[brother love]

Looking for suggestions on how to implement a cheap & cheerful (3) subwoofer/ digital signal processor (as req'd)/ etc. arrangement in with my existing 2 channel rig, & most importantly, how to best connect the whole ball of wax.

[Note: I searched previous subwoofer swarm threads by Rclark & others, but didn't see how to best hook it all up].

Tentative plans are to purchase (3) used heavily discounted subs off of local Craigslist to experiment with. A miniDSp, Behringer or some other digital signal processor I assume may be needed; or I also need a used amp(s).

Primary objective: fill in 45-65 Hz suck-out from existing room/ system set-up (my room measurements/ adjustments/ treatments outlined here: http://www.audiocircle.com/index.php?topic=133947.0 ).

Existing system:  GR Research N3 transmission line speakers, TBI MIllenia MG3 amp (2 channel, no sub out), Grant Fidelity TubeDAC-11 preamp, Mac Mini dedicated music server, Oppo BDP83SE bluray

(3) subwoofer swarm strategy:

Employ Earl Geddes subwoofer swarm methodology (the way I understand it from research): run speakers full range (40 Hz - 3db), add a powered 12" sub near speakers in corner,  add a powered 10" midway on opposite wall of main speakers, add a powered 10" subwoofer in a corner farther away from other 2 subs & possibly elevated as necessary. Regardless of initial sub locations, take room measurements & adjust along the way to get best results.

In the simplest manner possible, how could I hook-up all 3 subs into the existing system without significant degradation to the existing 2 channel rig?

Examples: Can I cable all the subwoofers in series (in of 1st sub, out to the 2nd sub, etc., then out of 3rd sub into 2 ch amp w/ downside being mains are at sub crossover setting) ? Is there a 3 way or 4 way splitter rca cable or box contraption to consider?  Can I use Y splitters off 1 channel of an amp for mono signals? 

I know that I could use a mini DSP digital signal processor, but my understanding is that it would degrade the sound of the 2 channel amp/ full range speaker mains to do so. The 2 in x 4 out miniDSP is cheap & cheerful at $105, but price kicks up quite a bit to add more outputs.

I could also go the passive bucket sub route & utilize an amp to handle 3 mono channels, but I assume feed to mains would be above a crossover setting for the subs. This option starts getting pricy though ...

So what do you think, can a subwoofer swarm be added on a shoestring budget to an existing mid-fi 2 ch rig ?  Or am I delusional ? 

[mresseguie]

Brother love,

After reading your post, the first question I thought of was, "What's your budget?" Then, I immediately thought of a cheap DIY subwoofer that was talked about here on AC. I have not tried this myself, but I keep thinking about slapping together two for my son's system.

Here's the link to the AC thread and below that the link to the earlier thread on The Horn Shoppe Forum:

http://www.audiocircle.com/index.php?topic=119271.0

http://thehornshoppeforum.com/index.php?PHPSESSID=rmd6f9e51cnovgme6b8t2i2hc6&topic=406.0

I hope this works for you. Enjoy!

[brother love]

Thanks mresseguie, but I am familiar with that option (the passive bucket sub I made mention of at the end of my initial post).

A Crown XLS-1500 amp (currently marked way down due to XLS-1502 coming to market) with (2) of the Peerless 8" speakers with buckets & all the necessary hardware is in the $500 range. Adding another bucket sub & 3 channel amp would drive the price up further ...

(3) used garden variety powered subwoofers off local Craigslist can be had for $100 each or so. This would be to experiment with, not be the end all be all final solution. I can sell the used subs on Craigslist & recover bulk of the money if I choose to go with better quality subs or take a different route.

[mresseguie]

I see I need to either have more coffee before offering a reply, or I need to read an entire post before posting.  LOL!

You are correct about cheap Craigslist subs. They are always in supply in my area (I assume it's the same everywhere).

[brother love]

Hey, it was easy to miss in my long winded post. I'm like you though, in that I am intrigued by the bucket sub. I bookmarked the Transcendent Sound link some time ago where they wrote a review of The Horn Shoppe- Ed Schillings design. He called it redneck sub I believe 

Here's a reference to the subwoofer swarm approach:  https://mehlau.net/audio/multisub_geddes/

I read some about in diyAudio incl. Earl Geddes posts, but too much time is spent arguing the subject:  http://www.diyaudio.com/forums/subwoofers/134568-multiple-small-subs-geddes-approach.html

[JohnR]

I bought two XLS1500 recently and can't believe the price you guys can get them for. So far only one is doing anything but no problems so far. I'd suggest grabbing one, and then looking for (or building) two quality passive subs. I think that will be better (with placement) than three not-so-quality subs. The Crown will drive 2 ohm loads so you could drive up to 4 subs, as long as you don't need independent adjustment of all.

A miniDSP 2x4 could be used between your preamp and the subs, as long as it will drive the relatively low input impedance (7k or so, fine for SS, not so fine for tubes or passive). However, you could start just with placement and gain. FWIW I find all the adjustments with the Geddes method too much to bear, I find one sub in the middle of the front wall gives good results, one on front middle and one on back middle better, and after that it's hard to see a dramatic improvement without going to nearfield dipole subs. (YMMV, JMHO, etc..)

[mresseguie]

Brother Love,

If I had $2400 and if I were a lazy person [My wife insists I am often lazy.], I would call Duke at Audio Kinesis to order his swarm subs. Unfortunately for me, I'm moving to Taiwan on the 13th, so I must seriously downsize everything.

JohnR,

Hi, John. Good suggestion!

Michael

[Poultrygeist]

I use two bucket subs powered by a single Yung SD300 ( a Crown would be better ). I've heard Ed's Crown powered buckets and they were jaw dropping. 

I split the single output on my preamp with a pair of Y cables ( one male into two females ) and feed both the Yung plate amp and my TPA3116 main amp. 

My TPA3116 drives a pair of Fostex single driver speakers in this C&C system.

The bucket subs blend so well you don't know they're there until you turn them off.

If I wanted to add more subs I could daisy chain using the Yung plate amp's line-outs.

[raindance]

I bought two XLS1500 recently and can't believe the price you guys can get them for. So far only one is doing anything but no problems so far. I'd suggest grabbing one, and then looking for (or building) two quality passive subs. I think that will be better (with placement) than three not-so-quality subs. The Crown will drive 2 ohm loads so you could drive up to 4 subs, as long as you don't need independent adjustment of all.

A miniDSP 2x4 could be used between your preamp and the subs, as long as it will drive the relatively low input impedance (7k or so, fine for SS, not so fine for tubes or passive). However, you could start just with placement and gain. FWIW I find all the adjustments with the Geddes method too much to bear, I find one sub in the middle of the front wall gives good results, one on front middle and one on back middle better, and after that it's hard to see a dramatic improvement without going to nearfield dipole subs. (YMMV, JMHO, etc..)

What is the miniDSP 2x4 input impedance?

Agreed that a tube preamp absolutely will not drive a swarm directly - it may struggle with even one plate amp. It will lose both transparency and bass. I'm considering designing a buffer for adding sub out to the average tube amp/preamp.

[raindance]

Looked at the miniDSP specs - input impedance is 6K - this will suck the bass out of your tube preamp and there won't be much need for subs

[brother love]

Thanks JohnR & raindance for info re: input impedance. Geddes recommends a Behringer DCX2496 loudspeaker management system coupled with rack amps/ AVR (like his older Pioneer VSX-919H with preamp outs) to handle a multi-sub system.

Poultrygeist,

What preamp are you using to split the single output to a pair of Y cables for splitting to amp for mains & plate amp for bucket sub pair?  Your prior comments about the buckets subs really left an impression, & high on my list of considerations.

[Poultrygeist]

Thanks JohnR & raindance for info re: input impedance. Geddes recommends a Behringer DCX2496 loudspeaker management system coupled with rack amps/ AVR (like his older Pioneer VSX-919H with preamp outs) to handle a multi-sub system.

Poultrygeist,

What preamp are you using to split the single output to a pair of Y cables for splitting to amp for mains & plate amp for bucket sub pair?  Your prior comments about the buckets subs really left an impression, & high on my list of considerations.

I have the Nobsound NS-01P which uses 3 12AX7 tubes and one rectifier tube. It drives both the TPA3116 and plate amp and has plenty of gain. Check out the reviews on Amazon. Although it's from China the Nobsound is shipped from a warehouse in the US. Gorgeous to look at and hear it sells for around $250.

[Odal3]

The bucket subs blend so well you don't know they're there until you turn them off.

I have more than ones done measurements with REW of some monitors and thinking it sounds pretty nice and didn't realize until I saw the frequency plots that I had forgotten to turn off the bucket subs. Once the buckets were turned-off, the sound was thin and it definitely feel like something is missing. You can't really call the bucket subs a HT subwoofer monster aimed at movies, but for music, they are great!

Yes, they are ugly, but they are so small it easy to hide them, or you can do like Poultrygeist and spend a little bit extra time and make them in pianoblack and chrome. PG - do you have a picture uploaded on this forum?

[Poultrygeist]

I have more than ones done measurements with REW of some monitors and thinking it sounds pretty nice and didn't realize until I saw the frequency plots that I had forgotten to turn off the bucket subs. Once the buckets were turned-off, the sound was thin and it definitely feel like something is missing. You can't really call the bucket subs a HT subwoofer monster aimed at movies, but for music, they are great!

Yes, they are ugly, but they are so small it easy to hide them, or you can do like Poultrygeist and spend a little bit extra time and make them in pianoblack and chrome. PG - do you have a picture uploaded on this forum?

If I can find a picture I'll post it. I've got mine hidden behind furniture and since they're up firing, space is less of an issue.

[Poultrygeist]

Bucket subs ( piano black special ordered from Home Depot ) and Yung SD300 plate amp.

[Odal3]

  Probably the nicest bucket subs out there!!!

[Poultrygeist]

Nobsound preamp with Y cables feeding bucket sub's plate amp and dual chip TPA3116 class D amp ( lower right ).

[Odal3]

A Crown XLS-1500 amp (currently marked way down due to XLS-1502 coming to market) with (2) of the Peerless 8" speakers with buckets & all the necessary hardware is in the $500 range. Adding another bucket sub & 3 channel amp would drive the price up further ...

For $500 you can probably get 4 bucket subs and an amp if you look around. PE has the Peerless drivers on sale for $66 and you would need to add bucket, concrete, etc. for maybe $10 more, and there are some places selling the crown xls 1500 for ~$200, and you may be able to find one even cheaper used. But, my guess since you are only trying to get rid of a dip in the range your main speakers are alredy playing, you probably only need 2. I use two Y rca splits from the preamp. Another option is speaker level in to the crown (needs a special cable with speaker input on one side and rca on the other with some resistors in between) or plate amp. BTW: Note that you need a hot signal to take full advantage of the crown.

(3) used garden variety powered subwoofers off local Craigslist can be had for $100 each or so. This would be to experiment with, not be the end all be all final solution. I can sell the used subs on Craigslist & recover bulk of the money if I choose to go with better quality subs or take a different route.

I tried the same option, but at least the cheap $100 subs I could find on craigslist left me dissapointed since they didn't blend well - more like the one note rumble. For $500 you can get one decent sub with included plate amp that may fit the bill. If you only want to experiment, perhaps the best option is to buy something with good return polices.

I'm also really curious about the audiokinesis swarm system. Hope to hear it one day. Best of luck and have fun experimenting!

[andy_c]

FWIW I find all the adjustments with the Geddes method too much to bear, I find one sub in the middle of the front wall gives good results, one on front middle and one on back middle better, and after that it's hard to see a dramatic improvement without going to nearfield dipole subs. (YMMV, JMHO, etc..)

I've written a freeware called Multi-Sub Optimizer to help with this problem.  There's a thread about it here. It requires that the measurements be taken with a setup that preserves the delay difference from one speaker/sub to the next.  One must use an XLR mic or similar with loopback timing reference in REW, or an equivalent approach such as time locking with HolmImpulse.

It calculates individual EQ, delay and gain of the DSP channels driving the subs to get the flattest combined response of subs and mains at multiple listening positions.

[brother love]

Poultrygeist,

Thanks for the info/ photos of your preamp &  Y cable connections to your plate amp & class D amp. Love the black buckets.   

I searched Google & Amazon & couldn't find output voltage & impedance for the Nobsound NS-01P preamp. The Grant Fidelity TubeDAC-11 has pre line output/ tube buffer output: max 6V & output Impedance: Line out and Tube out - <20 ohm.

Odal3,

Thanks for sharing your personal experiences with garden variety subs & bucket subs.  I used to own a GR Research 12" servo sub as part of my system. It was fast, clean & very musical, but room measurements resulted in more problems than running full range mains only.  I want to try the Geddes 3 sub method to see if I can achieve a flatter frequency response below 100 Hz than I currently measure. I may end up like JohnR & not be able to tweak the 3 subs enough to get there, but I want to try. 

So if I go "cheap & cheerful" with 3  used subs, & how to most economically connect with my existing system:

I could use the Y cable from the tube out of the TD-11 to feed the TBI Millenia MG3 for the full range mains, & to feed the plate amp of the 1st sub.  I could daisy chain RCA cable from out of 1st sub in to 2nd sub plate amp,  then out of 2nd sub in to 3rd sub plate amp.  I assume that the 2nd & 3rd subs are slaves & lose control capabilities (crossover, phase, etc.).  Not sure about the volume control for 2nd & 3rd subs.

If controls are not lost for 2 downstream subs, then I would likely go this route just to see what net effects I could measure for my room/ acoustic treatments/ audio sound system that could be achieved on the cheap ($200- $300 range).  If results are good then I keep set-up "as-is". If not, I sell 3 plate amp subs for close to what I paid, then go Crown amp/ bucket subs route ($500 for 2 subs, & $600 for 3 subs if determined to be needed after measurements of 2 bucket subs).