What is the best type of subwoofer?

medium jim · « **on:** 11 Jul 2012, 04:29 am »

This isn't a priced be damned question, rather the best bang for the buck question. Please explain and justify your responses.

Jim

JLM · « **Reply #1 on:** 11 Jul 2012, 09:40 am »

If you own (or are buying) a house, IB (infinite baffle) is the cheapest route. Shoot for 4 - 10 times the stated Vas for the driver. Beware of what's on the backside (sound goes both ways, hinged doors can slam closed and blow the cone out). Spare bedrooms, attics, garages, unfinished basements, large closets, unfinished cavities can all work, or even outdoors (weather/vermin protected) can work if crossed over low enough to not bother neighbors. Just add the amp.

Check out:

http://home.comcast.net/~infinitelybaffled/
http://ibsubwoofers.proboards.com/index.cgi

JLM · « **Reply #2 on:** 11 Jul 2012, 10:01 am »

If you don't own your place, consider MLTL (Mass Loaded Transmission Line) bass. If done right (search for Martin King's MathCad application) they are fast, musical, powerful, exhibit roll-off that complements room gain, and can go really low.

I had a pair of 8 inch passives in 6 c.f. cabinets that were rated to 114 dB at 17 Hz that sounded incredible, but only in a huge space (20,000 c.f. was glorious with 20 wpc), so I'd shoot for 5 or 6 inch woofers.

JohnR · « **Reply #3 on:** 11 Jul 2012, 10:25 am »

I can't build an IB, although I wish I could. If I put it under the floor, the neighbours would get as much of the benefit as I do (my house is on piers, no basement). If I put them in the roof, a bedroom has to get turned into a listening room, and the roof is only tin, so again, unhappy neighbours.

I suppose my answer to the question is that the best "type" wrt bang for the buck is DIY. I'm always a bit surprised when I see prices of commercial subs. If the question is then should they be ported, sealed, OB, IB, etc, really, it depends on what you want them to do. Any of these can be great. You will get people - "experts" - who will tell you what's wrong with this or that. But you know, they always have a barrow to push.

*Scotty* · « **Reply #4 on:** 11 Jul 2012, 06:58 pm »

I have to agree with JohnR that DIY offers the biggest bang for the buck. If you use a Parts Express box and sealed alignment you can get low bass without lumps from a misalignment that can occur with a reflex type enclosure. Parts Express is now carrying ClassD plate amps which offer the potential for very well defined bass from you DIY sub.
Both of the subs I am using to reduce the magnitude of the standing waves in my listening room are DIY. I have to go on record here and state that if you use a plate amp for your DIY sub, don't install it in the box. If and when it has a problem or fails, it will be much easier to repair or replace. You don't have to worry about matching the hole you cut in your sub with a differently shaped replacement plate amp.
Scotty

Wayner · « **Reply #5 on:** 11 Jul 2012, 08:52 pm »

This is different from the others responses, but what the heck. My point would be the construction of the sub-woofer. I think the best sounding ones, the ones that blend in the best have a downward firing driver. If you have a forward firing driver, it can become "locatable" and then that fix would be another sub-woofer, which then in turn could over-power, and unbalance an otherwise, nice 2 or multi-channel system.

My 2 cents worth.

Wayner

ricardojoa · « **Reply #6 on:** 11 Jul 2012, 09:30 pm »

Quote from: Wayner on 11 Jul 2012, 08:52 pm

This is different from the others responses, but what the heck. My point would be the construction of the sub-woofer. I think the best sounding ones, the ones that blend in the best have a downward firing driver. If you have a forward firing driver, it can become "locatable" and then that fix would be another sub-woofer, which then in turn could over-power, and unbalance an otherwise, nice 2 or multi-channel system.

My 2 cents worth.

Wayner

I think a downfiring sub has its advantage, but a front firing has its own too. You can rotate the direction where the firing is. Localization depends on how low the cut off is i would say.

*Scotty* · « **Reply #7 on:** 11 Jul 2012, 10:16 pm »

Some of the problems I have encountered with localization can be directly blamed on the 12dB/oct Butterworth filters commonly used in a great many sub-woofers crossovers. It would be nice if the mfgrs. spent $5 more to implement a higher order network and used a Bessel function to derive the filter coefficients instead of the ubiquitous Butterworth function.
The downward firing sub has an advantage in that the higher frequencies that may be passed by the xover are attenuated by the design. This can help it disappear more effectively.
I prefer a front firing sub to facilitate the generation of an accurate planer wave-launch into the room. This can greatly improve the bass impact felt at the listening position from percussion instruments. I admit that I am looking to crack plaster when it is necessary for the realistic reproduction of the music.
Scotty

PMAT · « **Reply #8 on:** 11 Jul 2012, 10:50 pm »

"I admit that I am looking to crack plaster when it is necessary" !!!!! I love that statement.

How about chest compression from a whack at the drum. In my Pink Floyd DVD there are some Bass passages that torture my room and furniture. Love it.

Russell Dawkins · « **Reply #9 on:** 11 Jul 2012, 11:47 pm »

Quote from: JohnR on 11 Jul 2012, 10:25 am

I can't build an IB, although I wish I could. If I put it under the floor, the neighbours would get as much of the benefit as I do (my house is on piers, no basement). If I put them in the roof, a bedroom has to get turned into a listening room, and the roof is only tin, so again, unhappy neighbours.

I suppose my answer to the question is that the best "type" wrt bang for the buck is DIY. I'm always a bit surprised when I see prices of commercial subs. If the question is then should they be ported, sealed, OB, IB, etc, really, it depends on what you want them to do. Any of these can be great. You will get people - "experts" - who will tell you what's wrong with this or that. But you know, they always have a barrow to push.

I wonder if you would get some useful neighbourhood cancellation with the rear radiation from a bass driver IB mounted in the floor cancelling some of what leaks out of the room, both being in opposite polarity. You might be able to enclose it somewhat in a large enclosure with an adjustable resistive aperture so you could vary the amount leaking out until it matched what was leaking from the room above and cancelled more completely.

It wouldn't cost much to find out.

JohnR · « **Reply #10 on:** 12 Jul 2012, 05:11 am »

It's easier to just use a dipole inside

jimdgoulding · « **Reply #11 on:** 12 Jul 2012, 07:52 am »

Quote from: *Scotty* on 11 Jul 2012, 06:58 pm

I have to agree with JohnR that DIY offers the biggest bang for the buck. If you use a Parts Express box and sealed alignment you can get low bass without lumps from a misalignment that can occur with a reflex type enclosure. Parts Express is now carrying ClassD plate amps which offer the potential for very well defined bass from you DIY sub.
Both of the subs I am using to reduce the magnitude of the standing waves in my listening room are DIY. I have to go on record here and state that if you use a plate amp for your DIY sub, don't install it in the box. If and when it has a problem or fails, it will be much easier to repair or replace. You don't have to worry about matching the hole you cut in your sub with a differently shaped replacement plate amp.
Scotty

Likewise bout DIY. That has to be the most gratifying. Might even lead to a business. Being a consumer won't, I shouldn't think. Regardless.

WireNut · « **Reply #12 on:** 24 Jul 2012, 12:36 am »

I've had several ported subs/bass cabs over the years driven from active xovers.
Some with a single 18 and some with dual 12".
For fast/tight bass IMO sealed is the way to go.

JohnR · « **Reply #13 on:** 24 Jul 2012, 10:35 am »

Quote from: Wayner on 11 Jul 2012, 08:52 pm

This is different from the others responses, but what the heck. My point would be the construction of the sub-woofer. I think the best sounding ones, the ones that blend in the best have a downward firing driver. If you have a forward firing driver, it can become "locatable" and then that fix would be another sub-woofer, which then in turn could over-power, and unbalance an otherwise, nice 2 or multi-channel system.

I think that one depends. Certainly, in my house, a downward-firing (or upward-firing, for that matter) subwoofer is a disaster. Opposed "push pull" drivers are by far the best option.

WireNut · « **Reply #14 on:** 24 Jul 2012, 03:36 pm »

Push/Pull designs are interesting to me but with my current 8ohm drivers running in series that would be a 16 ohm loud. If i owned 4ohm drivers push/pull would be a design I would like to build.

JohnR · « **Reply #15 on:** 24 Jul 2012, 03:38 pm »

Without knowing any specifics of your system, you can put 8 ohm drivers in parallel to realize a (nominal) 4 ohm load.

WireNut · « **Reply #16 on:** 24 Jul 2012, 03:50 pm »

Wired in parallel seems like it would no longer be push/pull.

JohnR · « **Reply #17 on:** 24 Jul 2012, 03:56 pm »

Consider the physical movement of the cones. If one cone is moving in one direction, and another cone (in an identical driver) in the opposite direction, then the physical force will (mostly) cancel - the purpose being that the physical force exerted on the cabinet and anything that it is connected to (like the floor) is minimized.

Whether the two drivers are wired in series or parallel makes no difference as far as physical force cancellation is concerned.

Chromisdesigns · « **Reply #18 on:** 24 Jul 2012, 03:59 pm »

How much space ya got?

Nelson Pass thinks highly of these...not sure his neighbors would agree!

http://www.passdiy.com/pdf/el-pipe-o.pdf

WireNut · « **Reply #19 on:** 24 Jul 2012, 05:36 pm »

Just did some modeling for my drivers. Swan (hi-vi) W12's.
Push/pull looking very promising.
This is what I've come up with.
2.5 L push/pull compound vented cab (that's 1/2 the size of a sealed box) = -3db at 27.5 Hz
5.3 L sealed cab is -3db at 56.5 Hz.
SPL with 100 watt input is 105 db at 27.5 Hz for the PP.
SPL at 100Hz for sealed is 113db / push pull is 108db (that's 5 db lower at 100Hz for the PP).
Group Delay rizes to 23 msec's at 22 Hz for the PP box. Not sure if that's a problem.

Where's Nelson when I need him.