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Old 17th February 2011, 12:14 AM   #31
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Quote:
Originally Posted by AcoustatAnswerMan View Post
Only 1/2 of one panel width is run at full range in any Spectra model, the rest of the panel area is mid/lows or lows only. Spectra panels can be used in non-Spectra applications, and I consider it optional to tie the ends of the split stators together. Connecting both wire leads together (white-to-white and blue-to-blue) will make the stator all the same circuit.
Sure Andy - but the question is IF the distance between the two HF sources, that being the 1/2 of the cell to the adjacent cell's 1/2 cell is more than or multiples of a 1/4 wavelength, then the potential for nasty horizontal polar response comb filtering exists. That's the concern I was voicing.

_-_-bear

PS. can you post a copy of the 9500 schematic up here?
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Old 17th February 2011, 04:08 AM   #32
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Originally Posted by bear View Post
PS. can you post a copy of the 9500 schematic up here?
Here is the schematic for the 9300/9500. Quite the heat generators even at idle as I recall.
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File Type: jpg hafler_9500.jpg (128.0 KB, 717 views)
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Old 17th February 2011, 03:21 PM   #33
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Originally Posted by AcoustatAnswerMan View Post
The angle-between-panels varied over the years, with some of the later models (i.e. 2+2) having less angle than an earlier Model 4. I believe the final angle was about 9 degrees between panels. Of course the Spectra Series had no angle between panels, since the panels were electrically curved (convex when viewed from either side!)

The combination of 8" and 9" panels was an effort to 'spread-out' the low frequency resonant point, the 8" being a slightly higher frequency. If all you have are 9" panels, I would not let that stop you from building a Model 8-like design. Note that the 8" panels were used only in 3-panel and 4-panel wide systems, like the Model 3, 4, 6 and 8. The 2+2 and all of the larger Spectra's (even the mighty 66/6600) did not use the 8" panel.
Thanks, Andy. What I'm planning on doing is building some sort of framework to hold a 4 panel-wide array which has the ability to allow the panels to have some rotation in order to try and ascertain the best panel angles in my room. I was curious if Acoustat did something similar to arrive at these angles. I have a few ideas in mind, but if there is an existing way of doing this I'll take that under advisement. The plan is ultimately to determine the best angle results from the adjustable 4 panel framework, then build a double-height (8 panels) rigid frame (braced to the ceiling) from these results. Any thoughts?
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Old 17th February 2011, 05:44 PM   #34
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I used piano hinges, the length of the cells, with a thin MDF strip the length of the cells, but only as wide as the "dead" area on each edge to mount the piano hinge to... not perfectly ideal, but it did work nicely for my "space frame" Model IIIs... I did get a deal on very long piano hinges... and in the III the center panel is fixed rigid mount... it does get the cells closer together than the stock frame can.

IF you take the acoustats outside, you will likely find as I did just how beamy they are!
With no walls or ceilings when you get off axis you really really hear the highs drop off... inside, not so obvious at all. Was kinda surprising when I did that... and it was on earth not on pavement of any sort, so kinda dead...

Oh, hold on...
Wait a second...
My name's not Andy!


_-_-bear
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Old 17th February 2011, 05:59 PM   #35
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Thanks, Andy, I mean Bear. That does make perfect sense with 3 panels, but having 4 makes that technique much more difficult, if not impossible, unfortunately. But, what angles did you end up with?
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Old 17th February 2011, 06:58 PM   #36
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Originally Posted by bolserst View Post
Here is the schematic for the 9300/9500. Quite the heat generators even at idle as I recall.
What a nicely drawn schematic, if I don't say so myself (I drew it!). Yes, the amp does run toasty even at idle, and even hotter when driven hard. However, the heatsink capacity is very good, and despite driving my 9500 very hard at times into Acoustats, it has never gone into thermal shutdown. And that's with a Hafler 9180 stacked on top of it, that I use for in-wall speakers in other rooms.

The design certainly represents the pinnacle of acheivement in amplifiers from both Halfer and Acoustat, as it uses lessons learned from previous products at both companies. For those of you who don't know, I started my audio career at Hafler in 1982, when the only products were the DH200 amplifier and DH-101 preamp. I moved over to Acoustat when Hafler bought the former. So you could say I know a good bit about Hafler products, too.
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Old 17th February 2011, 07:10 PM   #37
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Originally Posted by bear View Post
I used piano hinges, the length of the cells, with a thin MDF strip the length of the cells, but only as wide as the "dead" area on each edge to mount the piano hinge to... not perfectly ideal, but it did work nicely for my "space frame" Model IIIs... I did get a deal on very long piano hinges... and in the III the center panel is fixed rigid mount... it does get the cells closer together than the stock frame can.

IF you take the acoustats outside, you will likely find as I did just how beamy they are!
With no walls or ceilings when you get off axis you really really hear the highs drop off... inside, not so obvious at all. Was kinda surprising when I did that... and it was on earth not on pavement of any sort, so kinda dead...

Oh, hold on...
Wait a second...
My name's not Andy!


_-_-bear
Bear - I have NO problem with you providing answers to any of the questions directed at me. You probably have more experience with experimenting than I do, whereas my experience is more with Acoustat's product design, manufacturing, and after-sale service. I was directly responsible for the electromechanical design and final voicing for the entire Spectra line. Basically we kept Jim Strickland locked in a back room (not really) where he could dream up new and exciting ideas. It was my job to take those ideas and turn them into manufacturable, sellable products. Ahhhh...those were the glory days. Sure do miss 'em. My current job as a general manager of a precision sheetmetal shop just doesn't quite offer the same satisfaction. Oh well, many people never get to experience that kind of job satisfaction, so I count myself among the lucky ones who did.
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Old 17th February 2011, 07:32 PM   #38
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Originally Posted by Atom66 View Post
Hey Andy
I presently have Spectra 22s. I have been able to acquire the parts (extra panels and Spectra 44 /66 transformers) to build a Spectra 44 .Only problem I have is that the room that they have to go in does not have the height necessary to stack the panels as in the 44 and 66. What I was thinking of doing is placing the 4 panels side by side .Is this something you have tried? Should I be moving to a new house?
Thanks
Andrew
PS here is a link to some construction pictures of Acoustat panels in heavily reinforced steel /wood frames.

Canuck Audio Mart • View topic - The making of modified steel Acoustat's
Acoustat never made a 4-panel wide Spectra, even as an experiment. Sure, we dreamed of making a 'Spectra 8800', but the sales potential of such a behemoth was never great enough to consider it worthwhile. The number of Model 8's that were produced were very low - probably less than 50 pairs, maybe way less.

However, your idea is worth considering. Basically what you would be doing is adding two bass-only panels to the outer edge of your Spectra 22's. You'd want to use the transformers designed for the 44/66, with the bass tap set for a 44. However, unlike the 44/66, you would probably want to keep the same values for the high voltage coupling resistor, capacitor, and the sector resistors. This is because you would still have the same panel area devoted to full range and mids as your Spectra 22.

The height of the tall Acoustats probably did limit sales somewhat - if they had been a few inches shorter, Acoustat could have fit into more homes.

Good luck with this project - sounds like an interesting concept!
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Old 17th February 2011, 07:57 PM   #39
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I personally prefer the sound of the 4 panel wide arrays, but I got used to the 2+2 and can't live without the full height sound. My room doubles as a gym so single height Acoustats don't cover my ears while laying on the ground and standing, so I figure a 4+4 (I'm calling my project a Monitor 8 since I'm using Servo amps) gives me the best of both worlds, plus extra bass extension.
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Old 18th February 2011, 05:09 AM   #40
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Andy, no problem... you certainly have information that I just don't know anything about at all...

hella, I did not end up with an angle!

The whole idea was to have the "wings" be adjustable. Which they are. In practice I think I ended up using them at an angle that was similar to the factory frames. Although I did at times angle the inside cells a bit more than usual to get better imaging (you "see" mostly the center cell) without losing the bass and mids... but that was somewhat specific to my particular room set up (more than 2x longer than the width at 14' - but the listening position varied between ~ 10ft back to double that or more...).

There's not much to look at with them as I never really got the thing to a finished state, although it is/was functional. When you look at it is is 3 cells more or less floating in air, held from behind at some distance by a frame... with the spectra cells in place there are a lot of wires dripping out the bottom! I did put one set into nice silvery woven sleeves... better.

_-_-bear
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