Looks really nice Steve. What design software is that? Very slick!!
You probably already know this, but I'll mention it anyway... Aperiodic vents are for flattening impedance at driver resonance, not so much for boosting bass. Unless you are using low damping tube amps, or pure current source amp, you may not need that - aperiodic port is less valuable for SS amps with very high electrical damping (low output impedance.) Do you mean to boost the bass response? If so you want a reflex port. But you seem to know what you're talking about so maybe you have the next big idea. rightonrighton
Aperiodic doesn't have much airflow, so you could put them on the back an inch from the wall with no consequence. A reflex has high velocity air so it needs room to breathe. Madisound sells plastic aperiodic ports premade, they are pretty good. Your speaker probably only needs one though, the second would not improve impedance any further.
If you are going sealed (with or without aperiodic port) limit your box size to Q .5. That's as big as your driver can make use of. That will give you lowest bass extension, and best transient response, lowest group delay, but it sounds kinda dry with a high damping SS amp. Good for tubes though. If you want a little looser, warmer more natural "musical" sounding bass with SS amp, then Q .57 is good. Q .7 is warmer still, and smaller, but you'll start to lose some bass extension and bass clarity, but it will sound "fuller." The cool thing is you can build the box for Q .5, then put some wood or foam blocks inside to increase the Q to experiment with the sound. When you find the right sound, glue them down. (Qts in a sealed box is dependent on internal volume.)
For sealed (aperiodic,) you don't want to stuff it full, despite what the loudspeaker cookbook and HT guys say. It will measure "better" with more stuff, but it will sound hifi sterile dead and loss of sensitivity. Just line 3 opposing walls with 1-2" fluff, so only 3 walls are treated, the other three are bare. Make one of the treated walls the rear, and keep the stuffing away from the driver so it is not damped by close stuffing. Experiment with the stuffing thickness. You'll quickly see how thick you want it. You just want to reduce inner echo, not mechanically damp the cone too much. Parts Express Acousti-Stuff works well, but real long haired wool is the best. I use the small handyman rolls of pink 1" thick FG insulation. You could also make "creative" bracing to serve as angled reflectors to scatter the inner reflections to allow less stuffing. Too much stuffing makes the sound gets dry and dull. If not enough, the internal echos can be heard.
Make sure your box walls are as vibration free as possible. Using composite construction is a good way achieve this, with one layer very hard and dense like baltic birch, steel, granite, (high resonant Q) and the other layer soft and dead (low Q) like MDF, plastic, lead
In theory, bracing itself does not reduce the vibration energy, it only increases the resonant frequencies, which helps the wood better damp itself, or moves the resonance above the band of that enclosure. Search this forum for post about bracing and enclosure resonance by member planet10 for some good info. Actively damping the walls via material choice is better than just bracing.... but it's also more work, more expensive and heavier... I have found single driver speakers to benefit from very quiet enclosure, then you can really hear the magic without the noisy box singing along. Plywood box with 1/4" mild steel sheets glued to the inside, plus braces should work pretty well. There are several good threads here about enclosure vibration damping.
Have fun and post some pics!
Rich
