[jliedeka]

I have a mixed use system (music/HT) and I'm currently using a HSU VTF 3.3. It is way more sub than I need. I can shake the room using a fraction of its power. For aesthetic reasons I'd like to replace it with two smaller DIY subs.

My living room is about 1500 ft^3 and my seating position will be roughly 2 meters from the subs so I don't really need a ton of power. My goal is clean tight bass but I don't want to give up room shaking explosions. I should also mention that I have some bass traps in the room, 3 GIK monster traps.

My question is how low does a sub really need to go? Does it have to be flat to 20Hz or extend down to subsonic frequencies? I'm not interested in reproducing subsonic organ music. I just want to get the most out of my home theater while improving music playback. Any suggestions for a realistic design goal? Any ideas about typical LFE frequencies?

Jim

 

[evilskillit]

I think this has been discussed before. When it comes to music and f3 of 30hz - 35hz is enough for 99% of music. However when it comes to movies the lower the better, if you really want to shake stuff I think you want at least try to hit high decibels at 20hz. Lower than that is nice but wether it is really needed or not is debated.

 

[lsiberian]

I have a mixed use system (music/HT) and I'm currently using a HSU VTF 3.3. It is way more sub than I need. I can shake the room using a fraction of its power. For aesthetic reasons I'd like to replace it with two smaller DIY subs.

My living room is about 1500 ft^3 and my seating position will be roughly 2 meters from the subs so I don't really need a ton of power. My goal is clean tight bass but I don't want to give up room shaking explosions. I should also mention that I have some bass traps in the room, 3 GIK monster traps.

My question is how low does a sub really need to go? Does it have to be flat to 20Hz or extend down to subsonic frequencies? I'm not interested in reproducing subsonic organ music. I just want to get the most out of my home theater while improving music playback. Any suggestions for a realistic design goal? Any ideas about typical LFE frequencies?

Jim

I'd suggest we start by seeing what you are getting from your current sub.

Still I'd say a pair of Narrow JL audio 8w7 builds could fill the bill easily. one of them might fill your needs.

Build them in a narrow 1.6 ft^3 tuned to 23 hz and use a folded port around the interior to get low port turbulence.

These are no ordinary 8 inch drivers and are capable of incredible spl in a room. They best many 12" drivers including the one I'm using in my sub. You can get a single driver for around 300 bucks each. If you want me to help further with the design I'd be happy to. Just let me know.

 

[Mike P.]

These are no ordinary 8 inch drivers and are capable of incredible spl in a room. They best many 12" drivers including the one I'm using in my sub.

Can you post the parameters of these "mini monsters"?

 

[evilskillit]

Some subs work really well in smaller boxes too. There is the Dayton Audio 12 Reference which needs a 3 cu ft box or bigger for nice low extension. However the Dayton Audio 12 High Output plays about as low in a 1 cu ft box with a small port. It will however require a bit more power for the same volume. Peerless also makes some nice 12s that work really well in small boxes.

 

[tonyvdb]

Uncompressed movie soundtracks from BluRay often have information down as low as 8Hz but if you ask me a sub that goes down to somewhere between 20Hz and 15Hz is plenty low for most people. There are die hards that want 10Hz but is it necessary? No.

 

[Mike P.]

I don't see the advantage of a 8W7. Compared to a SDX10 it has the same output in the same size box and tuning. The SDX10 is one third the price and has a XBL2 motor.

 

[evilskillit]

Hrm, yeah the CSS SDX10 Models just as well or better than the Dayton RSS315HO. You can put more power through the Dayton driver but if you're only using 300 watt plate amps anyways it doesn't matter the SDX10 seems to be the better bet. I know CSS makes pretty good drivers but I didn't expect the 10 to end up being the better solution. Either one will get you into the mid 20s fairly effectively.

There is also the Elemental Designs 11Kv.2 also models about the same in the same size enclosure and is $50 cheaper than the SDX10 so that might also be a consideration for a pair of small ported 10s.

 

[fredk]

When it comes to music and f3 of 30hz - 35hz is enough for 99% of music.

But not for the pipe organ. You want to reach at least 20Hz.

How big it the VTF3?

I don't know if you would consider the CSS Quartet kit small or not.

 

[fredm]

21.5”(h) X 17”(w) X 25”(d) is what the OP has for a current sub size. The 70 liter box suggested so far is really not much smaller. I guess less than one cu ft smaller once you account for the port and bracing.

If you prefer to have a much smaller sub you will give up a bunch in room vibrations. 21.5x17x20" sub would be very small and to perform well it would cost more than your current sub.

A Shiva-X could fit in the 70L box also but I think that is too big for you right?

 

[jliedeka]

Thanks for the responses so far.

I would like to get significantly smaller than my HSU. In the commercial market, I've been interested in the SVS SB-12 Plus, a small 12" sealed sub. A pair of those might be really close to what I'm looking for.

I do want to go DIY, however. I'll probably use a pro rackmount type amp for power. The thinking there is I'll want to use a Behringer DCX for crossover and EQ. I'll also be able to choose an amp (or two) with plenty of power.

Ideally I'd like a sealed, critically damped alignment but I don't think that will be workable with my desire for a small box size. I want to make a very well braced box.

My priorities are in this order:
1. the fastest possible transients
2. the flattest possible in-room response with f3 at or below 20Hz - assuming that's the right target
3. the smallest size consistent with 1 and 2
4. preferably with a budget of $500 per sub or less not including electronics, I'm willing to spend more if the quality difference is worth it.

Jim

 

[evilskillit]

Boy you aren't asking much for $500 are you :R

Tho if you aren't including the cost of electronics just the driver and MDF that might be doable. What you need is a driver with as much stroke as possible and as low VAS as possible. Then you'll need to model it and see how small a cabinet you can put it in. Then you're probably going to have to EQ the out of the low end and feed it lots of power. That is going to require more money in electronics than a lot of the alternatives but it sounds like you're ok with that.

Later when I've got some time I'll look for subs that might fit the bill and model them to see if I can make a sugguestion however in the mean time you can look around. Remember high Xmax, low VAS. The Shiva-X2 might fit the bill. Not sure. Also the LMS Extreme that Partsexpress has on clearance for approx $500 might work well for that, it is a performance car audio sub that is designed for small enclosures and extreme excursion.

Oh you'll also the lower the FS the better, but I think that is a lesser consideration.

 

[jliedeka]

Maybe I should reconsider the requirement for smaller subs. I think having a smaller footprint is a more important goal. A bass bin type of form factor might make more sense. I would just need to pick the right height for monitors to sit on top. That would probably give me more flexibility.

Jim

 

[fredm]

If you are willing to EQ you can make as small of a sub as you want. Just get a sub with good excursion then EQ it to make it sound how you want in a small sealed box.

If you seriously want to spend 500 per sub then get some JL 12w7's (or 13w7 if you can spend more). It has more Xmax and could go lower than the Shiva and look cooler, costs ~ twice as much. I have no idea about sound quality I am no expert but I seriously doubt it would be worse.

The 12w7 has a piston area of 84in^2 vs ~78in^2 for the Shiva (107 for the 13w7) and it has a longer xmax. (32mm for 13w7, 29mm for 12w7, 26mm for Shiva-X)

This means more displacement.

Don't give up on the dream, lol

 

[lsiberian]

Why not pick up the Audiopulse Axis 12" going for 400 bucks at parts-express? They are amazing drivers.

FYI the JL Audio 8w7 is very conservatively rated and has excellent sound quality(pure SPL isn't as important as SQ IMO). Plus it allows for a narrow box due to it's 8" size.

 

[jliedeka]

My main concern, above all else is sound quality. I really am concerned with frequencies below 60Hz. The speakers I'm building should allow for a lower than normal crossover.

How much will room gain factor in to the design? Since I have a small room - 12' x 16' x 8' - can I shoot for a higher f3 and still get plenty of bass?

Jim

 

[lsiberian]

My main concern, above all else is sound quality. I really am concerned with frequencies below 60Hz. The speakers I'm building should allow for a lower than normal crossover.

How much will room gain factor in to the design? Since I have a small room - 12' x 16' x 8' - can I shoot for a higher f3 and still get plenty of bass?

Jim

For frequencies lower the 60hz there is no reason to build 2 subs unless you are a symmetry kind of person. A single sub should do the trick.