frequency subs will reach with usable SPL levels
Pe (Watts-RMS) 250-500 Watts = (Average power levels sub can work with)
Subsonic Filter Setting if applicable 35 Hz. What exactly is this?
(SSF or infrasonic filters are used to protect the woofers from damage at frequencies below Port tuning) When using high powered ported/vented enclosures, we must use these filters to keep the sub cones from "unloading", (going out of control) below tuning point.
These are all speaker/sub specifications a design engineer uses to calculate the performance characteristics of a given speaker/sub in various enclosure types.
FYI: With a Vb of 5.0 cf, a 6" dia, port of 7.5" nets a tuning frequency of 36 Hz. Not a bad place to be at all.
swez
Colt45 on 09/29/2006 11:36:45
if you were to just guess what kind of spl numbers do you think you could get from this setup?
and what do you think the difference would be from having a single sub or 2 subs
that is if these boxes are to specs just like the numbers show
swez on 09/29/2006 12:54:29
Your SPL numbers with one well designed box, 1 strong sub and 1000 watts RMS should put you pretty close to 150dB. Sound dampening doors and other panels will bring that number up as well.
If you went with 2 of everything, the SPL number would be about 3-5 more dB of SPL. Is that really worth all the extra cash, efforts and electrical upgrades that would go with it??? Only you can say.
Basically, this is one very efficient sub. (93dB @ 1 watt/1meter... assuming this is accurate) Most subs range from 85-88dB SPL @ 1w/1m. With ported enclosures, we can pick up 4-6dB SPL more, at the Port Tuning Frequency point and points 1/4 octave above PTF.
Also, if we double the amping power and add a 2nd sub, we get about +3 dB more bass in sealed enclosures. In ported sub enclosures, we might see +4 to +6 dB more SPL.
Now comes the real kicker... "Cabin gain affect"! In a larger vehicle, bass couples with the cabin and we can get a whopping +10 to +15dB more SPL at cabin resonance frequency. This is free and all we need do is enjoy and design for that added bump.
In smaller vehicles and single cab trucks, the cabin gain often much less. So, to hit high SPL #'s here, we have to seal the cabin as tightly as possible and use expensive power amps and subs to get the same net output levels.
Think this one through Colt... I really think you can get very good results with just one amp, 1 sub and a well designed ported enclosure. If this were not so, I would not put that in writing bud!
FYI: After serving this forum for 8 years now and doing Pro Sound projects for over 10 years now, there's a lot more to know than anyone can write in a few paragraphs.
Victor and I are giving you just the basics at this point. It's done that way for a very good reason too. What good would it be to hand you a 50 page tuitorial, written at engineering grade levels and have you get stuck on page 2? Suffice to say, we could easily do the A-Z, What... How and Why dog and pony show... but if the reader cannot understand it all, what's the point?
So, for now... we are giving you a small slice of the WHAT and HOW aspects to consider. The WHY is important, (to be sure) but it makes little sense to load ya down with technical theory, complex math equations and the like.
If one has an engineering background, then a debate would ensue. But at least then, we'd all be talking roughly the same language and the debate would be an exchange of cogent ideas and applied science.
Nuff said... COFFEE
swez
PS Where to next Kimosabe?
Colt45 on 09/29/2006 13:22:40
Ok now you about have me convinced to use just one 15" sub but before i make that decision i have a question for you.
Here are the specs for the same line of sub but 12"
Gross Vb Internal 2.0 cu ft
Circular Port 5" x 14.75 " D
Fb (Box Tuning) 38 Hz
F3 (-3db Cutoff) 32 Hz
Pe (Watts-RMS) 250-850 Watts
Subsonic Filter Setting 35 Hz
That is for each sub.
Would 2 of these subs produce about the same SPL as one 15" sub?
Would it be better to go with these?
swez on 09/29/2006 16:15:38
That's a fair question and trig/calc were not my strong suits in school...
If it happens to be yours, measuring the total "surface area" of each cone size from the surrounds' edge to the voice coil would give you one part of the equation. The other parts are to know the X-max of the 12 and 15 subs and also factor in effeciency numbers.
I have heard a few guys say... "The cone size of a typical 15" sub is about equal to a pair of 12" subs of the same family". Is that 100%, 50% or not even close to accurate? I dunno?
However, what we do know is that if we double the cone radiation area from "X" to "X sq'd" we pick up +3dB, as long as the power input is the same and so is the efficiency.
If we looked at the eff rating of the 15 VS the 12's and that # is +3dB or higher, cone area is often the key reason. Here, we excite a larger cone with the same electrical power applied and because the cone area is larger in the 15" cone, we move more air and a larger pressure wave. Hense, more SPL. (A measure of pressure levels from a given transducer... SPL = Sound Pressure Level)
Not sure if that answers the question or raises more questions, but those are the basic principles at work in speakers and woofers.
Care to take a stab at the math? We want to compare the radiating area of a 12" vs a 15" sub cone. Admittedly, I slept through the advanced math classes like Trig & Calc. D'oh... where's my dunce cap? ;-(
Swez
swez on 09/30/2006 10:46:48
OK, sounds like you and Victor had a YIM chat last night... what was the general concenses of your chat?
swez
Colt45 on 12/5/2006 16:53:37
Well I am back from a break away from the cones and amps, wires and voltage and have found some interesting news.
Las Vegas, NV (Nov 2, 2006)—Competing in a field that included nearly 2,000 new products from numerous different companies, PowerBass was the proud recipient of two International New Product Awards at the 2006 SEMA Show. The PowerBass 3XL-12D subwoofer was selected for top honors by the editors of Automaxx magazine of the Netherlands and Car Stereo Tuning of Brazil. Only a handful of other car audio products received recognition at the awards ceremony held November 1st at the Las Vegas Convention Center.
I traded my 3XL-15Ds for 2 3XL-12Ds back in october and looks like i made a good choice, plus i just did not have the volume for the 15s and my son still be able to ride with me :)
I am pretty sure I have a Clarion HU under the tree (don't let my wife know lol) and I think i am ready to move on with this install.
My first concern is that lately i have noticed a dimming in my headlights and dash lights when i roll up more than one window at a time. Also if the factory system is turned up enough at idle the clock on the radio dims.
Comments or Input on this?
Also a link that could be helpful to some people when trying to figure amps needed from your alt. Not sure if this is accurate or not Swez? Victor? Anybody?
http://www.powerbassusa.com/tech/power_requirement.html
swez on 12/5/2006 18:50:36
Yes, that article is a good read and accurate guide to powering amps properly. Good find!
As for light dimming issues mentioned, it might be a good idea to have your electrical system checked out for performance issues. That will give you a good idea how much current the stock system can handle w/o some considerable upgrades.
Many GM V-6's use a stock 105A ALT and about 600 CCA rated BAT. However, at idle speeds, ALT output is about 50% of that max power rating and can explain part of the light dimming with windows. Minor dimming at idle would be considered normal. (Especially if your heater and rear window defogger are in use) These devices draw a good deal of current when used.
The factory HU issues noted are also normal to a degree. The more bass boost used, the more the HU lamps will dim on heavy bass hits.
FYI: You can get your electrical system checked at most any good autoparts store for free. Many have portable testers that can be wheeled out to the parking lot and check right on the spot. I would not be too surprised if you may have a weak BAT or perhaps one leg of the ALT windings are a mite low.
In any event, plan on the Big 3 wiring upgrade and probably a H.O. aftermarket ALT and a stronger BAT were needed to power a couple of strong amps.
Say more about the amps you are planning to use to power that pair of subs and also your Mids/highs OK?
Swez
cplkittle on 12/6/2006 00:52:01
GM factory batteries suck.
Everytime I install a video system in a brand new GM vehicle, in the 1-1.5 hours I am working on it with the doors open, the battery goes dead.
I would start with a Optima yellow top, and go from there. Take it one step at a time.
Colt45 on 12/6/2006 13:06:10
Well for now I am just going to install the bass portion because the factory mids and highs are pretty good and i want to replace everything so i am going to wait awhile on those.
As for the amps to power the subs i have not decided yet. I just read yesterday about the pairing of subs and amps of the same brand in another post. I was thinking of going with their amps but i am not sure which one. I will include some links to a few for you.
Would it be better to power both subs from 1 mono class d amp or have an amp for each sub, or would that just be a preference thing.
Thanks for the input cplkittle that is what I was wondering if i should do first or exactly how i should begin the process of this electrical upgrade. I imagine it still has the original battery on it also as I have not replaced it but I purchased the car used in Feb. 2005.
Comments? Questions? I may have some answers :)
Colt45 on 12/6/2006 13:11:25
Hehe sorry I forgot the links.
Now these are Powerbass amps but I am open to suggestions if you can show me a better combination for these subs.
http://www.powerbassusa.com/products/amplifiers/xa_class_d.html
Link shows all the amps but the subs with their stats are here so you can see.
http://www.powerbassusa.com/products/subwoofers/3xl_subwoofers.html
I now have a pair of 3XL-12Ds
swez on 12/6/2006 15:21:44
A single XA 1500D makes sense to power both subs. It's rated at 1500 watts RMS @ 1 ohm loads and that is plenty of power for a pair of 3XL-12D's. Yes, they can take more power, but you won't hear the difference and 1 amp of this power will be more than enough to tax your stock electricals already, much less a full range amp later. ;-)
Swez
Colt45 on 12/6/2006 18:29:49
So with that XA 1500D what kind of electrical upgrades do you think i may need. I know a yellowtop optima, probably a Big 3. Am I getting warm here?
Do you think that amp is a good match for those subs?
swez on 12/6/2006 19:00:05
Depends on how you plan to use it Colt. This amp will draw over 100A's of current at full power. So, the Big 3 and a solid battery is a for sure thing.
Also, plan ahead here too for that full range amp. I would say 40-60 A's more on that as well. That means a min wire gage of #2 and if you really wish to do it well, drop to 1/0 and a D-block too.
One thing I did not note on PB products, they don't have list amp and sub manuals on that site. I cannot tell if you'll need a fused D-block or of the amp already has fuses in it already???
Since you are still in the planning stages, consider looking for a H.O. ALT in the near term. You may not need it with just the sub amp... but will need it when adding a full range amp.
http://www.motorcityreman.com
Swez
cplkittle on 12/6/2006 19:16:44
The amplifiers are fused. You will never tell by the pictures because 99% of all amplifiers on the market are overrated, and the fuse ratings give the power capacity away, Thus the side of the amplifier with the fuses is never shown.
If you want to fuse them anyway, here is a cool way to do it for a few extra $$.
http://cgi.ebay.com/Stinger-SHDA2-fused-digital-readout-distribution-block_W0QQitemZ9717572254QQihZ008QQcategoryZ50550QQrdZ1QQssPageNameZWD1VQQcmdZViewItem
This is a fused 2 way distribution block with LED & digital readouts for current draw (amperage) or voltage. I used to use one of these. They are pretty cool.
The MIDI fuses (hidden under the digital readout) range in size from 30 - 150 amps.
Colt45 on 12/7/2006 11:20:43
i can get all that info on the amps and subs from Powerbass and the Powerbass dealer I know. I am pretty sure the dealer has already gotten the info for me I just have not picked it up yet. If I remember correctly the dealer thought the 1500 had 4-30 fuses or 4-40 fuses but he was not sure that why he got the info. i seen the 900D amp in person and it had 3-30 fuses.
swez on 12/7/2006 20:47:40
Basic calculations suggest 120 A's for fusing is about right. It really depends on amp efficiencies and supply voltage the amp can obtain from the electrical system.
Output watts/input supply voltage = amperage draw @ full power:
1500/14.4 = 104 A's
1500/13.5 = 111 A's
1500 /13.0 = 115 A's
1500/12.5 = 120 A's
cplkittle on 12/7/2006 20:59:37
ok, I got bored and wanted to do some math...
you asked the difference between 2 15's and 2 12's
in terms of surface area, here's how everything stacks up:
one 15" sub = 1.5625x12" subs = 2.25x10" subs = 3.515x8" subs
two 15" subs = 3.125x12" subs = 4.5x10" subs = 7.03x8" subs
three 15" subs = 4.6875x12" subs = 6.75x10" subs = 10.54x8" subs
four 15" subs = 6.25x12" subs = 9x10" subs = 14.06x8" subs
one 12" sub = 1.44x10" subs = 2.25x8" subs
two 12" subs = 2.88x10" subs = 4.5x8" subs
three 12" subs = 4.32x10" subs = 6.75x8" subs
four 12" subs = 5.76x10" subs = 9x8" subs
one 10" sub = 1.5675x8" subs
two 10" subs = 3.125x8" subs
three 10" subs = 4.6875x8" subs
four 10" subs = 6.25x8" subs
Thanks
Replies (27)
Victor on 09/26/2006 17:50:25
what sub is this???
Colt45 on 09/26/2006 18:00:36
It is a Powerbass 3XL-15D Something new i am trying out
Victor on 09/26/2006 18:06:30
do u ahve yahoo, msn or skype realtime messengers?? if yes.. my id on yahoo is victorginger
msn is victorexports@hotmail.com
skype is victorginger
its much better to take this online.
Colt45 on 09/26/2006 20:58:40
any other opinions on this?
Victor has been helping me but i would like others opinions also
swez on 09/27/2006 08:46:22
Looks like a pretty strong woofer here Colt: This one?
http://www.audio-warehouse.com/web/mdl/3XL-15D/detail.asp
Do you have a mfg's link to enclosure and specs on them? A few guys have mentioned Powerbass subs here in the past few months and from the general specs noted, this sub can take some serious power and very efficient too. These are specs we see in Pro line Sound Reinforcement woofers.
3" voice coil
1+1 DVC
1000 Watt (RMS)
Sensitivity: 93dB SPL @ 1w/1m
General thoughts: Since this sub likes huge ported boxes and are very efficient already, I would seriously consider a single sub/amp pairing here. I see a potential of 150 dB + bass engine here already with just 1 sub and amp. A box of this size and porting needs will probably weigh close to 300 lbs alone. (1" MDF box panels, 1.5" speaker mounting panel and 5/8" thick port material)
Trunk space avaialble in this car is what? I have some concerns about getting this size enclosure into the trunk. One has to consider the "mouth opening" dimensions of the trunk here too. What good is it to build a great box and not be able to fit it into the car??? Want to avoid that scenario right?
Height: 18" min?
Width: Max wide to work with... don't forget the wheel wells cut space
Depth: Max depth available
Port tuning freq: Got a target here yet?
Box area calculations:
H x W x D/1728 = # of cubic feet externally, the box will take up physically.
For internal cf numbers, we have to consider the wood thickness used for the box, woofer & port displacements as well.
Comments?
Swez
Colt45 on 09/28/2006 15:20:31
I have been mulling over the box size:trunk size problem for the past few days. I really would like to get both subs into the car.
Is it possible to build the box inside of the car?
Yes I do have the TH Parameters for these subs in a pdf format and can email them to you if you like.
I dont understand about the ports i guess. 5/8" material not sure what you mean by this.
Have seen 2 of these subs installed in a 1996 toyota celica before. Not sure what type of box they had though. May have been a sealed box but the manufature gives a warning not to put them in sealed boxes. I am not sure why i am sure that you could probably tell me.
I have no idea about port tuning frequency ??
Have built a few boxes before but never to any specs like i am wanting to do now. Just built them to fit in the space that was needed and to accomodate the speakers.
Ummm
about 36" wide
i am thinking of laying the back seats down to be able to get more depth?? About 36" with the seats up
and height about 16 - 17"
swez on 09/28/2006 19:23:54
If using a sloted port/vent here, the port/vent wood thickness can be 5/8" thick to cut down on weight and space these segments take up in the box. The other option is just using 4" round ports to the proper length. These can be of PVC drain pipe and easily cut and glued to fit.
Building a box inside a small sedan... I wouldn't even entertain that thought. Maybe Paul Tuttle Jr. would... but Paul Sr. would have a stroke over that one.
Lets see... about how large a 5 cf box would be based on your given dimensions:
Max Height: 17"
Max Width: 36"
Max Depth" 20"
Board thickness: 1.0"
This nets an internal airspace of 5.3 cf. Then we have to subtract the woofer and port displacements to get as close as possible to your target 5.0 cf internal.
Now, for a pair of these subs, we'll just change a few basic parameters and see what that looks like. This would be 2 boxes, side by side,
Hmax: 17"
Wmax: 35"
Dmax: 39"
This nets a box with 10.6 cf internal and by the time we subtract subs, ports and divider board displacements, you'll be pretty darn close to a nut busting 10.0 cf.
Can you imagine getting a box of that size, into the mouth of this trunk? Make a card board proof of this domension and see.
Swez
Colt45 on 09/28/2006 19:35:12
well Swez my man I am sure gonna try it
the subs take up approx 1/4 cu ft (just found that out)
so i should build a box with 2 seperate compartments?
will there need to be a port in each compartment, i assume so
making it out of cardboard is a good idea never thought of that and i am going to try it if i can find enough cardboard. lol
i love doing this stuff :)
Colt45 on 09/28/2006 19:47:33
oh can i build the 2 seperate boxes, get them in the car and then put them together?
oh and this is the specs they give on optimum ported volume
Gross Vb internal 5.0 cu ft have been told by Victor i should be about 5.4 cu ft
Circular Port 6" x 7.5" D
Fb (Box Tuning) 40Hz
F3 (-3dB Cutoff) 33Hz
Pe (Watts-RMS) 250-500 Watts
Subsonic Filter Setting if applicable 35 Hz What exactly is this?
swez on 09/28/2006 22:03:49
Yeah.... cardboard cut-outs mang. Just like in model making classes. It gives a good idea of the over all foot print and how much space they will take up.
Yes, I would definitely consider building this system in matched, dual boxes. This makes them easier to handle, install and building them is just a tad more work.
Circular Port 6" x 7.5" D (Porting dimensions)
Fb (Box Tuning) 40 Hz. = (Port tuning frequency target, based on internal box volume, minus sub and port displacements)
F3 (-3dB Cutoff) 33Hz. = (Lowest frequency subs will reach with usable SPL levels
Pe (Watts-RMS) 250-500 Watts = (Average power levels sub can work with)
Subsonic Filter Setting if applicable 35 Hz. What exactly is this?
(SSF or infrasonic filters are used to protect the woofers from damage at frequencies below Port tuning) When using high powered ported/vented enclosures, we must use these filters to keep the sub cones from "unloading", (going out of control) below tuning point.
These are all speaker/sub specifications a design engineer uses to calculate the performance characteristics of a given speaker/sub in various enclosure types.
FYI: With a Vb of 5.0 cf, a 6" dia, port of 7.5" nets a tuning frequency of 36 Hz. Not a bad place to be at all.
swez
Colt45 on 09/29/2006 11:36:45
if you were to just guess what kind of spl numbers do you think you could get from this setup?
and what do you think the difference would be from having a single sub or 2 subs
that is if these boxes are to specs just like the numbers show
swez on 09/29/2006 12:54:29
Your SPL numbers with one well designed box, 1 strong sub and 1000 watts RMS should put you pretty close to 150dB. Sound dampening doors and other panels will bring that number up as well.
If you went with 2 of everything, the SPL number would be about 3-5 more dB of SPL. Is that really worth all the extra cash, efforts and electrical upgrades that would go with it??? Only you can say.
Basically, this is one very efficient sub. (93dB @ 1 watt/1meter... assuming this is accurate) Most subs range from 85-88dB SPL @ 1w/1m. With ported enclosures, we can pick up 4-6dB SPL more, at the Port Tuning Frequency point and points 1/4 octave above PTF.
Also, if we double the amping power and add a 2nd sub, we get about +3 dB more bass in sealed enclosures. In ported sub enclosures, we might see +4 to +6 dB more SPL.
Now comes the real kicker... "Cabin gain affect"! In a larger vehicle, bass couples with the cabin and we can get a whopping +10 to +15dB more SPL at cabin resonance frequency. This is free and all we need do is enjoy and design for that added bump.
In smaller vehicles and single cab trucks, the cabin gain often much less. So, to hit high SPL #'s here, we have to seal the cabin as tightly as possible and use expensive power amps and subs to get the same net output levels.
Think this one through Colt... I really think you can get very good results with just one amp, 1 sub and a well designed ported enclosure. If this were not so, I would not put that in writing bud!
FYI: After serving this forum for 8 years now and doing Pro Sound projects for over 10 years now, there's a lot more to know than anyone can write in a few paragraphs.
Victor and I are giving you just the basics at this point. It's done that way for a very good reason too. What good would it be to hand you a 50 page tuitorial, written at engineering grade levels and have you get stuck on page 2? Suffice to say, we could easily do the A-Z, What... How and Why dog and pony show... but if the reader cannot understand it all, what's the point?
So, for now... we are giving you a small slice of the WHAT and HOW aspects to consider. The WHY is important, (to be sure) but it makes little sense to load ya down with technical theory, complex math equations and the like.
If one has an engineering background, then a debate would ensue. But at least then, we'd all be talking roughly the same language and the debate would be an exchange of cogent ideas and applied science.
Nuff said... COFFEE
swez
PS Where to next Kimosabe?
Colt45 on 09/29/2006 13:22:40
Ok now you about have me convinced to use just one 15" sub but before i make that decision i have a question for you.
Here are the specs for the same line of sub but 12"
Gross Vb Internal 2.0 cu ft
Circular Port 5" x 14.75 " D
Fb (Box Tuning) 38 Hz
F3 (-3db Cutoff) 32 Hz
Pe (Watts-RMS) 250-850 Watts
Subsonic Filter Setting 35 Hz
That is for each sub.
Would 2 of these subs produce about the same SPL as one 15" sub?
Would it be better to go with these?
swez on 09/29/2006 16:15:38
That's a fair question and trig/calc were not my strong suits in school...
If it happens to be yours, measuring the total "surface area" of each cone size from the surrounds' edge to the voice coil would give you one part of the equation. The other parts are to know the X-max of the 12 and 15 subs and also factor in effeciency numbers.
I have heard a few guys say... "The cone size of a typical 15" sub is about equal to a pair of 12" subs of the same family". Is that 100%, 50% or not even close to accurate? I dunno?
However, what we do know is that if we double the cone radiation area from "X" to "X sq'd" we pick up +3dB, as long as the power input is the same and so is the efficiency.
If we looked at the eff rating of the 15 VS the 12's and that # is +3dB or higher, cone area is often the key reason. Here, we excite a larger cone with the same electrical power applied and because the cone area is larger in the 15" cone, we move more air and a larger pressure wave. Hense, more SPL. (A measure of pressure levels from a given transducer... SPL = Sound Pressure Level)
Not sure if that answers the question or raises more questions, but those are the basic principles at work in speakers and woofers.
Care to take a stab at the math? We want to compare the radiating area of a 12" vs a 15" sub cone. Admittedly, I slept through the advanced math classes like Trig & Calc. D'oh... where's my dunce cap? ;-(
Swez
swez on 09/30/2006 10:46:48
OK, sounds like you and Victor had a YIM chat last night... what was the general concenses of your chat?
swez
Colt45 on 12/5/2006 16:53:37
Well I am back from a break away from the cones and amps, wires and voltage and have found some interesting news.
Las Vegas, NV (Nov 2, 2006)—Competing in a field that included nearly 2,000 new products from numerous different companies, PowerBass was the proud recipient of two International New Product Awards at the 2006 SEMA Show. The PowerBass 3XL-12D subwoofer was selected for top honors by the editors of Automaxx magazine of the Netherlands and Car Stereo Tuning of Brazil. Only a handful of other car audio products received recognition at the awards ceremony held November 1st at the Las Vegas Convention Center.
I traded my 3XL-15Ds for 2 3XL-12Ds back in october and looks like i made a good choice, plus i just did not have the volume for the 15s and my son still be able to ride with me :)
I am pretty sure I have a Clarion HU under the tree (don't let my wife know lol) and I think i am ready to move on with this install.
My first concern is that lately i have noticed a dimming in my headlights and dash lights when i roll up more than one window at a time. Also if the factory system is turned up enough at idle the clock on the radio dims.
Comments or Input on this?
Also a link that could be helpful to some people when trying to figure amps needed from your alt. Not sure if this is accurate or not Swez? Victor? Anybody?
http://www.powerbassusa.com/tech/power_requirement.html
swez on 12/5/2006 18:50:36
Yes, that article is a good read and accurate guide to powering amps properly. Good find!
As for light dimming issues mentioned, it might be a good idea to have your electrical system checked out for performance issues. That will give you a good idea how much current the stock system can handle w/o some considerable upgrades.
Many GM V-6's use a stock 105A ALT and about 600 CCA rated BAT. However, at idle speeds, ALT output is about 50% of that max power rating and can explain part of the light dimming with windows. Minor dimming at idle would be considered normal. (Especially if your heater and rear window defogger are in use) These devices draw a good deal of current when used.
The factory HU issues noted are also normal to a degree. The more bass boost used, the more the HU lamps will dim on heavy bass hits.
FYI: You can get your electrical system checked at most any good autoparts store for free. Many have portable testers that can be wheeled out to the parking lot and check right on the spot. I would not be too surprised if you may have a weak BAT or perhaps one leg of the ALT windings are a mite low.
In any event, plan on the Big 3 wiring upgrade and probably a H.O. aftermarket ALT and a stronger BAT were needed to power a couple of strong amps.
Say more about the amps you are planning to use to power that pair of subs and also your Mids/highs OK?
Swez
cplkittle on 12/6/2006 00:52:01
GM factory batteries suck.
Everytime I install a video system in a brand new GM vehicle, in the 1-1.5 hours I am working on it with the doors open, the battery goes dead.
I would start with a Optima yellow top, and go from there. Take it one step at a time.
Colt45 on 12/6/2006 13:06:10
Well for now I am just going to install the bass portion because the factory mids and highs are pretty good and i want to replace everything so i am going to wait awhile on those.
As for the amps to power the subs i have not decided yet. I just read yesterday about the pairing of subs and amps of the same brand in another post. I was thinking of going with their amps but i am not sure which one. I will include some links to a few for you.
Would it be better to power both subs from 1 mono class d amp or have an amp for each sub, or would that just be a preference thing.
Thanks for the input cplkittle that is what I was wondering if i should do first or exactly how i should begin the process of this electrical upgrade. I imagine it still has the original battery on it also as I have not replaced it but I purchased the car used in Feb. 2005.
Comments? Questions? I may have some answers :)
Colt45 on 12/6/2006 13:11:25
Hehe sorry I forgot the links.
Now these are Powerbass amps but I am open to suggestions if you can show me a better combination for these subs.
http://www.powerbassusa.com/products/amplifiers/xa_class_d.html
Link shows all the amps but the subs with their stats are here so you can see.
http://www.powerbassusa.com/products/subwoofers/3xl_subwoofers.html
I now have a pair of 3XL-12Ds
swez on 12/6/2006 15:21:44
A single XA 1500D makes sense to power both subs. It's rated at 1500 watts RMS @ 1 ohm loads and that is plenty of power for a pair of 3XL-12D's. Yes, they can take more power, but you won't hear the difference and 1 amp of this power will be more than enough to tax your stock electricals already, much less a full range amp later. ;-)
Swez
Colt45 on 12/6/2006 18:29:49
So with that XA 1500D what kind of electrical upgrades do you think i may need. I know a yellowtop optima, probably a Big 3. Am I getting warm here?
Do you think that amp is a good match for those subs?
swez on 12/6/2006 19:00:05
Depends on how you plan to use it Colt. This amp will draw over 100A's of current at full power. So, the Big 3 and a solid battery is a for sure thing.
Also, plan ahead here too for that full range amp. I would say 40-60 A's more on that as well. That means a min wire gage of #2 and if you really wish to do it well, drop to 1/0 and a D-block too.
One thing I did not note on PB products, they don't have list amp and sub manuals on that site. I cannot tell if you'll need a fused D-block or of the amp already has fuses in it already???
Since you are still in the planning stages, consider looking for a H.O. ALT in the near term. You may not need it with just the sub amp... but will need it when adding a full range amp.
http://www.motorcityreman.com
Swez
cplkittle on 12/6/2006 19:16:44
The amplifiers are fused. You will never tell by the pictures because 99% of all amplifiers on the market are overrated, and the fuse ratings give the power capacity away, Thus the side of the amplifier with the fuses is never shown.
If you want to fuse them anyway, here is a cool way to do it for a few extra $$.
http://cgi.ebay.com/Stinger-SHDA2-fused-digital-readout-distribution-block_W0QQitemZ9717572254QQihZ008QQcategoryZ50550QQrdZ1QQssPageNameZWD1VQQcmdZViewItem
This is a fused 2 way distribution block with LED & digital readouts for current draw (amperage) or voltage. I used to use one of these. They are pretty cool.
The MIDI fuses (hidden under the digital readout) range in size from 30 - 150 amps.
Colt45 on 12/7/2006 11:20:43
i can get all that info on the amps and subs from Powerbass and the Powerbass dealer I know. I am pretty sure the dealer has already gotten the info for me I just have not picked it up yet. If I remember correctly the dealer thought the 1500 had 4-30 fuses or 4-40 fuses but he was not sure that why he got the info. i seen the 900D amp in person and it had 3-30 fuses.
swez on 12/7/2006 20:47:40
Basic calculations suggest 120 A's for fusing is about right. It really depends on amp efficiencies and supply voltage the amp can obtain from the electrical system.
Output watts/input supply voltage = amperage draw @ full power:
1500/14.4 = 104 A's
1500/13.5 = 111 A's
1500 /13.0 = 115 A's
1500/12.5 = 120 A's
cplkittle on 12/7/2006 20:59:37
ok, I got bored and wanted to do some math...
you asked the difference between 2 15's and 2 12's
in terms of surface area, here's how everything stacks up:
one 15" sub = 1.5625x12" subs = 2.25x10" subs = 3.515x8" subs
two 15" subs = 3.125x12" subs = 4.5x10" subs = 7.03x8" subs
three 15" subs = 4.6875x12" subs = 6.75x10" subs = 10.54x8" subs
four 15" subs = 6.25x12" subs = 9x10" subs = 14.06x8" subs
one 12" sub = 1.44x10" subs = 2.25x8" subs
two 12" subs = 2.88x10" subs = 4.5x8" subs
three 12" subs = 4.32x10" subs = 6.75x8" subs
four 12" subs = 5.76x10" subs = 9x8" subs
one 10" sub = 1.5675x8" subs
two 10" subs = 3.125x8" subs
three 10" subs = 4.6875x8" subs
four 10" subs = 6.25x8" subs
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