Help with music only subs {very long} (1 Viewer)

[Andrew McMillan]

Greetings-

This seems to be the place to gather information on DIY subwoofers, and since I am planning my first project I turn to you guys for some advice. My system is for music only. Current system consists of ACI Jaguar speakers,(factory built) McIntosh MC-202 amp, McIntosh C-15 pre amp, Myryad CD player, assorted other stuff. The Jaguars are great, but I always intended to use them with a pair of subs. I have outlined, as best I can, what I am looking for in my project. Here it is;

1) Fq response that is more or less flat from 20-80 hz in room. I will be using a Marchand XM-9 crossover (24 db/oct) between the mains and the subs. I would like to try and use 80hz, but if that is too high, I could drop as low as 60. I want to try and free up the midrange a bit on the Jaguars, and relieve some congestion that I hear in the lower mids. I do not want to use any eq.

2) Relatively modest SPL. I am absolutely stunned by some of the numbers you guys are getting from your DIY subs. I can’t even imagine what 120 db @ 15hz must be like. My listening rarely exceeds 90db, and is usually confined to 75-85db. So, for adequate headroom etc. I would like my subs to play cleanly to around 105db @ 20 hz. (in room) I won’t use any performance beyond that, and am unlikely to even go for 105. But, I do want it to be clean, and very very low distortion from 70-95 db, again 20-80 hz.

3) Size: I want to keep the enclosures down to around 100 lbs each, probably in Baltic birch ply. I figure that to be about the max. that I can move on my own with a dolly and not strain the back. Given that weight restraint I would set 8-10ft^3 gross box volume as my limit.

4) Wood box; I don’t think tubes are for me.

5) Front firing. I want to see my drivers!

6) Budget: No more than $300 in drivers for each sub.

7) Power: I want to use a standard audio stereo amp, something like 250w into 4 ohms. No fans, no pro amps. I have a good Rotel that I can use for now, eventually to be replaced with an older Bryston or similar.

8) Room: I am moving in 4 months, so I don't know what room these will be going in, but it will probably be a normal sized "average" living room. Say 10 by 20? Certainly not a huge room, but not too cramped either....

Ok, so with those goals in mind I have read and read as many posts as I can find here. There is a tremendous amount of information in the archives. I think a sealed enclosure with a low Q is what I want, since this is a music only system. I have modeled several designs, as best I know how, in WinISD, and the sealed boxes always seem to be 7-8 db down @ 20 hz. Given careful room placement can I hope for flat response? I know that this is totally room dependant, but in your general experience what kind of gain should I expect, in room, from 20-30hz? I still have many questions. Most importantly I guess, is what size driver, and which one to buy. Re size, 10, 12, 15 or 18? For that tight natural music bass sound I am looking for, what size should I be considering? Can musical bass be had out of an 18” driver? Would say twin 12s or 10s be better than one 18? (twin 12s or 10s in each sub, or 4 total for the system) I can’t remember seeing a main full-range speaker that relied on an 18” woofer, in fact the biggest woofer I can think of that I have seen built into a speaker would be the 15” used in the B&W 801s. Should that be telling me something? Drivers that seem to stand out as being good candidates are: ACI, NHT, Aidre Tempest and Maelstrom, and some of the drivers from Stryke. Ok, this is way way to long already. Any advice that can steer me in the right direction would be very much appreciated!

 

[jeff lam]

You sure you want to DIY? Maybe a dual Titan II LE set up would fit your needs. I can only imagine what those Jags sound like.

Since you specified music, I would think the Titan II LE's would be perfect.

If you want to DIY, I would probably suggest a sealed Tempest (Low Q) design much like what Rudy H has (except his is a Dayton DVC from partsexpress).

Good luck!

 

[Brandon B]

I would consider the Lambda SB12's from Stryke Audio. I am using the SB10's for a similar purpose, and they are great.

BB

 

[Cam S]

If you have the coin, and you don't already have them, why don't you conisder matching your Jaguars with the LFM dual 10" sub bass module that matches the Jaguars in every way. I would go that way if money wasn't much of a concern.

 

[Cam S]

sorry, just remembered you had a budget of about $300 for the drivers. Well I would go with something similiar to Eric Jones' Shiva sub stands that he built,
http://www.jones4.com/ss. Make them dual Shiva's for each stand kinda like the ACI LFM's. that would be nice, and pretty dam cheap.

 

[Peter Johnson]

What about something such like the new Adire Brahma's, linkwitz transformed to trade a little SPL for extension.

 

[Dustin B]

I'd email Dan. A pair of low Q sealed Tempests or Maelstroms with a good two channel amp, proper placement and calibration would produce some excellent bass.

I don't think the Brahma would work that well as their impedance is just too low for the kind of amps that are going to be considered for this project. Given the goal, and the budget, I believe the Tempest or Maelstrom would be a better option.

 

[Brian Bunge]

I built a 1.5ft^3 sealed enclosure for an SV10 (same driver as the ACI LFM's and new Force subwoofer) for a friend of mine and she loves it. It's going into her bedroom system. The Qtc is around .6 IIRC. I don't know how flat they extend in room though.

Brian

 

[Pete Mazz]

I'll put my vote in for a low Q sealed Tempest, also. It may not go ruler flat to 20, but damn close with room gain. For music I think you couldn't go wrong.

Pete

 

[MikeAcc]

I would stay in the family and go with the ACI SV10 or SV12. Same drivers used in the Titan and Force subs that are pre assembled from ACI.

Should integrate very nicely and be outstanding musically.

 

[Andrew McMillan]

Wow! Thanks for all the replies. What Cam has suggested sounds really interesting. What would you think about using two Shivas on each side? (4 total) Is it better to reach your SPL/Fq goals by having more drivers and keeping the power low or to use a bigger driver and push it harder? My past experience has been that drivers tend to perform, at least subjectively, better when they are not straining or at their limits. I am new to subs though, so maybe that doesn't apply here as much? If I wanted to stay in the family, as Mike suggests, I could use two SV-12s in each box. I've modeled some dual driver sealed boxes in WinISD, but the Fq. response always seems to roll off faster, even if I double the enclosure size, with two drivers. Why is that? It seems like I couldn't go wrong with a pair of sealed Tempests or Maelstroms, what would be your preferences between those two for music? I got to admit the idea of a twin dual driver boxes intrigues me!

 

[Ryan T]

I have a sealed tempest (Q .577) and its awesome for music! I also wanted a front firing box so I altered the adire designs. you can see a pic here...
http://www.geocities.com/ryandtodd/sealedtempest.html
Here is my spl "chart"
Hz--------db
12--------70
16--------74
20--------79
24--------69
28--------77
32--------81
36--------82
40--------83
44--------81
48--------85
50--------86
54--------83
58--------74
62--------73
66--------75
70--------82
72--------83
76--------83
80--------84
84--------83
88--------82
90--------81
94--------81
96--------80
100-------76
My response is not to bad in my opinion. I was fiddling around with lspcad today, I found my tempest in room can hit 3.43 Hz! To bad I can't hear that low . My room is really small (10' by 14') so I'm not sure what kind of boost you will get. I hope this helps.
Ryan

 

[ThomasW]

Andrew

There will be no sonic benefit from 'staying in the family'. If you want to give ACI your business fine, but their drivers offer no inherent advantage in this situation.

80Hz XO point should be fine, might pick up a couple of extra modules if you want to experiment. The damping controls on the XM9 will allow you to trailor the blend between the subs and the mains.

Tempests are excellent drivers and a bargain compared to dual Shivas.

If you aren't a hardcore SPL freak; then using Tempests as opposed to Brahma, Maelstoms, or any other high excursion driver is a good idea

Grab a copy of the freeware Adire LspCAD. It comes preloaded with the Adire woofers parameters, and is more accurate than WinISD.

BTW, there is no inherent sonic advantage to using smaller drivers. The concept that smaller drivers are faster is a myth

 

[Robert_Gaither]

All the driver suggestions given are great choices and I seriously doubt that any would fail with such a degree that it would disappoint you (you'll get at least a smooth mid 20s no problem especially since you stated that you are willing to go 8-10 cu ft cabinets). If it were me I would lean the way of either aquiring some of the older SVS woofers and modeling a sub with them (don't count off ported, an EBS alignment are quite natural sounding) or buying a Blueprint BPD 1001/1201 and an eq (I know, I know you stated no eq). Too bad this isn't your permanent resident or I would ask you to join the "Cult of the Infinely Baffled" and box size wouldn't be an issue.

There are two problems that I see that might affect your design and performance goals. First the less than 100 lb cabinet (lifting sheets of mdf and the required bracing for a large sealed cabinet, even with BB, this might be hard goal due to the requirement of the braces, double front and rear baffles, and etc; though mdf should still be considered from a good sound damping building material perspective) based on some of the Diy project for a large cabinet since most of us would brace the hell out of it plus damping materials, stuffing, and driver itself (Brian Bunge has a nice pic of a small ACI SV10 driver in a pretty small cabinet weighing almost 50 lbs!). The second is that you don't want to eq to help "force" a flat response (just eq between the marchand to the sub amp, and thus keep the the Jags happy to sing clean) would mean either your room is built great, heavily treated, and of course having the sub placed perfectly. I know eqs have a bad rep but too truly reach a flat performance for most subs this is almost alway required to remove a bad room mode that most likely will happen.

 

[Richard Greene]

Musical bass in most home listening rooms requires a room full of bass traps, or a few bass traps and a parametric equalizer, or at least a parametric equalizer.

No driver or enclosure at any cost can defeat room bass resonances. No matter where you sit you will have at least one loud bass boom at a specific frequency (sometimes at two or three frequencies) and one trough. The distribution of bass energy in home listening rooms is very uneven.

You can't do anything about the troughs using an aqualizer but you can reduce the SPL of any peaks heard at your listening position. This will cause a large improvement of bass quality.

I use a DIY low QTC (230 liters stuffed with 8 lbs. polyfill) sealed single 15" (Adire Audio Tempest) driver

subwoofer. Bass roll-off is noticeable below 30Hz. with this enclosure design. If you want high output at 20Hz. you'll want a ported enclosure or you can equalize a sealed enclosure (a strain on the driver and amplifier unless you listen at moderate SPL's.) I tried equalizing my Tempest driver flat to 20Hz. but my walls resonate at 18-20Hz. so that caused more problems than it solved. Don't count on a lot of room gain unless your room is small and well sealed.

 

[Andrew McMillan]

I think my original goals were too optimistic. Flat to 20hz seems out of reach without going either ported or with an eq, both of which I want to avoid (Robert, your idea of putting the eq in just for the subs is a really good idea, and one I hadn't thought of, I will investigate this more).
So, I guess what I am looking at now is just getting the smoothest response possible to the middle 20s. There isn't much music down here anyway, and it seems a fair trade off. I am going to download the software from Aidre, and play with that. The Tempest and dual SV-12s seem like the frontrunners at this point. I am sure i will have additional questions in the future. I'd just like to say that I have posted on many message boards in the past (audio and others), but I have never gotten such detailed and helpful responses as I have here. Thank you very much for sharing your experiences with me.