IMF Ambisonic Decoder

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A/V SQuad

Well-known Member
Joined
Oct 4, 2004
Messages
114
Location
Philly
What's a used unit worth these days? Saw one for sale, seemed reasonable.

Also, what's it good for if you don't have ambisonic recordings? Smoothing out quad or stereo? Does it add to decoded SQ/QS? IMF was a great company, at least for speakers, are the electronics on this unit quiet and high caliber?

Wasn't really in the market for this unit, but it's one of those things that's hard to pass up when you see one.
 
I am not likely to use it extensively for listening to classical stuff on Nimbus and similar labels that record with a proper ambisonic mic, so I guess I am most interested to know if the Super Stereo feature will enhance all recordings, or just clutter my signal chain. I suppose the price is cheap enough to find out.

Also, I wonder what the deal is with this decoder playing recordings made with a regular stereo mic pair, cardioid pattern, off axis 90 degrees. This is the setup that is discussed as preserving phase and echo information, and isn't supposed to require a decoder. I guess the Alan Parsons Stereotomy is the best example of this. Does an Ambisonic decoder enhance the playback of this type of signal further?

I did a lot of reading after my 1st post, seems as if the Ambisonic community is even more emphatic than the regular quaddies. Or I guess they might refer to quaddies as 4 pot mono enthusiasts.

Note: I'm not trying to start another flame war here. I haven't even heard Ambisonics. Yet.
 
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I never bothered with ambisonics simply because of the lack of compelling software. There are perhaps four titles I found intriguing last time I searched for material, with three of them being a stretch. Only Stereotomy got me excited. One title is not enough for me to dedicate rack space to a decoder. Thank god for DTS conversions! ;)
 
Hey, I never followed up on this thread. I did buy the decoder for $60, and got it hooked up at the same time as my new QSD-2 (which cost a good deal more). I've got to say that I am listening to most everything on both the QS decoding and Ambisonic Super Stereo enabled at the same time. The IMF does seem to improve the quad image regardless of where you're sitting, and make my speakers sound less localized. The effect is more on the subtle side than dramatic, but definitely a good pick up for my system.

I did get the King Sunny and Cowboy Junkies CD's which are UHJ encoded. Again, more subtle than matrix quad but pleasing.









Cai Campbell said:
I never bothered with ambisonics simply because of the lack of compelling software. There are perhaps four titles I found intriguing last time I searched for material, with three of them being a stretch. Only Stereotomy got me excited. One title is not enough for me to dedicate rack space to a decoder. Thank god for DTS conversions! ;)
 
A/V SQuad said:
Hey, I never followed up on this thread. I did buy the decoder for $60, and got it hooked up at the same time as my new QSD-2 (which cost a good deal more). I've got to say that I am listening to most everything on both the QS decoding and Ambisonic Super Stereo enabled at the same time. The IMF does seem to improve the quad image regardless of where you're sitting, and make my speakers sound less localized. The effect is more on the subtle side than dramatic, but definitely a good pick up for my system.

I did get the King Sunny and Cowboy Junkies CD's which are UHJ encoded. Again, more subtle than matrix quad but pleasing.

This does not surprise me -ambisonics has a habit of improving most surround recordings; pity really it's dead in the water. Like most British inventions sadly.
Oh well, I enjoy it. I'm currently working on some ambisoinc mixes (from stereo) of a few prog-rock albums; will report back on the results soon.
Best
Scott
 
Just acquired an IMF Ambisonic Decoder type D20B and would love a copy of the user manual or service manual if anyone has them.

Thanks,

Mike.
 
I have been playing
stereo first into the surround Master TSS stereo enhancer
then into The IMF UHJ decode
It seems to make stereo into UHJ some effects are very good
I can switch from the UHJ into a QSD1 QS decode and get a very
different effect 2 very interesting ways of playing stereo in Surround
 
I have been playing
stereo first into the surround Master TSS stereo enhancer
then into The IMF UHJ decode
It seems to make stereo into UHJ some effects are very good
I can switch from the UHJ into a QSD1 QS decode and get a very
different effect 2 very interesting ways of playing stereo in Surround

Obviously, you can play stereo sources through any two-channel decoder. And this can produce weird and interesting effects.

However, listeners who do not want these should select Super Stereo (not UHJ) on their Ambisonic decoder. Also, instead of the "TSS stereo enhancer" they can simply use the Stereo Width control; this allows the stereo image to be compressed to mono-like or expanded into a horseshoe around the listener.

Regards,
Martin
 
What I mean is that playing through the TSS first it
gives a surround sound to stereo
as though it was a UHJ recording
The display on the scope gives a ball of sound like UHJ
and playing types of music gives a very good hall sound
speech has a ambiance of UHJ
I have tried the Stereo wide on the UHJ but it does
not give the circle of surround as well
 
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