12" Driver and Amp Recommendations for noob

**hjmiller** · **04-07-08, 12:43 PM**

I am working on finishing my 7.1 setup that already includes an Onkyo 605, Polk R150's, in all front/surround positions, and the CSR center. I plan on upgrading to Polk Monitor or RTi towers eventually in the front but for now this was a very affordable way to get something better than just buying the Onkyo HTIB.

So I still need to add a sub and of course based upon my speaker selection you can see I am on a failry tight bugdet relatively speaking. I had originally planned to get the BIC H-100 based upon how well received it is online, but couldn't help but wonder if I should save up my $$$ for a HSU STF-2 or VTF-3 or SVS PB-10 so I wouldn't ever worry about upgrading. Then I considered a DIY sub as a god compromise between the cost of the H-100 and the performance of the HSU or SVS, but want some feedback on choices and expectations I should have.

Here are my design criteria I would look for if I proceed:
Cost - $200 to $300 total.
Amp - Buy a plate amp. PE 240W or BASH 300W? Others to consider?
Driver - Thinking 12" but obviously I would consider any recommendation that meets my overall criteria.
Performance - Would like something to reach ~18-20Hz in room. I am not going to listen to it that loud to be perfectly honest as my wife and two little girls will complain and I never get to watch a movie completely by myself, but it is nice to have something with some oomph if needed. Most use is HT, but do listen to a fair amount of music on the system as well.
Size - Want to try and squeeze it in a corner behind a large chair out of sight. The corner probably creates a 3' X 3' tiangle or so. There is a heat register I will have to deal with if the sub encroaches on it. Would want the sub to stay below the back of the chair which is probably 36" or so high.
Room - 17 X 19 X 10' ceiling, open 60% on one end to kitchen and hall.

I have a large set of good tools and a decent background in woodworking and home remodeling so construction of the sub from a cabinet standpoint is not an issue.

Detailed questions:
Driver - Recommendations? I kind of think the driver would be $100-$150 of the budget, but not sure how to split the cost between the driver and amp so that one is balanced with the other (1000W amp hooked up to puny driver not good, and monster driver hooked up to underpowered amp is a waste as well). I originally was looking at the Dayton Reference driver , or Dayton Titanic, but there are probably many others to consider. 12" a good compromise for the performance and size restrictions I have?

Amp - As mentioned been looking at the PE Dayton 240W or the 300W BASH. If they cost the same I would go with the BASH amp most likely. 300W vs. 240W plus based upon the lack of a major heatsink it is apparent it is a much more efficient design (less likely to kick the breaker and less $$$ in electricty), however not sure the extra $50 is worth it at my budget. If I go with the Dayton should I get the bass boost version or standard? Other brands in a similar price range to consider?

Design - Any recommendation on a starting point for a plan for a ported box design that I can tweak once the driver is picked out? The fit would be easiest if I made the box taller, and miminized the width. Are there restrictions on aspect ratio to be concerned with other than just bracing?

Thanks,
HJ

**BoomieMCT** · **04-07-08, 01:34 PM**

Welcome to the world of DIY! Now for some expectation managment. DIY is great if you enjoy building stuff and does give you more performance for your dollar (or euro or whatever) but the cost benefit gets bigger the more you spend (more benefit with a $600 budget vs. $300). At your price point I believe you can make a great sub but the difference between it and a comparably priced commercial sub won't be as extreme as other price points.

Quote:

hjmiller wrote:

Detailed questions:
Driver - Recommendations? I kind of think the driver would be $100-$150 of the budget, but not sure how to split the cost between the driver and amp so that one is balanced with the other (1000W amp hooked up to puny driver not good, and monster driver hooked up to underpowered amp is a waste as well). I originally was looking at the Dayton Reference driver , or Dayton Titanic, but there are probably many others to consider. 12" a good compromise for the performance and size restrictions I have?

12" is a good size but I wouldn't get too hung up on the driver size and instead would concentrate on what the driver can do. I suggest getting a modelling program like WinISD or Unibox (both free) and make some test models using different drivers. Advice is great but it is always good to be able to fact check stuff yourself.

That being said since your room is so open you probably won't get a lot of room gain so I'd suggest a traditional ported sub. The Dayton Titanic drivers are good (I use them myself) but they don't have as much difference between their xmax and xmech as some other options so they aren't forgiving if you drive them too hard below tuning in a ported box. I'd take a look at the Torrent Minstral, Exodus Shiva-X
and Tempest-X.

Quote:

hjmiller wrote:

Amp - As mentioned been looking at the PE Dayton 240W or the 300W BASH. If they cost the same I would go with the BASH amp most likely. 300W vs. 240W plus based upon the lack of a major heatsink it is apparent it is a much more efficient design (less likely to kick the breaker and less $$$ in electricty), however not sure the extra $50 is worth it at my budget. If I go with the Dayton should I get the bass boost version or standard? Other brands in a similar price range to consider?

Both are fine. I use the PE 500W BASH amps in my HT but the other Dayton amps have a pretty good rep. In your price range the only other thing I've heard of is a 300W MCM amp that was on sale (and might still me). The bass boost PE amp is more for sealed designs and usually isn't necessary on ported ones.

Quote:

hjmiller wrote:

Design - Any recommendation on a starting point for a plan for a ported box design that I can tweak once the driver is picked out? The fit would be easiest if I made the box taller, and miminized the width. Are there restrictions on aspect ratio to be concerned with other than just bracing?

Decide on a driver *before* you cut anything! Look at your space and figure out what the biggest volume sub you can build is. Don't forget to take the thickness of your material, port volume and bracing into account. Now you have an upper bound for modelling drivers to see which would work best. Having subs with big volumes is where DIY really starts to seperate itself from commercial subs (which usually have strict volume limits for marketing purposes).

**mayhem13** · **04-07-08, 09:27 PM**

Well said boomie, I think at $300 budget,the price vs performance issue goes to ready made. Shop on line for some great deals-watch for specials and i'm sure $300 will get you a decent sub. After reading this and other posts you'll probobly find more $$$ in your budget and if you can squeek $550-$600 in there and you have 5 square feet to play with then you will best all commercial offerings in that range-good luck and hope you don't get bitten by this DIY virus like the rest of us-there is no known cure!

**BoomieMCT** · **04-07-08, 09:40 PM**

Quote:

mayhem13 wrote:

Well said boomie, I think at $300 budget,the price vs performance issue goes to ready made.

Well, that's not quite what I said and I'm not sure if I'm ready to concede that point. Certainly to do better you need to shop around a bit. DIY'ers also always have an advantage if they can make large enclosures which (most) commercial companies aren't wont to do.

**mayhem13** · **04-07-08, 11:05 PM**

You still have to consider time and materials to some degree-and FINISH-i don't think anyone really wants to look at an ugly box. For $300 what are you gonna get ? You can buy an infinity ps12 sub with 12 driver and i think 500 watts peak reserve already engineered and quite attractive with a warranty for $225. So you buy a Pe amp with shipping $120-now you buy a sub lets say $120. Now you gotta buy box materials,finish materials,stuffing,yadayadayada. At that budget as much as it may pain you to concede, well you get my point. UNLESS you have passion about creating something. Thats when the value becomes imeasurable. But just from a performance point ?? Did you read that thread on the subject on AVS ? Very nasty stuff that spun waaay outta control !

**hjmiller** · **04-07-08, 11:22 PM**

For the $300 I listed as a rough budget the best I can do off the street is a BIC Acoustech H-100 or Cadence sub-12 (12" drivers and 25Hz extension), or a 8" HSU STF-1. Step up to $380 shipped I could get a STF-2 (10" driver and 25 Hz extension). Spend $480 shipped and I could get a SVS PB-10 NSD (10" driver and 18 Hz extension). $550 would net a HSU VTF-2 MK3.

I'd like to think I could build something that would complete or beat all of these options within my target range but do understand that as you go cheaper the loss of quantity discount and factory building of cabinets diminishes my returns. There is also just the pride of having built something for yourself. I'm sure it drives most of you to keep building new subs more than any need to continue pushing the performance.

That said I would like to go through the design process just to see what could be possible. I looked at the Torrent driver recommended but am slightly gun shy on that one as there seems to be some debate as to whether they have published all the specs for it or if one should use the old db500 parameters to properly model it. It is a great deal at the price, but they don't list Xmax or Xmech. I know some of the threads expressed concern regarding the use of 4 Ohm DVC in that driver which means I couldn't wire it up to a single sub amp output at 4 Ohms as a single driver. The Shiva-X looks great but is quite a step up in cost. Any other worthy drivers to consider?

Another question.

Do you need to isolate the AMP (a separate chamber for it) on the inside of the enclose from the main chamber to prevent damage from vibrations or air leaking through the amp?

**Mike P.** · **04-07-08, 11:37 PM**

For a $300 budget I'd suggest a Mistral 12" DVC subwoofer:
http://www.torrentaudio.com/mistral12dvc-p-73.html

A Dayton 240 watt amp:
http://www.partsexpress.com/pe/showd...number=300-804

Built into a corner sub something like this:
http://www.hometheatershack.com/foru...-feedback.html

This would meet most of the needs you stated, and would out perform any commercial sub for $300. And it would be fun to build.

**hjmiller** · **04-08-08, 07:04 AM**

That is exactly the type of project I had in mind. I have two corners I could consider for placement. One is behind my projection TV, and the other is behind a chair on an angle in the corner. My first instinct is to go behind the chair as it will be more nearfield to most of the seating in the room, and I am concerned about the pastic enclosure on the TV resonating with the sub behind it (I had it happen with even a cheap 6" passive sub on an old HTIV system I had). Also worried about whether I would need shielding for the rear projection.

I think the Minstral and Dayton amp are definietly a budget choice combo but still wonder if anyone has any more information on hooking up the DVC on the Minstral (it is dual 4 Ohm correct?) and whether that is going to severely limit my output by limiting the AMP to much less than rated power (though I probably could live with the 1XX watts I got out of it just fine).

Also the project shown used an upfiring construction. I assume that the same limitations apply as for a down firing approach in terms of less than 5% sag as a limit. I'd rather build it down firing to prevent dust and kid based garabage accumulation on the driver and in the ports. Has anyone confirmed the Minstral can be configured down firing?

Thanks for all the advice and help.

**Warmon** · **04-08-08, 11:42 AM**

Mike's suggestion is good. I have another that might work. I have two new Tang Band W8-740C 8" Subwoofers up for sale in the classified section. You can mate these up to the same PE amp - or if your handy with electrical and can run yourself a dedicated 220v circuit - get two Cerwin Vega amps at ApexJr for 55 bucks each...each sub getting its own dedicated amp in a single box...either way, slightly less or just over $200. I haven't modeled the Minstral, but I believe the two W8-740C's would give it a serious run for the money.

**Mike P.** · **04-08-08, 12:20 PM**

The Mistral is a DVC clone of the SVC DB-500, down firing shouldn't be an issue. There is a math equation to check and make sure, but I can't find it right now. Hopefully someone will chime in on this. As for powering the DVC you could always upgrade the Dayton amp in the future should you decide it's needed.

**hddummy** · **04-08-08, 02:41 PM**

The Minstral and the dB500 model almost identical regardless of which set of parameters you use. I'd say the minstral T/S numbers are good since using DVC does change things slightly. Both drivers work well in an vertical mount configuration. %SAG=24849/(Xmax*Fs^2) If it is the same as the db-500, Xmax is 20mm. I don't have Xmech, but I've never bottomed mine out. That puts your percent SAG at ~2%.

I've never experienced any magnetic shielding problems or issues with the screen shaking. I suppose that will depend on your exact set. I built another "behind the TV corner sub" for a buddy and his RPTV has no issues either. You might be a little more concerned if you have a CRT projection screen, but I don't remember if you said what type you have. I used a Fi driver in his and it turned out fabulous as well. check it out.

http://www.hometheatershack.com/foru...-im-again.html

Finally, your amp....Do you have room for a pro-amp. You can buy a Behringer A500 that will give you 240W into two 4 ohm channels for 200$. I think that would be a perfect match to the DVC Minstral. In fact, If I had known about the Minstral driver, I probably would have done that instead of a db-500 and a buttkicker amp. If you need to spend a little less, a Pyramid PA600X for $150 will give you 150W into two 4ohm channels. Otherwise, I wouldn't try to connect a DVC in parallel to a 4ohm plate amp and series would limit the power output.

**hjmiller** · **04-08-08, 10:31 PM**

Wow another good suggestion. Any major differences between the ED and the Torrent that would steer one in one direction or the other? Looks like the ED design is a bit heavier duty construction and the W RMS is higher, but the Torrent had a higher Xmax I believe by a bit. Any differences in the parameters that would affect flatness, extension, box size, or other design factors that I should consider.

Also saw a used SVS 12.1 driver on a forum classified site for $50 I think. It looks like a db-500 if I am not mistaken. I assume it would be 4 Ohm SVC construction. How would that rate against the above two choices?

Also have to still consider earlier feedback about buying commercial at my price point. $375 for the ED A2-300 which would meet all my criteria except for the design flexibility to fit snug in a corner.

**hjmiller** · **04-09-08, 07:43 AM**

Well I bit the bullet and ordered the ED 13Ov.2 D4 driver they have on clearance right now so I guess I am committed to taking the plunge. Now for the fun part, modeling. Lunch breaks at work will be busy over the next few weeks.

Plate amps at PE are on backorder so I will have to wait a bit on that but no real rush at this point.

**hddummy** · **04-09-08, 10:13 AM**

If you want to use a plate amp, why the D4 and not the D2. you will have the same problem with connecting to a plate amp as you would have with the torrent. A D2 can be connected in series for 4ohms into a plate amp. The D4 will be either 2ohm parallel or 8ohm series.

**hjmiller** · **04-09-08, 12:06 PM**

The ED D4 is $70 clearance right now, the D2 version of same driver is $175. Another recommended option was the Torrent Minstral also a D4. I know its not ideal but to tell the truth power will probably not be an issue as I will rarely need to peel the paint off the walls.

**BoomieMCT** · **04-09-08, 12:14 PM**

Quote:

hjmiller wrote:

The ED D4 is $70 clearance right now, the D2 version of same driver is $175. Another recommended option was the Torrent Minstral also a D4. I know its not ideal but to tell the truth power will probably not be an issue as I will rarely need to peel the paint off the walls.

Headroom is a wonderful thing. I think two of those ED D4's would be great in 1-2 cubic feet sealed (or some equally small ported enclosure).

Good point though. You could always hook up only one VC (after adjusting the T-S parameters in your models accordingly) which should provide less of a hit to your potential power. You could play around with adjusting Q by adding resistance to the other VC. Adire audio had a good article on this - I'm sure it still exists somewhere in the ether.

**hjmiller** · **04-09-08, 12:50 PM**

Need some help here on the ED driver and an enclosure. I posted a queston last night regarding how they would perform design wise versus the Torrent, but then was worried they would clear out fast and ordered one this morning without modeling or getting an answer. I am modeling the ED design in winISD with a ported design and am having trouble getting a decently flat response down to 18 or 20 Hz without going monstrous. As a sanity check I threw in the Torrent parameters and was amazed at how much flatter the response was and the box could be less than half teh size to reach the same extension. Does this make sense? Is the ED not ideal for a ported design with low extension? I took a leap of faith based upon it basically being the driver in the A2-300, but maybe they do a ton of custom EQ to get that more than just box design.

Here are the parametes for the ED:
Qts: .28
Qes: .30
Qms: 3.3
Fs: 21 Hz
Re: 8.3
Vas: 176 L
Mms: 195 g
Bl: 21.7 T*m
SPL: 89.1 dB
Sd: 545 cm^2
Xmax: 18.3 mm
Voice Coil: 62.5 mm

and the Torrent:
Qts 0.453 Rp 5.93Ω
Qes 0.534 Dia 241mm
Qms 3.347 Vas 71.0l
Fs 24.7Hz mms 169g
Res 7.55Ω cms 246um/M
Ls 6.26 bl 19.2Tm
Lp 6.55 Spl 86dB

Does this all make sense? Should I try and cancel the ED and go with the Torrent? Please help!!!!

**Mike P.** · **04-09-08, 02:49 PM**

Quote:

a decently flat response down to 18 or 20 Hz without going monstrous

What size cabinet did you model? For comparisons sake, model both drivers in 4 cubic feet tuned to 18hz and input 200 watts. Now compare them in the SPL graph. Thet are within one db of each other at 18hz and they both reach maximum excursion around 14.5hz. The Ed sub will do fine.

**hjmiller** · **04-09-08, 03:05 PM**

You are right about the 1 dB difference. I guess I was concerned about response flatness. From 80 to 18 the ED drops 7 dB. The Torrent only drops about half that though much of that is an increase in gain at higher frequency. Will the EQ in my Onkyo help flatten out the rest of the response?

**hddummy** · **04-09-08, 03:28 PM**

The Minstral has a flatter response which is desirable. The ED is much more efficient, so the low end will have the same SPL for a given power input from the amp. If you want a flatter response out of the ED, you'll have to tune a little higher. With an 80Hz crossover and the 63Hz EQ on your onkyo pulling the band down another 3dB, the ED response should be reletively flat with the 18Hz tune.

Do not connect only one channel of the DVC. The T/S parameters will get wonked up because you have an inactive coil and an active coil next to each other. You'd be better off putting them in series and running 8ohms. I'd rather use the full motor and half the power than half the moter at the amps rated power. You'd have lower THD that way too.

**Mike P.** · **04-09-08, 03:34 PM**

What the graphs don't show is the effect of the room that will alter the response. (room gain) After the sub is installed, the use of REW will show the "final" response of the sub and will tell what equalizing is necessary at what frequency to achieve a flat as possible response in your room.

**hjmiller** · **04-09-08, 05:28 PM**

Thanks for all the feedback. Part if the original problem was I was looking at he gain chart versus SPL. Gain for the ED drops off much quicker than the SPL which I assume is attributed to the difference in efficiency.

Does anyone know if the Audessey function in the Onkyo provides feedback on the actual SPL at certain frequency measurements?

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