Dear Pano,Originally Posted by Panomaniac
I am sure you have noticed the complex room correction... (behind the speakers and on the side walls). I sent a message Semelec to check if it is possible to listen the A5.
Last edited by dominique-tanguy; August 15th, 2011 at 04:05 PM.
Altec 825 (515-8G) Altec 1505B (291-16A) IWATA 600(GPA 802-8G) + Mark Levinson No. 29 - Kenwood KD-8030 - DAC Dangerous Source - J-River
Thanks Dominique. Yes, I noticed the room treatment straight away. I like the DIY Schroeder diffuser on the wall. And the use of carpet pad around the corners, too.I hope to build a diffuser something like that. It would not be too expensive, unless I want to make it pretty.
But isn't those 1505's too big for a room that narrow ? Even with the treatments IME there would be a tremendous amount of room reflections due to the narrow aspect of this room ? The treatments would have to be 360 degrees meaning all 4 surfaces walls,ceiling,and floor to even come close in damping the reflections ? IMHO I think a 311-60 would be perfect for that room. Dunno whadda ya think guys ?
Horns IMO are all about mating them to the correct application.
You are absolutely right!
That is a small room for those horns. I never used them in a space that small, so can't say what it would sound like. I'm in a slightly wider and taller space with 1005s. Wall treatments help!
Last week I finally came up with a crossover that works well for my system and I think it will stay. It's 800Hz, 4th order acoustic. Electrically it's different - to achieve that acoustic target. It ended up there because every time I found a good sounding x-over, the horn (288-8K+1005) was at 800Hz, 4th order acoustic (Butterworth). So I figured "if that's were the horn wants to be, let it stay there." I could get it to play lower, but there was more distortion out of the horn down low than the 416 up high, so why force it?
Next I set out to find an electrical x-over point that would give me my 4th order HP at 800Hz - and then bring in the woofer to meet it. For those of you who know filter slopes, you will know that 4th order Butterworth does not sum flat. Spreading the points apart can give you a flat summation at the crossover point, so that's what I did. Left the horn at 800Hz were it's happy and rolled the woofer down to 650Hz (acoustic). That spread of about 22% is typical and gives a pretty flat response.
The next step was to find the electrical points that would give the drivers their 650Hz and 800Hz acoustical slopes. Measure, change, measure, change. Where they ended up was: Woofer LP = 545Hz, 3rd order and Horn HP = 850Hz, 3rd order. Those electrical slopes resulted in the target 650 & 800 Hz acoustic slopes (with my drivers, horns, cabinets). Shifting the horns back and forth a bit got them into phase.
The 288/1005 combo rolls off on top at about 7Khz with a break-up peak at 11Khz. I use a pair of Fane bullet tweeters on top to fill in. They don't quite reach down to 7Khz, so there is a dip between the 1005 and tweeter.
See below the response of one side at a distance of 5 feet.
As nice as this looks, it does not sound right when both speakers are playing. In the next post I'll tell you why.
I'm admittedly a novice at speaker build/design, but I'm guessing you'll want to use a tweeter that will play down to 7k (and preferably also doesn't roll off at 17k) to eliminate that dip between 7k and 10k. I would think that dip would be noticeable. Other than that (and the "floor bounce") the response curve looks nice............. The 288/1005 combo rolls off on top at about 7Khz with a break-up peak at 11Khz. I use a pair of Fane bullet tweeters on top to fill in. They don't quite reach down to 7Khz, so there is a dip between the 1005 and tweeter.
See below the response of one side at a distance of 5 feet.
As nice as this looks, it does not sound right when both speakers are playing. In the next post I'll tell you why.
Last edited by voice of the theater; August 28th, 2011 at 04:44 PM.
Being of "Sound" Mind
Yes, you've got it right.I'm trying to find a tweeter that will reach down lower, but still keep up with the 288/1005. I have to bring the mids down 7-10dB to match most tweeters I have. I may try the Eminence ATP next. The roll off at 17K I don't care about, I can't hear it now anyway. And when I could hear it, it just annoyed me.
I've a similar arrangement, though 515-8G's.Yes, you've got it right.
Experimenting with some EV XEQ-808's at the moment and the 288 are heavily padded with it.
RE tweeters: Some I've tried listed below, if looking for additions to a short list.
Experimenting with the HF has been low priority for me, so experience and thus comments are minimal. No measurements on my end to be had atm.
Aurum Cantus G1 (spec'd: 103db, $$$, too directional :-( )
GPA 902-16A:
Beyma CP09: PW Buyout iirc. Cheap at the time. 104db spec'd
Selenium ST-324
multiple piezo's in an array...
ummm.... I think that's it.
How did the piezo's sound? I have 8- 3" super tweeters artfully ducktaped onto each of my 511b's and think they sound fine, but I don't really know, I’m a low brow stereo aficionado. I wired them up wrong however thinking that I had to worry about too low of an ohm load on the amp, so I have them wired up in parallel and in series which I now realize I didn't have to and should have just wired all of them in parallel.
Last edited by VolvoHeretic; August 31st, 2011 at 03:04 PM.
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