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

[Steve Lee]

Absolutely correct which is why I chose the cabinet that I had (1.2 cu ft gross) 8" W X 32" T X 13" D.

This will work in my living room for mains on either side of the TV and in my drumming room in the basement - internal volume is easily modified smaller to accommodate different drivers as needed.

[a4eaudio]

jhollander - my problem is that I am new to the hobby and 10 to 20 years behind you and Dan. (dlneubec I recently found a 2008 post "Simple DIYable Waveguide testing (dome tweeters)" that did something I am experimenting with now.) I have designed one speaker and am still voicing my second. I am trying to accelerate the learning curve - in 20 years I won't be able to lift tower speakers and won't be able to hear above 9Khz.

My idea of reconfigurable cabinets are NOT unfinished MDF prototype boxes. I plan on piano gloss white, piano glass black, curved zebrawood satin and curved bubinga gloss. They will look good, but obviously I can't experiment with different shapes. I have some ideas that do require a unique cabinet, but I also want to simply experiment with different driver combinations. I have found (like almost everyone else here) that it is easier to buy drivers than to build speakers, and now I have a basement full of drivers that I'd like to play with but it takes forever (for me) to build cabinets.

[rpb]

At some point, you design for the room, and location of the speaker in the room. For me, I'll never be happy with any speaker that is positioned close to a wall. A pair of 6.5" 2-ways in ported 1 cu-ft boxes will get the job done nicely in my living room. Larger speakers will work even better, but tend to dominate the look of the room, which is OK, except that I usually make plain looking boxes.

[Steve Lee]

For me, having a reconfigurable cabinet is so I can get the design/speaker combo right 1st then put what works into and interesting, expensive, time consuming cabinet.

It is still very interesting when you look at it from that perspective, isn't it?

[jhollander]

I think if I was to only build something that was to be repurposed or go in a standard cabinet I would lose interest very fast. dlneubec and I has the discussion that if we couldn't build something new and interesting we would not enjoy the hobby.

[Steve Lee]

^ exactly.

[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).

[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

[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.

[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.

[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

[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.

[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

[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

[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.