For home use, the PSD2002 could probably be crossed as low as 500Hz on the 511B. Much more clean low frequency output below 800Hz than the BMS 4550, but the upper output is not as smooth or extended.
A comparison of the two (PSD2002 orange, 4550 Blue) on a 13 degree conical horn:
I found the variation between PSD2002 units has been pretty large, the unit above was one of the better of four tested.
Art
Yes, what Art says.
I just dug up some old measurements of the 811 and 511. I didn't do much with the 511, but my measurements show that the 811 with an Altec 802 or 806 driver that 811 will play nicely down too 500Hz. That was with a 2nd order high pass at 350 Hz. The 802 was flatter and went higher than the 806, distortion was a little lower.
Also found a crossover diagram for the Lounge Lizards, but the values make no sense. Still looking. But anyway, finding a decent driver for your 511 and crossing it around 700-800 should be easy.
I just dug up some old measurements of the 811 and 511. I didn't do much with the 511, but my measurements show that the 811 with an Altec 802 or 806 driver that 811 will play nicely down too 500Hz. That was with a 2nd order high pass at 350 Hz. The 802 was flatter and went higher than the 806, distortion was a little lower.
Also found a crossover diagram for the Lounge Lizards, but the values make no sense. Still looking. But anyway, finding a decent driver for your 511 and crossing it around 700-800 should be easy.
What frequency range and slope are you using on the 250 driver? I have some I was considering using from maybe 450 to 5K.
Yeeks. Didn't expect that. Actually I heard them in a PA cabinet with crossover properly done, and they sounded good, maybe on the dark side, but good.
Ana experience with Celestion CDX 1745?
I've head the CDX 1745 in a Hi-Fi. I liked it. But a much smaller horn than the 511 and it must have been crossed 1200 or above.
It's done active so it's either 24 or 48 dB and xo would vary as I tend to use them 'by ear'. Usually between 600 and 1k. Then the top takes over at about 4-5k
Is there a bolt on version od 250 or do you use adapter? Because I've seen only threaded version.
Definitely not 'HIFI', been there, done that and while the myriad tweaks/mods got them close enough by all but the most critical (females with their superior HF hearing), it was just too labor intensive and nowadays can get 99% by judicious use of open cell foam and some duct seal or similar damping.
Here's a cross section of the Altec 1", which shows its internal conical horn, so ideally find some old European ~copies or without it the horn dies above ~8 k - 12 kHz depending on how much it's shelved, though of course you could make an adapter or if using a super tweeter, then XO at ~3.5 kHz.
While rated for a 500 Hz XO, this is based on being on a 2x mouth area baffle and driven with a high output impedance (low DF) amp, so for SS (high DF), best to either use a steep XO or up it to at least 700 Hz for < ~10 W or 1.2 kHz continuous for max driver rating due to its conical/expo re-entrant joint acting as an acoustic choke, making it basically just a hybrid WG, i.e. most 'HIFI' variant.
Hmm, with a 1.3 kHz minimum, I presume he's using them at Altec's 1.2 kHz prosound rating XO or needs to de-rate it to ~11 W/500 Hz XO if I remember the math right.
If 20 W/500 Hz is acceptable, then should work fine based solely on its published specs, though historically one has to really like JBL's Ti 'sound' [like shredding sheet metal to me, i.e. makes my teeth hurt 🙁] to me] as it will really 'come alive' in Altec's sectoral horns, so may need a Dr. Geddes style foam insert to tame it somewhat, then use EQ to 'lift up' its extreme HF for top end 'air' if no super tweeter is used.
@Sealed , @GM ,
The 2425 motor is a good investment in my opinion.
The 2425 with an aluminum diaphragm installed ( from Radian ) is actually an excellent sounding combo.
The biggest problem I see ( with recommending this combo to anyone ) is that installing the diaphragm ( is very fiddly & ) takes quite a bit of skill ( using things like REW and a test mic ) to really nail ( for best linearity ).
The Radian diaphragm is built along Legacy Lansing specs and will reach quite low.
FWIW, a Ti diaphragm working through a plastic // fiberglass // or wood horn is a whole different ballgame in sonics at HiFi levels ( when compared to almost any untreated JBL Ti's mated to any Altec metal horn, which to my ears = resonances*squared ,, IMHO, of course ).
🙂
The 2425 motor is a good investment in my opinion.
The 2425 with an aluminum diaphragm installed ( from Radian ) is actually an excellent sounding combo.
The biggest problem I see ( with recommending this combo to anyone ) is that installing the diaphragm ( is very fiddly & ) takes quite a bit of skill ( using things like REW and a test mic ) to really nail ( for best linearity ).
The Radian diaphragm is built along Legacy Lansing specs and will reach quite low.
FWIW, a Ti diaphragm working through a plastic // fiberglass // or wood horn is a whole different ballgame in sonics at HiFi levels ( when compared to almost any untreated JBL Ti's mated to any Altec metal horn, which to my ears = resonances*squared ,, IMHO, of course ).
🙂
I made the adapter using pole mounts, cork gaskets, and doing things the 'Cal' way.
