Best size(s) for reusable speaker cabinets / knock-down cabinets

[a4eaudio]

I am thinking of building some cabinets with a replaceable inset baffle where I could design different speakers and just swap the drivers in and out - remaking a face-plate or adding a speaker grill for the specific drivers. I would make several sizes but I have not built enough speakers to know what would be a good/useful standard size. I can always reduce volume so I would err on being too big and go with a baffle width that can handle the largest woofer that I might use + 3/4" roundovers.

In your building experience, what gross internal box volume and baffle width would be the most useful to you as a standard and how many sizes would be most useful to you?

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I don't think I want to build 6 sizes, but doing a little research, my initial thoughts of possibilities are:

1. Small Bookshelf 0.35 cf (10 L) 7.5" w baffle
2. Medium Bookshelf: 0.56 cf (16 L) 8.5 w (same as PE flat pack)
3. Large Bookshelf: 0.85 cf (24 L) 9.0 w
4. Small Tower: 1.16 cf (33 L) 8.0 w (same as PE flat pack)
5. Medium Tower: 1.75 cf (50 L) 10.5 w
6. Large Tower: 3.5 cf (100 L) 12.0 w

[Steve Lee]

You and I are headed in the same direction tonight.

I just designed and simulated an 8" wide by 13" deep by 32" tall cabinet [1.2 gross cu ft] utilizing an existing yet uncompleted set of cabinets that will dig to 33 Hz and up to 25 Khz and will be fully configurable on the baffles for a 3 way system - everything is done in sections so you don't have to remake an entire baffle for the 3 drivers. (Roughly 84 db, though . . .)

Keep going and you guys please chime in to a4eaudio's request for info/feedback.



Aside/ tonight's thoughts:

Nothing good/new/useful/revolutionary is created by committee.

The best inventions/creations come from a singularly focused mind and and its physical efforts seeking only that information it understands that others may provide and nothing more than that.

Tonight I have designed and planned out/simulated in software my next speaker build utilizing an existing pair of cabinets which have sat uncompleted for about 2 years- it is a fully configurable 3 way speaker test cabinet of around 1.2 cu ft of gross internal volume which should get me down to 33 Hz ~ 25+ Khz sound reproduction in an 8" wide by 13" deep by 32" tall cabinet [perfect for main speakers on either side of a 50" TV screen or music recording studio with live performers in a small/acoustically dead room].

Keep going . . .

[Whitneyville1]

"Bookshelf" speakers in about 14~16 liters (.5 cu. ft.) work pretty well with lots of 6"-6.5" mid-woofer (especially Tympany/Peerless). I haven't checked drivers available recently, but there were lots of great 5" mid-woofers that worked well in down to 7 Liters, but I think the trend has gone to one's working better in 10 Liter ported enclosures. I was looking for options for "bigger than a micro computer speaker, smaller than a breadbox" for desktop computer "monitor speakers", hopefully to fit into 7 liters and PE didn't have many options.
I could see building a 40 liter floor standing tower for a two or three-way design. Use sand bags to fill volume for a two-way. I'm not too sure how viable large towers are today, unless you have a mega-room. Multiple sets of two-way or 2.5 speakers and subs can actually image more accurately than two mega speakers as there are time alignment things that go on in a BIG room and high SPLs.
I think you could build THREE sizes of enclosures (small bookshelf, medium bookshelf, medium tower) and cover your experiments, but those are MY "wish list". If you have a different pick, have at it and have fun!

[Billet]

Depends heavily on the size of your listening room and how much you value deep bass. I've built 0.5, 0.75, and 1 cu. ft. I like the 0.5 size best, it is a good compromise and can fit a wide range of drivers from 5 to 8". YMMV...

[Chris Roemer]

Yeah, I'd probably condense 5&6 into maybe one size (2.0-2.5cf?) and make the 1.16 a bit larger (1.5?).
3.5 cf is a bit overbearing in most "normal" size (large) rooms. I made some 5cf'ers for a friend once, and they just got a nod of disapproval.

[rpb]

I reuse old boxes frequently. I cut them down sometimes. I stack two on top of each other sometimes to make a 3-way. Most of the smaller boxes eventually get thrown away. I want something that will work with 5.25" to 6.5" drivers. What I need is an easy way to alter the baffle so that I can replace it with a new one which can be glued on.

With that said. I find a 9" wide baffle pretty much ideal. For a sealed 2-way, a 9" x 14" baffle is handy. I like large round-overs, or facets, but not all my speakers have them. A sloped baffle is very handy too!

Most of the time, I have a sub for the deep bass. I have the urge to build ported 1.3 cu-ft towers for my living room, and not use a sub.

[a4eaudio]

"Bookshelf" speakers in about 14~16 liters (.5 cu. ft.) work pretty well with lots of 6"-6.5" mid-woofer (especially Tympany/Peerless).

I noticed Bookshelf was in quotes...I think better terminology for a 24 L (0.85 cf) non-tower speaker would be "stand-mount" as it wouldn't be going on a bookshelf.

I'm not too sure how viable large towers are today, unless you have a mega-room.

3.5 cf is a bit overbearing in most "normal" size (large) rooms.

Good points. I have an idea for a TMWW with dual 10" woofers...but I doubt I would have multiple ideas where having a REUSABLE cabinet this size would be particularly useful.

[Wolf]

I'm also planning a reusable cabinet. It is set at 22 ltrs, and I can reduce internal volume if need be. Maybe a card-slot for the xover mount, and double-ended bulkhead for connections out to in via banana.
I bought Neo magnets with screw-mounts to recess into the main box, and hopefully make changes easily. Just some washers epoxied to the back of the baffle, and a seal in between should do.

Wolf

[4thtry]

For the tower, my vote would go for 2 cu ft and 8.5" wide. This width is needed to accomodate 7" woofers and two 3/4" roundovers. Also, two cubic feet gives you enough room to parallel up two 8 ohm, 7" woofers , resulting in a finished speaker with 6dB greater efficiency that can still dig fairly deep. I would also suggest the use of non-parallel sides or tops to help distribute internal box resonances.

Bill

[a4eaudio]

For the tower, my vote would go for 2 cu ft and 8.5" wide. This width is needed to accomodate 7" woofers and two 3/4" roundovers. Also, two cubic feet gives you enough room to parallel up two 8 ohm, 7" woofers , resulting in a finished speaker with 6dB greater efficiency that can still dig fairly deep. I would also suggest the use of non-parallel sides or tops to help distribute internal box resonances.

Bill

After researching drivers and some of my "sims for fun" I am thinking of both a 1.7 cf width 9.5" width and a 2.8 cf with 10" width. The first allows a 3 way with a single 8" and the second a 3 way with dual 8" driver, based on estimates of the Dayton Reference, Reference paper and Designer 8" drivers.

[Wolf]

a finished speaker with 6dB greater efficiency that can still dig fairly deep.

Bill, while I know what you mean, this isn't entirely accurate. 2 woofers in parallel will have +3dB great power efficiency, and +6dB great voltage sensitivity.
Just for clarity's sake,
Wolf

[donradick]

"Bookshelf" speakers in about 14~16 liters (.5 cu. ft.) work pretty well with lots of 6"-6.5" mid-woofer (especially Tympany/Peerless). I haven't checked drivers available recently, but there were lots of great 5" mid-woofers that worked well in down to 7 Liters, but I think the trend has gone to one's working better in 10 Liter ported enclosures. I was looking for options for "bigger than a micro computer speaker, smaller than a breadbox" for desktop computer "monitor speakers", hopefully to fit into 7 liters and PE didn't have many options.
I could see building a 40 liter floor standing tower for a two or three-way design. Use sand bags to fill volume for a two-way. I'm not too sure how viable large towers are today, unless you have a mega-room. Multiple sets of two-way or 2.5 speakers and subs can actually image more accurately than two mega speakers as there are time alignment things that go on in a BIG room and high SPLs.
I think you could build THREE sizes of enclosures (small bookshelf, medium bookshelf, medium tower) and cover your experiments, but those are MY "wish list". If you have a different pick, have at it and have fun!

There is a design for a 7 liter RS150-4 speaker on FB by Javad Shadzi. Reportedly pretty good. I will probably build it.

[jhollander]

The med bookshelf, 15 to 16 liters, works great for most 2 ways with a 8.5 inch width, then add a bass bin. I'm trying not to use the same shape.

[4thtry]

Bill, while I know what you mean, this isn't entirely accurate. 2 woofers in parallel will have +3dB great power efficiency, and +6dB great voltage sensitivity.
Just for clarity's sake,
Wolf

Correct. Poor wording on my part. Just to clarify a bit further, two 8 ohm woofers in parallel would give an increase of +3dB electrically AND +3dB acoustically for a total gain of 6dB in SPL at the listening position. The 3dB loss in power efficiency would be due to the power amplifier heatsinks getting hot from driving a 4 instead of an 8 ohm load.

Bill

[a4eaudio]

The med bookshelf, 15 to 16 liters, works great for most 2 ways with a 8.5 inch width, then add a bass bin.

Thank you, that is useful.

I'm trying not to use the same shape.

I totally get this. My "normal" approach would be use actual measured T/S parameters, build a box the exact size needed and do facets, curves, etc. as I feel aesthetically. But at some point, I don't have enough rooms in my house or friends and family to give speakers to, so building a very nice cabinet with the full intent to repurpose with a different design and different drivers once a year allows me to try a lot of things without repeated cabinet building (which takes me forever).