Hi kneadle. If a speaker is underdamped, it will ring on transients. If it is overdamped, it will have a slow rise time.
So if you take a 1.5 v battery, connect on side to the speaker, and tap the other side from the speaker to the other side of the battery, it will go click if correctly damped on each make or break of the circuit. Bonk if its overdamped and boinging if its underdamped.
That's a trick from the days of full size BRs where the port was about 80% of the piston area, and damping adjusted with muslin cloth stretched accross the port.
So if you take a 1.5 v battery, connect on side to the speaker, and tap the other side from the speaker to the other side of the battery, it will go click if correctly damped on each make or break of the circuit. Bonk if its overdamped and boinging if its underdamped.
That's a trick from the days of full size BRs where the port was about 80% of the piston area, and damping adjusted with muslin cloth stretched accross the port.
I have found a similar concentric tl. This one is tapered, and a little bigger than my first attempt. 2'25 metres high, down to 10 hz.
Altec 3182, Subwoofer. 18" 300 w 92 db/w voice coil diam 3" Fs 18Hz
Vas 35 cu.ft!! Qts .4 Re 6.4ohm Xmax (one way) 0.5"
www.audioheritage.org/vbulletin/showthread.php?t=12126
Altec 3182, Subwoofer. 18" 300 w 92 db/w voice coil diam 3" Fs 18Hz
Vas 35 cu.ft!! Qts .4 Re 6.4ohm Xmax (one way) 0.5"
www.audioheritage.org/vbulletin/showthread.php?t=12126
Hello all, First, let me thank you all for the interest and suggestions offered, on this and other posts.
I thought about Onur's suggestion regarding thin carpet. A bit tricky now that every thing is assembled. But I thought I'd try lightl stuffing the tube in stages, leapfrogging the two TLs. I ended up with the inner tube lightly sluffed (small pieces of tontine dropped in) and the outer tube 1/3 full, again lightly stuffed.
They sound really good now, with very little midrange from the port, and nice extended bass. They do like to be on the floor, and near a wall, and no BSC as yet. Turning the in off axis partially cures that
I don't normally use tone controls, but last night while doing all this I hooked up to a NAD 120, just to get an FM program. The TLs respond well to bass boost, none of the woody muddyness sometimes heard.
I thought about Onur's suggestion regarding thin carpet. A bit tricky now that every thing is assembled. But I thought I'd try lightl stuffing the tube in stages, leapfrogging the two TLs. I ended up with the inner tube lightly sluffed (small pieces of tontine dropped in) and the outer tube 1/3 full, again lightly stuffed.
They sound really good now, with very little midrange from the port, and nice extended bass. They do like to be on the floor, and near a wall, and no BSC as yet. Turning the in off axis partially cures that
I don't normally use tone controls, but last night while doing all this I hooked up to a NAD 120, just to get an FM program. The TLs respond well to bass boost, none of the woody muddyness sometimes heard.
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