Which drivers for highly custom, small enclosure?

[MAB]

the dual config should elim a lot of that. otherwise, the thing is small enough that maybe it doesnt need additional bracing? anyone can chime in here.

I like to glue scraps onto the inside (like the driver cutouts) to tame any modes on the panels that I imagine exist. I no longer do fancy bracing on small cabinets.
You built the cabinets out of gold standard materials, and it looks like a fantastic job. Bracing can be added, but I don't think you will hear the benefit, even if there is a benefit. And it's going into your home with shelves and walls and windows and floors and vents. You may be chasing stray room resonances and buzzes once you get it playing.

 

[Anonamemouse]

the dual config should elim a lot of that. otherwise, the thing is small enough that maybe it doesnt need additional bracing? anyone can chime in here.

I have built larger cabinets without bracing, but my walls were thicker. This is a relatively small cabinet plus you use opposing woofers, so I wouldn't worry about it.

 

[sigbergaudio]

11"? So the revelators?

 

[MarnixM]

Have you considered the air inside the enclosure is a non linear spring? so eventually as the air volume of the enclosure reduces it will become the dominant source of non linearity. Regardless I wouldn't worry about THD<10% in the frequency range up to 100Hz as its audibility is questionable, furthermore in domestic enviroments objects vibrating external to the speaker add both harmonicly related and non harmonicly related distortion (far more objectionable). I would worry more about maximizing output within the constraints of the system.

Alan Lofft, Ian Colquhoun and Tom Cumberland did a practical research to the audibility of THD distortion and concluded that at high frequency levels (> 5KHz) 1% distortion was a perceptive level. How lower the frequency how harder it is to notice the THD distortion. At low frequency levels (<500 Hz) distortion levels up to 10% were not detected by a random listing forum. Below 40Hz distortion could go up to even 100% before noticeable

Source: Alan Lofft, Ian Colquhoun and Tom Cumberland, “How Much Distortion Can We Hear With Music?” (2014), Colquhoun Audio Laboratories Limited LC,

 

[suttondesign]

smaller sub (dual opposed 9” scanspeak in new, larger enclosure) with book wrap.

 

[suttondesign]

final subs. thanks to all who gave advice. so far, i have ample power using parallel wiring into each minidsp plate amp wired for mono. i havent done rew yet.

 

[Anonamemouse]

Wow! That is an absolute awesome idea! I love the books!
I just might steal that...

 

[suttondesign]

Wow! That is an absolute awesome idea! I love the books!
I just might steal that...

get a good jigsaw and buy 14” tall books at a used book store. and some tubes of glue. i used the offcut hardcovers as plates on which to glue the L-shaped spines.

 

[suttondesign]

For those who wonder if it’s worth it, having multiple subs provide a solid, deep foundation to music is really cool. I’ve never had quite the weighty low end that 2 dual-opposed subs provide. The 11” scanspeaks barely have to work.

 

[mcdn]

can you share the driver part numbers and box dimensions you ended up with? Previous posts of yours mention 9, 10, and 11 inch drivers so not sure what you actually ended up with!

 

[suttondesign]

can you share the driver part numbers and box dimensions you ended up with? Previous posts of yours mention 9, 10, and 11 inch drivers so not sure what you actually ended up with!

hi. scanspeak 23w/4557t00 9” drivers in one sub, and 28w/4878t00 11” in the other.

using 3/4” baltic birch, the boxes measure 19-1/2” x 13” x 13”. the dsp amps are outboard in an adjacent closet.

 

[suttondesign]

finally got around to using REW on these subs. using a Linkwitz transfer to boost at 20hz, they play flat and loud to 20hz, crossed over with 4th order slope at 55hz to fill in where the mains have a room null in that region. interestingly, the corner sub causes the most trouble with a null in the listening positions about 8ft away, but the sub below the tv has a smoother response. together, they end up delivering a pretty smooth overall rsponse.

so, not necessarily cheap given the cost of the drivers, but extremely pleasing and all but invisible.