DIY subwoofer questions/thread

thejck

So I want to build 2 subwoofers for my living room. They will be used besides the couch and do double duty as end tables to please the wife.
Room dimensions
16 by 20 (10 foot ceilings)..open to kitchen along 16 foot length kitchen area is 30 feet long. there are then door size openings (no door) to the dining room and foyer.. foyer is height of 2 stories.

Here are some of the options I have been throwing around.
1. Single TC sounds 15 inch driver in each box
2. Dual Dayton 15 (not sure if I should do the titanic or the reference)
3. Friend says do dual 12 daytons (easier to control) (however the 15 is only 20 dollars more than the 12)
4. 15 inch driver from exodus (would be a single driver per sub because of the cost)
5. Single 15 inch exodus driver from diycable
I want to set them up besides the couch. Almost like end tables to please the wife. If I did a dual driver set up and one of the drivers faced the side of the couch would that be an issue?
Not sure which Dayton driver to choose. The Titanic or the reference. My friend likes the metal cone of the reference but everyone talks about the titanic.

haven't decided on a plate amp vs a pro amp to power them. I will have to run speaker cable to the back off the room as all my other equipment is on the front of the room.

Face

Here's an option for amplification: http://www.parts-express.com/pe/showdetl.cfm?Partnumber=300-811

I like how it's rack mountable like a pro audio amp, but has many more features to help tune in the sub(s).

thejck

I know that amp says 950 watts at 4 ohms but it has output for 2 speaker terminals. Is that 950 per terminal or does it consider if one load in either parallel or series?

quadzilla

It's a mono amp, so 950 total.

JimAckley

I've good things about Rhythmik Audio's DIY kits. When the funds line back up, I'm going to order a kit from them for my 2-ch system.

thejck

Has anyone worked with passive in a subwoofer. I want to keep the box smaller for WAF. I was reading about the advantages of using passives to compensate for the lack of space for a port

Face

These have caught my eye.

http://madisound.com/store/product_info.php?manufacturers_id=183&products_id=8535

https://www.madisound.com/store/product_info.php?manufacturers_id=183&products_id=8867

thejck

I was looking at these kits.
http://www.aespeakers.com/phpbb2/viewtopic.php?f=3&t=2441
I am going to see about doing the cabinet myself. Either the single 12 or single 10 with dual passives.
I know they are having some production issues with the AV drivers. Anyone listen to any Acoustic Elegance products before?

Do you have to maintain a size ratio between the passive and active drivers? I know they recommend balancing the passives to prevent vibration

Face

I would call to make sure he has them in stock before ordering. If not, I'd look elsewhere unless you have a lot of patience.

thejck

I am not in hurry to do this. I am going to wait and see what it going on before I order them. I have heard lots of good things about his drivers.

Would i be better off doing a 12 inch and 2 15 inch passives or a 10 inch with 2 12 inch passives for my room?

Another thought is to use the design idea with other drivers if they are not making the AV series anymore.. if I can figure out how to use WINISD or something.

Face

I would call and ask for his recommendations.

Generally a 15 passive would be fine with a single 12 driver, etc...

Some recommend a passive with twice the surface area as the active driver, some say the same size will be fine as long as the passive has twice as much travel(x-max) than the active driver, it all depends on who you ask TBH. But you examples above sound like overkill.

JimAckley

Take a visit to www.hometheatershack.com and get on their forums. They have a section dedicated to DIY subwoofers, and a few threads dedicated to the use of WinISD Pro, as well as additional driver files.

ben62670

Music or HT? If you are looking at music I would go sealed. I have two 15" Titanic's that are amazing sealed. When I used them in a sonosub they would dig much deeper.

thejck

I am planning on doing 2 subwoofers on either side of the couch along the back wall.
They will mostly be used for movies as I am not planning on having them hooked up to the system I use my SDA's with. However I got access to some DVD audio and SACD content with 6 channels that I might use my other polks for that would use the sub.

How tall are the sonotubes? I dont want this to be 2 tall as I want them to work as end tables as well.

Face

thejck wrote: »

How tall are the sonotubes? I dont want this to be 2 tall as I want them to work as end tables as well.

It depends on the driver you use and the diameter of the enclosure you choose.

Unless you go wide, they may not work as end tables as the port is generally on the top.

greyford1979

Just an idea and very huge on the WAF scale if you wanna please the wife. Built this for a friend and his girlfriend loves it. They are wanting a second built this summer to match. Goes low and sounds great without even a rattle on top where they have their lamp and pictures. Another cool factor is that they said when they have people over everybody is completely surprised when they feel and hear the bass and don't know where it's coming from lol Let your imagination run wild and good luck!!! Looking forward to seeing what you end up building.!!!

http://www.polkaudio.com/forums/showthread.php?t=110243

thejck

Thanks for the link. what are the dimensions of it. I was looking at this build thread just now so we are on the same track
http://www.hometheatershack.com/forums/ported-subwoofer-build-projects/23557-slot-port-tempest-x2-end-table.html

greyford1979

Yep similar to mine lol. Without having the plans I made right in front of me, the top was right around 27 in x 24 in. The width of the driver enclosure with the legs was around 22 in and I think 25 in long and maybe 21 in tall. The legs were 24 in tall making the entire table right at 25 in tall. The actual enclosure volume if I remember right was 4 cubic feet. I actually went off of some of the dimensions of the end tables they were using, the one I built was just taller and had a sub enclosure ofc lol.

jcandy

There are endless variations for building a sub. Many of them are in the fantasy-only category because of WAF limitations. The Dayton Reference HF subs are a very safe bet

10"=RSS265
12"=RSS315
15"=RSS390

and for most people the only remaining questions are (1) what model and (2) ported or vented. These drivers all have low Vas, so they will have very good extension in reasonably small boxes, but will in trade require lots of power. I find that people are usually somewhat naive in their approach to building a sub and nearly always insist on porting to obtain the lowest possible f3. With a sub, taking into account the room modes and room gain is important unless you are prepared for an unmusical noisemaker. By going sealed with the RSS drivers, you will have a much easier time building the sub (no ports or passives), the size will be minimized (no 6 ft^3 monstrosities), and the in-room response will often be be flatter.

Also, if you want to minimize room modes (i.e., if you want to avoid huge +/- 10db shifts in the SPL below 100Hz as you shift your seating position), then you can use multiple subs. Unfortunately, that ramps up the cost and effort significantly.

thejck

well the original plan was to go with 2 seperate subs if you read through the thread. I like the idea of the smaller sealed subs so much better due to the waf.
however I am not that knowledgable on the matter. what would i use to take a sealed sub and allow it to go lower frequency in a room? using winisd putting in differnt drivers and cubic feet and all the tuning frequencies stay around 30. i want to go down to 20-18 if possible with a sealed. someone please enlighten me
also would it be better to go with a front firing or a dual side firing option.

jcandy

thejck wrote: »

well the original plan was to go with 2 seperate subs if you read through the thread. I like the idea of the smaller sealed subs so much better due to the waf.
however I am not that knowledgable on the matter. what would i use to take a sealed sub and allow it to go lower frequency in a room? using winisd putting in differnt drivers and cubic feet and all the tuning frequencies stay around 30. i want to go down to 20-18 if possible with a sealed. someone please enlighten me
also would it be better to go with a front firing or a dual side firing option.

You will never stay flat to 20Hz with a sealed 12. For that you will need active equalization. Here is a simple but impressive sealed design for the RSS315:

RSS315HF
Interior volume = 2.5 ft^3
Fc=37Hz
F10=20Hz
Qtc=0.78

I would build two of these. They will be excellent with music (better than any ported variant), and -10db at 20Hz is actually very nice. One option to simplify the build and keep costs down would be to use a single BASH 500W amp (in its own separate enclosure) and wire the subs in series. Or not.

If you must have even more extension I'd choose a different driver for a ported design. It will be larger, play louder, and probably sound less musical.

ben62670

Dude as a firm beleiver that we could only hear the 20-20k range I built a sub -3db at 15hz for HT. You can experience sub sonics that you can not hear. For HT go deep. As for music if you cross the XO at 60hz or less a sub will most likely be clean without distractions. Very musically.

jcandy

ben62670 wrote: »

Dude as a firm beleiver that we could only hear the 20-20k range I built a sub -3db at 15hz for HT. You can experience sub sonics that you can not hear. For HT go deep. As for music if you cross the XO at 60hz or less a sub will most likely be clean without distractions. Very musically.

I cross at 40Hz to a single sealed 15, which is actively equalized (FBQ 2496). I forgot to mention to thejck that once the subs are installed, an FBQ or other form of equalizer will allow some degree of smoothing and extending the in-room response.

Also, I absolutely agree that there will always be some tactile "holy cr@p" to a massive ported sub with a F3 in the teens. Pressure is pressure, even if at 10Hz. On the other hand, the trade-off in terms of (a) increased group delay, (b) increased enclosure volume, and (c) problem with room modes makes such a beast less attractive in my medium-size room. YMMV depending on room size, etc.

Nevertheless, if thejck says the sealed 12s are too tame and he needs 15Hz, then I can offer a crazy ported alternative.

thejck

ben62670 wrote: »

Dude as a firm beleiver that we could only hear the 20-20k range I built a sub -3db at 15hz for HT. You can experience sub sonics that you can not hear. For HT go deep. As for music if you cross the XO at 60hz or less a sub will most likely be clean without distractions. Very musically.

is this the sonusub you are talking about?
how big will it be. Maybe I need to scrap the end table idea.

thejck

jcandy wrote: »

I cross at 40Hz to a single sealed 15, which is actively equalized (FBQ 2496). I forgot to mention to thejck that once the subs are installed, an FBQ or other form of equalizer will allow some degree of smoothing and extending the in-room response.

Also, I absolutely agree that there will always be some tactile "holy cr@p" to a massive ported sub with a F3 in the teens. Pressure is pressure, even if at 10Hz. On the other hand, the trade-off in terms of (a) increased group delay, (b) increased enclosure volume, and (c) problem with room modes makes such a beast less attractive in my medium-size room. YMMV depending on room size, etc.

Nevertheless, if thejck says the sealed 12s are too tame and he needs 15Hz, then I can offer a crazy ported alternative.

I was going to do either a single 15 or dual 12's per sub. Dont know which configuration is better.
If I go ported would I be able to go dual 12's or single 12 and keep the size down compared to a single 15?
so if i go sealed I have to get a more powerful amp as well as some kind of eq. what about the amp that Face suggested. the 1000w rack mount amp that has some eq adjustments built in. Could I do that by itself or would I have to still add some additional eq?

thejck

what advantage would the TC sounds drivers provide vs the daytons if money was no object?

jinjuku

Depending on your level of 'adventure'. Danny at GR research may still have some 15" drivers used in the now defunct AV123 MFW-15's.

Call and see. I believe the price is $79.

They model to a 4.5 cubic foot sealed enclosure and an F3 at 23hz and F6 at 18.5 with a bit of EQ applied. If you want you can go 7.5 cubic feet ported with a tuning of 19Hz.

Get a Behringer Feedback Destroyer (has PEQ). The 1124 is ~$110, the 2496 is ~$160.

Get a 1000 watt amp at 4 ohms (500 per channel) and you will have plenty of head room.

So you are looking at $190-200 for drivers (shipping and all of that). $110-$160 for EQ, maybe $300-$350 in amplification for dual 15's either sealed (my personal preference) or ported. Another $90 in 11 layer baltic birch ply.

So for ~$800 bucks you will have a rocking setup.

jcandy

thejck wrote: »

I was going to do either a single 15 or dual 12's per sub. Dont know which configuration is better.
If I go ported would I be able to go dual 12's or single 12 and keep the size down compared to a single 15?
so if i go sealed I have to get a more powerful amp as well as some kind of eq. what about the amp that Face suggested. the 1000w rack mount amp that has some eq adjustments built in. Could I do that by itself or would I have to still add some additional eq?

First, let me say one again that the typical aim of the novice sub builder is to build a monstrosity that can crack the plaster but integrates poorly with the mains and interacts badly with the room.

That aside, I feel that dual 12's in a single enclosure largely defeats the purpose of a 12, which in my mind is to reduce the enclosure volume. Further, two 12s are nearly double the price of a single 15. Save your $$$ and use a single 15. Box size will increase to about 5 cubic feet, with Qtc=0.78, F3=31Hz, F10=15Hz.

Also, using active equalization (for example, one of the various Behringer products) helps not only to extend the response but perhaps more importantly to eliminate response peaks (the FBQ units apply localized filters to remove peaks). Actually, having two subs helps to smooth in in-room response, as mentioned previously.

Finally, to drive two separate 15s, a single Dayton SA1000 amplifier (the one suggested by face) is a very nice solution. It provides some degree of equalization that may be enough for your needs.

Ported versus sealed: again, if you must have super-low F3 then you'll need to choose either a ported 12, or a ported 15 (and not an RSS).

At this point, you need to choose between ported (very low F3 but with group delay and associated port issues) or sealed. Then, to choose between 12 and 15 will be a matter of SPL and size.

In going from 12 to 15, you get a bit more low-end extension, increased SPL, but will require double the enclosure volume.

thejck

Ok making progress here then.
I am going to stick to a single 15 per box and sealed. unless i can figure out dimensions for ported to make them fit where i want it to fit.
Is the velodyne sms-1 a better option for eq'ing the 2 subs. Can I EQ them both together? or do they have to have seperate eq'ing. I guess if i was running them off one amp then that answers that question but what if i go with sperate amps for each sub.

on a seperate note.
how come we dont see a lot of talk about using passives in your sub. Dont they give you the best of both worlds. Tighter for music and lower for HT. I know they have additional cost for the passives but dayton has some passives that are between 50-70 bucks out there. The advantage of being able to go with a smaller box would be benificial to me at least.
I can do a 12 inch active with 2 12/15 PR's in a box that is only 2.5 cuf.

For my room dimensions Face stated that it might be overkill to go with 2 of them. What if I went with 10 inch active drivers and 12 inch PR's?

jinjuku

thejck wrote: »

Ok making progress here then.
I am going to stick to a single 15 per box and sealed. unless i can figure out dimensions for ported to make them fit where i want it to fit.
Is the velodyne sms-1 a better option for eq'ing the 2 subs. Can I EQ them both together? or do they have to have seperate eq'ing. I guess if i was running them off one amp then that answers that question but what if i go with sperate amps for each sub.

Ideally each sub should have it's own EQ/Filters applied because generally they will be in different parts of the room.

thejck wrote: »

on a seperate note.
how come we dont see a lot of talk about using passives in your sub. Dont they give you the best of both worlds. Tighter for music and lower for HT. I know they have additional cost for the passives but dayton has some passives that are between 50-70 bucks out there. The advantage of being able to go with a smaller box would be benificial to me at least.
I can do a 12 inch active with 2 12/15 PR's in a box that is only 2.5 cuf.

For my room dimensions Face stated that it might be overkill to go with 2 of them. What if I went with 10 inch active drivers and 12 inch PR's?

PR's are a great way to do it but it is a cost factor that some will just shrug at and go with ported enclosures and let the footprint be damned.

jcandy

thejck wrote: »

Ok making progress here then.
I am going to stick to a single 15 per box and sealed. unless i can figure out dimensions for ported to make them fit where i want it to fit.

You can always build ported enclosures for the 15s in the future if the extension is not to your liking. Let's assume we are going with sealed.

thejck wrote: »

Is the velodyne sms-1 a better option for eq'ing the 2 subs.

A few years ago someone noticed that the SMS introduces alot of distortion; much more than the FBQ2496. You'll want to check up on that. But the equalization issue can be tackled after the subs are up and running.

thejck wrote: »

Can I EQ them both together? or do they have to have seperate eq'ing. I guess if i was running them off one amp then that answers that question but what if i go with sperate amps for each sub.

You'd want to equalize them together. Remember 2 subs will already work wonders for taming room modes. The challenge of separate sub eq has also been discussed on various forums.

thejck wrote: »

how come we dont see a lot of talk about using passives in your sub. Dont they give you the best of both worlds. Tighter for music and lower for HT. I know they have additional cost for the passives but dayton has some passives that are between 50-70 bucks out there. The advantage of being able to go with a smaller box would be benificial to me at least.

My impression is cost and convenience. To lowest order, a PR and ported sub are the same thing insofar as they exploit the same secondary resonance (I also fear that some box design software may not model PRs correctly). In the case that the box is large and the sub output is low, there would be no reason to use a PR, since porting is cheaper and easier. However, for typical enclosure volumes and SPL demands, the port has to be wide (to avoid port turbulence, also know as chuffing). But the wider the port (or the smaller the box, believe it or not), the longer the port must be for a given tuning frequency. So, you can quickly find yourself in a regime where the only suitable port needs to be 2 feet long! Then you need a PR.

thejck wrote: »

I can do a 12 inch active with 2 12/15 PR's in a box that is only 2.5 cuf.

Sealed 15 sounds much better and much cheaper to me. I am afraid an equalized 12 with dual PR in 2.5 cu ft will sound like crap (unless you're talking about hardcore active modification like with the Linkwitz transform). So now I am not sure what sort of equalization you mean.

thejck wrote: »

For my room dimensions Face stated that it might be overkill to go with 2 of them. What if I went with 10 inch active drivers and 12 inch PR's?

No. 2 active 10s will run out of excursion long before a single 15.

For most of this discussion I've assumed that you wanted to avoid complex active circuitry (i.e., I assume you didn't want to make a small high-Q sealed sub and then equalize it back to earth). My suggestion for equalization was only to remove room modes or suckout (its pretty standard for people to use Room Eq. Wizard in conjuction with, say, FBQ2496 for this). However, if you want to go that route you could start here by reviewing the Linkwitz transform:

http://sound.westhost.com/project71.htm