multiple subs

**BobEllis** · 15 August 2013, 11:14 Thursday

You should be able to use a splitter from each output on the receiver to feed each pair of subs. For example: http://www.parts-express.com/pe/show...number=240-127

The only problem could be if your sub amps have particularly low input impedance that the Denon cannot handle. This is not likely, but if you hear a lot of distortion with the pair of amps connected and it goes away when you disconnect one, then you need to add a buffer.

I'd go with separate boxes for your new build, based on the Harmon white paper on sub placement. I've found two subs place asymmetrically worked quite well. I had one front and almost centered, one on a side wall. The Harmon paper suggests one centered on each wall or one in each corner for 4 subs. http://www.harman.com/EN-US/OurCompa...s/multsubs.pdf

For an "ultimate sub system", you might consider DSP EQ of some some sort, on a per sub basis. Room EQ Wizard will output filter controls for a Behringer FBQ2496 Feedback Destroyer Pro through midi, which makes proper EQ easy. It is a 2 channel device, so you'd only need 2 with 4 subs. You could try it with subs connected and EQd on a pair basis, too. Another option is www.minidsp.com. REW can't control it, but the software makes it pretty easy to add the filters you need.

Enjoy the build.

**crytklmass** · 15 August 2013, 12:50 Thursday

Thanks for your reply. The other 2 subs are a DIY Dayton 15" Titanic MK 4 1,000 watt and a B&W AS855 15" sub 1,000 watt
Those 2 are plate amps of course, the 2 12"s will be passive. Do you both channels on my crown xls 1500 ch. 1 for sub 1 and ch 2 for sub 2 OR just use a single channel to both subs using speaker wire? (I never used a passive amp before) Im using RCA to connect the crown to my sub 2 output, then I assumed I would use the speaker wire to my subs, NOT an RCA cable like to do with plate amps. Is that correct?

Here are the sub specs:
Specifications: • Power Handling: 120 watts RMS/180 watts max • VCdia: 2" • Le: 1.31 mH • Impedance: 8 ohms per coil / 4 ohms total • Re: 3.0 ohms • Frequency range: 25-1,000 Hz • Fs: 27 Hz • SPL: 93.5 dB 2.83V/1m, 90.5 dB 1W/1m • Vas: 4.34 cu. ft. • Qms: 3.44 • Qes: 0.38 • Qts: 0.34 • Xmax: 7 mm • Dimensions: Overall Diameter: 12-3/8", Cutout Diameter: 10-3/4", Mounting Depth: 6".

Dayton SD315-88 12" dvc subwoofer

They were free from a friend, I assume they are descent subs....

I looked at the rear of my B&W subs, its using a monster RCA cable however, where it connects on my sub it have a splitter connected to my L & R inputs? then its terminated? is the terminated plug used to daisy chain subs? could I daisy chain from my B&W to my 15" Dayton? on my Dayton I used the RCA LFE direct. Should I change it to my L & R? what is the difference?

**J-Dub** · 15 August 2013, 18:02 Thursday

Hi Bob,
They are decent subs but don't have a lot of excursion. Some guys here would be happy to help you design a box for them. Just don't expect to blow the house down with them. Not going to happen here. However, having 4 subs in a room will certainly give you a huge bonus on the lower end if placed right.

OK to answer the questions. These are 4 ohm subs each so you cannot put 2 of them on the same amp output with out some fancy wiring. They are DVC wich will allow this but lets keep things simple... Connect a splitter from the output of your denon AVR using an RCA cable. Use RCA's from the outputs of the splitter to your amps. One to the first plate amp, one to the second plate amp and one to each input of your Crown amp. Make sure you are splitting the "sub output" not the record output from the denon. ( The crown amp most likely doesn't have a low pass filter so use the sub out put of the denon.) Your crown amp should have 2 speaker outputs. So connect speaker wire, preferrably 16 guage or 14 guage, from each speaker output to each sub using binding posts. Also make sure your crown amp is 4 ohm stable. Look on the back and there should be a line saying stable to "X" ohms. Don't go lower than it says. Most likely it will handle 4 ohms fine.

Now for your DVC drivers. They are "dual voice coil" meaning they will have 2 positive terminals and 2 negative terminals each. You want to connect the voice coils in parallel. look this up on google for pictures, but essentially you are just splitting the positive to both terminals and then splitting the negative to both terminals on each speaker. I would just run 2 positive wires from the back of the positive binding post to the 2 positives on the driver and then do the same with the negatives.

**J-Dub** · 15 August 2013, 18:25 Thursday

Off the top of my head, a sealed box with INTERNAL dimentions roughly 20"W x 20"H x 19"D will get your internal volume to 4.4 cubic feet. pretty close to the vas of the driver. That would be an easy box to build as a starting point. I haven't modeled it but I'm sure someone will chime in and give you something a little better suited to the TS parameters here in a little bit.

**crytklmass** · 15 August 2013, 19:58 Thursday

That sounds great J-Dub. I was wondering why it had 2 pos and 2 neg posts. I thought I could just use either one. But I assumed they were there for a reason. Ill build 2 boxes like you suggested and connect them per your instructions. That sounds pretty simple. There being used behind my seats, basically as rear subs. the 2 15"s up front will take most of the work.

I found this picture, is step 3 Correct? I connect the speaker + terminal to - and the other - to + ?? basically crossing them speaker wire inside the box? sorry, I just want to verify, I don't want to blow my Crown amp or the speaker.

http://www.ehow.com/how_4924876_hook-up-dual-ohm-subwoofer.html

Connect a piece of speaker wire between the "+" terminal of the second set of speaker terminals and the "-" terminal of the first set. Connect a piece of speaker wire between the "-" terminal of the first set of terminals and the amplifier.

**J-Dub** · 16 August 2013, 16:40 Friday

Hey Bob, You could do that and not hurt your amp but not recommended. That would put you at a 16ohm load for each sub and lower your output significantly. Being that you have a very powerful amp for these subs it would work fine but I don't recommend.

When building your subs, Put 2 binding posts on the cabinet. (+ and -) From the positive inside the cabinet, connect 2 red wires for positive and run one to each of the positives on the driver. Then from the negative inside the cabinet, run 2 black wires from the negative binding post, one to each of the negatives on the driver. The posts on the driver are usually bigger to indicate the positives or sometimes have a red dot painted on them and sometimes they are labeled "+" for positive. The way described above in your link is for "series" wiring. We want to do "parallel" wiring.

Also, be careful of car audio websites, most of the time car audio DVC drivers are 2 ohms per coil. Your drivers are 8ohms per coil. Look at this website for valuable information on wiring, box volume calculators, port tuning and all kinds of goodies that will help you out. It is a car audio site but its calculators and wiring diagrams are extremely beneficial. http://www.the12volt.com/info/diagrams.asp

Scroll down just a tiny bit and look at the links under "Browse by category." You can play with the calculators to get an idea of how things work and read up on series and parallel wiring. There are calculators for series and parallel wiring also. Remember, your DVC drivers are "dual voice coil" meaning they are essentially 2 drivers in 1. So think of each speaker as 2 speakers. each voice coil is 8 ohms, so when playing with the calculator, you will put in 2 speakers at 8 ohm each. in parallel you should come up with a 4ohm load and in series you should come up with 16ohms. You want to stay between 4ohm at the lowest and 8 ohm at the highest. 16 will work without damage to almost any amp but you loose power. NEVER go below 4 ohms unless you are using a car amp to drive the speaker you designed. Most car amps are 2ohm stable and some can handle down to .5ohm resistance.

Reference the aforementioned website when building your subs, there is an abundance of useful tools there to help you along the way.

**crytklmass** · 16 August 2013, 23:15 Friday

Thank you for clearing that up J-Dub... That diagram just didn't look correct to me.

Here is what started all this... I built some clone QSC 2150 speakers. All the part are OEM, I just built the box. It was being powered my Denon 4311CI.... My friend decided he wanted to start his own DIY project so he purchased the 2 Dayton 12" subs and was going to power them passively with his crown amps but then decided it was too much hassle and owed me money so he gave me the 2 12" woofers and 2 Crown XLS 1500 amps. However I considered finishing his project but I could use his crown amps to power my QSC 2150 Front left and Right, Use one channel on the 2nd crown amp to power my center and just purchase 2 more plate amps which I could run with the Y cable.

These are the crown specs:
its 300w @8 ohms, 525w @4 ohm bridged is 1550w @4 ohm 1050w @8 ohm.
I would like synergy of both crown amps but don't need 1,000w plus to my center speaker

The SC 2150 is an OEM clone, Here are the specs

UltraDNS Client Redirection Service

http://qsccinema.com/products/loudspeakers/dcs-3-way-systems/

Sorry things got crazy, I think I jumped ahead of myself before I considered all the options.

**J-Dub** · 09 September 2013, 16:29 Monday

Unless you have independent gain control of each channel on each crown amp I would not use the free channel to power your sub. Since the center is already on one channel you will not be able to sync up the sound level of the sub. If you do have independent gain it might work but still not really recommended. Use 2 plate amps, one in each enclosure. This will be a 4 ohm load in each box for each amp if you run dvc's in parallel. If you must use one amp, it will be some tricky wiring to a novice. You would have to do combination series-parallel wiring. The dvc's would be run parallel and each box would be in series bringing you back to an 8 ohm load. I don't think i could possibly put this into words. I could only demonstrate it. Either way, sorry for taking so long to reply. good luck with your project and let us know if you need anymore help!

**crytklmass** · 10 September 2013, 21:06 Tuesday

Originally posted by J-Dub

Unless you have independent gain control of each channel on each crown amp I would not use the free channel to power your sub. Since the center is already on one channel you will not be able to sync up the sound level of the sub. If you do have independent gain it might work but still not really recommended. Use 2 plate amps, one in each enclosure. This will be a 4 ohm load in each box for each amp if you run dvc's in parallel. If you must use one amp, it will be some tricky wiring to a novice. You would have to do combination series-parallel wiring. The dvc's would be run parallel and each box would be in series bringing you back to an 8 ohm load. I don't think i could possibly put this into words. I could only demonstrate it. Either way, sorry for taking so long to reply. good luck with your project and let us know if you need anymore help!

Yep, there's been a change. My friend wanted his 12's back, guess he's giving in another go. So I was thinking of building 2 Passive 15's (Dayton or other brand) OR 2 18" Dayton or other brand. Since they will be passive which sub will be the best match for my 2 existing 15"s? (1 is the dayton Titanic MK4, the other is B&W 855) Should I stay consistent and build 2 15's or build 2 18's and have 2 15's? The 2 15's I have now are not producing enough bass for my licking. In their defense they are on a basement floor (finished with laminated wood, no walls yet, just recently started framing). Eventually they will be in their own room. Roughly 16 W, 18 D, 8' ceiling. So, do I stick with 2 more Dayton 15's or Dayton 18's or another brand. Sealed subs powered by the 2 crown amps. 1050W @ 8 ohms, and 1,550W @ 4 ohms bridged.

Whatcha think?

multiple subs

multiple subs

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