The Time/Phase Coherent Broadcast Masters Made by TLSG

[TLS Guy]

Now I have my new DAW up and running and the holiday season is past, I can show some of the gear here.

I have made YouTube videos from a concert recorded in my Brenell MK 6 and Revox A 700 reel to real recorders with dbx 1 code/encode. Also excerpts from a concert with the Chestnut Brass made with A Sansui PC-X1 with two portable Panasonic VHS recorders.

I have put a commentary on the videos so I won't go over it all again. However the recordings are phase coherent intensity difference stereo recordings. Almost all recordings available are spaced phase difference recordings which are awash with time aberrations. This has given rise to the issue that you can play fast ad loose with time/phase when designing speakers. The problem is that there are precious few time coherent recordings available. In my view coherent intensity difference stereo recordings give a much more realistic recording than phase difference stereo, especially if the speakers do not play fast and loose with time/phase.

First the analog production. This was the recording venue.

Now the microphone which is a Neumann SM 69 FET.

Now the recorders.

The Brenell MK6.

The Revox A 700 with dbx 157 at the very top.

So here are the analog recordings made on these machines.

I have also made a video of a concert recorded with a Sansui PC-X1 and two portable Panasonic VHS machines.

The two Panasonic recorders are on the left, top shelf. The Sansui PC-X1 is in the next shelf down on the right with its power supply adjacent to it on the right.

Here is a recording made with that equipment. The mixer used is in the pull out draw below the DAW screen.

This is the venue.

Please let me know what you think of these intensity difference stereo recordings.

I have more I can show you in later posts. I can show you what a half century old cartridge sounds like on a turntable even older. Also of interest to you may be commercial vintage reel to reel tapes, commercial reel to reel Dolby B encoded tapes, commercial dbx 2 encoded tapes, and dbx 2 encoded LPs.

If there is enough interest in this vintage technology I'm happy to demonstrate it via YouTube.

 

[shadyJ]

I am not sure what you mean by phase coherent recordings? A pair of mics would surely capture whatever is there in the venue, at least at the mic's position, both phase and amplitude. Post-processing might change some phase relationships, but I can't believe it would be a whole lot, at least if it wasn't extensive.

I did listen to your recording, and it sounds very nice, but how would the difference between your phase coherent recording and a more conventional recording be best compared? Through headphones, given that they are a minimum phase system with no acoustic interference? One-way speakers in an anechoic chamber? It seems to me that the damage done to phase relationships from normal room acoustics is quite a bit worse than what conventional loudspeakers do.

 

[TLS Guy]

Actually phase difference stereo and phase difference stereo have very different physics behind them.

The classic intensity stereo is the crossed cardiod where the mics are coincident, like this-:

This is the classic phase difference stereo mic technique.

The spaced mics can be cardiod or omni. I think the spaced omni is best as you get a more ambient recording. This was the technique used by Telarc in their classic recordings, and by Robert Fine in his Mercury Living presence recording. He often used three with a center mic and a three channel recorder.

The playback effect of the two techniques is very different. Allan Blumlein the inventor of stereo and miking was strongly in favor of the crossed intensity technique. I think he was absolutely correct.

The problem comes as usual with problematic speakers. I can assure you the intensity technique really sorts out the speakers. As the coherence of the speakers improves the precision and depth of the sound stage improves with it. So these type of recordings show allow the best full rangers to put their best foot forward.

The reason I got into recording was to make good live recordings that really helped sort out speaker designs. I can assure this they do. You will not hear the effect of these recordings on a speaker that makes a square wave look like a sine wave!

In my recordings I used either crossed figure if eight (classic Blumlein) or most often as these tapes were broadcast the M-S technique.

Shown above is a cardiod mic above a figure of 8 large capsule mic. My large dual capsule mic allowed the use of two identical capsules one above the other and allowed for the top capsule to be set to an omnidirectional pattern for maximal ambiance capture.

However the effect on playback was virtually identical and both techniques are classic intensity stereo.

There would be no phase shifts in the processing. Only editing was done, no dynamic range compression or any Eq what ever. These are true "purist" recordings. So these recordings will sound better as time shifts in speakers are progressively reduced. In my studio they put you right back at the original venue.

 

[TLS Guy]

I am not sure what you mean by phase coherent recordings? A pair of mics would surely capture whatever is there in the venue, at least at the mic's position, both phase and amplitude. Post-processing might change some phase relationships, but I can't believe it would be a whole lot, at least if it wasn't extensive.

I did listen to your recording, and it sounds very nice, but how would the difference between your phase coherent recording and a more conventional recording be best compared? Through headphones, given that they are a minimum phase system with no acoustic interference? One-way speakers in an anechoic chamber? It seems to me that the damage done to phase relationships from normal room acoustics is quite a bit worse than what conventional loudspeakers do.

I did not address your last point in the post below. The issue is that with intensity difference recordings using coincident mics, then the ambient field's time relationships to the direct field are correctly preserved. I think the best way of describing the result is that these recordings are open and ambient and still have superb imaging. With spaced phase difference omni mics you can get a nice ambient field but imaging is much poorer and the depth of the field is not as great. The other thing is that the bass is not as tight, which was the downfall of the Telarc recordings in my view.

 

[Irvrobinson]

The other thing is that the bass is not as tight, which was the downfall of the Telarc recordings in my view.

Many Telarc recordings have what seems like bigger than life bass because that's what Telarc wanted. Big bass. Especially in their Cincinnati Pops and Symphony recordings. The Cincinnati Music Hall (I've been there) supports bass better than any domestic hall I've been in, and for Telarc they used huge bass drums similar in size to those used on football fields by drum & bugle corps. Also, early Telarc recordings were made with Schoeps microphones, which I considered superior in realism to the blasé Sennheiser microphones that they switched to later on. I even wrote Jack Renner a letter suggesting that he go back to the Schoeps mics. He responded, thanking me for my opinion (ahem), and told me that he would think of me every time he used the Sennheiser mics. Uh huh.

I admit that I'm not generally a fan of spaced omni mics either. The Fine recordings never excited me. Sometimes I found the Telarc strategy worked well (almost anything recorded in Cincinnati), but their classic recordings of Mozart symphonies, for example, are pretty blah and lack life.

When I was serious about recording, ages ago, I used a Calrec Soundfield, which I considered at the time a remarkable little device. Recorded sounds were easily and often vividly reproduced well to the sides of the speakers. Alas, those recordings were made on an analog deck (a Crown CX822) with a Dolby unit, and while I have the tapes stashed somewhere I suspect they may no longer be playable, having been stored unprofessionally for almost 20 years. The equipment is long gone.

 

[TLS Guy]

Many Telarc recordings have what seems like bigger than life bass because that's what Telarc wanted. Big bass. Especially in their Cincinnati Pops and Symphony recordings. The Cincinnati Music Hall (I've been there) supports bass better than any domestic hall I've been in, and for Telarc they used huge bass drums similar in size to those used on football fields by drum & bugle corps. Also, early Telarc recordings were made with Schoeps microphones, which I considered superior in realism to the blasé Sennheiser microphones that they switched to later on. I even wrote Jack Renner a letter suggesting that he go back to the Schoeps mics. He responded, thanking me for my opinion (ahem), and told me that he would think of me every time he used the Sennheiser mics. Uh huh.

I admit that I'm not generally a fan of spaced omni mics either. The Fine recordings never excited me. Sometimes I found the Telarc strategy worked well (almost anything recorded in Cincinnati), but their classic recordings of Mozart symphonies, for example, are pretty blah and lack life.

When I was serious about recording, ages ago, I used a Calrec Soundfield, which I considered at the time a remarkable little device. Recorded sounds were easily and often vividly reproduced well to the sides of the speakers. Alas, those recordings were made on an analog deck (a Crown CX822) with a Dolby unit, and while I have the tapes stashed somewhere I suspect they may no longer be playable, having been stored unprofessionally for almost 20 years. The equipment is long gone.

I hoped you would see this post and respond. I have been hoping to generate discussion with this post.

The Calrec was a wonderful microphone, sadly beyond my budget. The Neumann SM 69 FET stretched it to the limit as it was. So I always regarded my SM 69 FET as a poor man's Calrec. Although I can't remember if the Calrec was actually around when I bought my Neumann.

Unfortunately the divergent demands of the pop world and the classical world have led to the ubiquitous use of phase difference stereo. This is the way engineers are trained.

The problem with intensity difference stereo is that you can not use spot mics with abandon. You get a terrible result. You can use spot mics sparingly. You have to just crack them open and just have them live when required. I used to follow a conductors score.

The other issue that a recording with a bunch of spot mics, means the engineer is in charge of the recorded balance and NOT the conductor. I regard that as a real issue. I tried to make my recordings as faithful as possible to the original performance.

Now to change gear. Do you remember the brand of tape you used for those Calrec recordings? It was the earlier Ampex master tapes using a whale oil based binder for the magnetic coating. This fails over time. However I do have a baking system that will usually restore the tapes to give one good play for digital archiving. I also have a stash of Ampex Grand Master pancakes after they stopped using the whale oil based binder. So I would also be able to give you a clean analog dub as well.

I would guess the Dolby unit was a Dolby A. I do have Dolby A decoders, but have never used them! I'm yet to be sent a Dolby A tape for archiving. So if you find those tapes I would be happy to see if they could be restored and archived.

What did you make of those recordings I put up by the way?

 

[Irvrobinson]

I hoped you would see this post and respond. I have been hoping to generate discussion with this post.

The Calrec was a wonderful microphone, sadly beyond my budget. The Neumann SM 69 FET stretched it to the limit as it was. So I always regarded my SM 69 FET as a poor man's Calrec. Although I can't remember if the Calrec was actually around when I bought my Neumann.

Unfortunately the divergent demands of the pop world and the classical world have led to the ubiquitous use of phase difference stereo. This is the way engineers are trained.

The problem with intensity difference stereo is that you can not use spot mics with abandon. You get a terrible result. You can use spot mics sparingly. You have to just crack them open and just have them live when required. I used to follow a conductors score.

The other issue that a recording with a bunch of spot mics, means the engineer is in charge of the recorded balance and NOT the conductor. I regard that as a real issue. I tried to make my recordings as faithful as possible to the original performance.

Now to change gear. Do you remember the brand of tape you used for those Calrec recordings? It was the earlier Ampex master tapes using a whale oil based binder for the magnetic coating. This fails over time. However I do have a baking system that will usually restore the tapes to give one good play for digital archiving. I also have a stash of Ampex Grand Master pancakes after they stopped using the whale oil based binder. So I would also be able to give you a clean analog dub as well.

I would guess the Dolby unit was a Dolby A. I do have Dolby A decoders, but have never used them! I'm yet to be sent a Dolby A tape for archiving. So if you find those tapes I would be happy to see if they could be restored and archived.

What did you make of those recordings I put up by the way?

Unfortunately, Mark, I won't be in the same physical location as my music system for a few weeks, so I can't listen to your recordings in a venue that will do them justice, but I will try tonight on my apartment system if I get a chance. I will also try to remember to listen more formally when I get back to my primary residence.

I completely agree with you that most commercial recordings, even those for classical music, are essentially crap. The older I get, and the better my music system gets, the less tolerant I've become of crappy recordings.

For example, a few months ago I ordered a box set of Itzhak Perlman recordings on DG. The price was irresistible, and of course Perlman is awesome. And DG recordings are often very good, so I was excited about the purchase. (I especially admire DG's series with The Orpheus Chamber Orchestra.) Much to my disgust, the Perlman recordings are crap. Perlman's violin sounds like it's 6 feet long and has a 500 watt PA system amplifying it. The orchestras were obviously spot-mic'd and the mixes manipulated. The playing was awesome, but I can't listen to the CDs. There's no relationship to what Perlman or the orchestras would sound like in concert. Frankly, I'm surprised Perlman himself tolerates that nonsense.

I always used Ampex 456 tape. It was a Dolby A unit I got (well) used for about $200 from a local studio that went belly-up. I actually sold it some years ago for more than I paid it for about ten years earlier. I recorded at 7.5 IPS on the Crown because I thought the bass response was better than when I tried 15 IPS.

The recordings themselves are simply amateurs playing on individual instruments in my home during that period, so there's nothing especially valuable about them, except perhaps sentimental value. The Calrec mic was amazing though. In one recording I distinctly remember, of my ex-wife playing her piano, my son brushed against a wall about six feet to the side of the piano, making a slight noise while I was recording. I actually didn't think it would be audible, so I just gave him a stern look and stayed the course. When the recording was played back on my then-current ADS L1530 speakers, we got the illusion of the noise from the wall brushing about six feet to the left of the left speaker. It was quite remarkable.

Thank you for offering to restore the tapes, but I really don't think they're worth your effort, or even mine to ship them.

 

[Swerd]

Although I know nothing about sound recording or microphones, I'm definitely interested in this subject. What little I know of the subject of time and/or phase "smearing" in recordings, I've learned from reading the liner notes of older Grateful Dead recordings. It seems some older recordings, taped live with microphone feeds, suffered from "time distortion" due to careless microphone location. Some one associated with them eventually learned how to correct for that and produced rather good sounding recordings which preserved the cues for locating individual musicians. I'll have to search for those notes to see what they actually said.

I haven't yet properly listened to your recordings, primarily because I don't have a ready method for doing it. (I readily admit I'm a dinosaur in that regard.) It will require me to borrow my wife's laptop and hook it up to my sound system. I believe I have a RCA-3.5 mm analog cord already in my receiver that my son installed. My only question is whether the laptop's rudimentary sound card will do justice. I'll do that tomorrow for certain and get back with my impressions.

My Dennis Murphy designed Salk speakers have crossovers designed to achieve LR 4th order acoustic roll-off slopes when combined with the drivers. I don't know if they have a 4th order electronic network, I suspect not. According to Dennis, they are phase aligned but not time aligned. At the crossover frequency, roughly 2500 Hz, the woofers and tweeter are 360° out-of-phase with each other, and therefore time mis-aligned by 1 cycle. At 2500 Hz, 1 cycle would be 0.4 milli seconds. I wonder I'll notice any difference.

I'm getting over what might have been the 1½ day flu. I am taking immune supressing drugs (low dose prednisone 7.5 mg/day plus low dose methotrexate 25 mg/week) to treat my autoimmune eye inflammation. It's very much the same regimen used to treat rheumatoid arthritis. I did get a flu vaccine shot last September. So, with this year's partially effective vaccine and the partial immune suppressing drugs, I had the partial flu. I had a brief encounter with body aches, chills, and general fatigue for about a day and a half. But I had no fever, sore throat, sinus involvement or cough. Saturday I felt fine; Sunday & Monday I felt I was coming down with the flu; and today I feel normal. I hope that lasts.

 

[TLS Guy]

Although I know nothing about sound recording or microphones, I'm definitely interested in this subject. What little I know of the subject of time and/or phase "smearing" in recordings, I've learned from reading the liner notes of older Grateful Dead recordings. It seems some older recordings, taped live with microphone feeds, suffered from "time distortion" due to careless microphone location. Some one associated with them eventually learned how to correct for that and produced rather good sounding recordings which preserved the cues for locating individual musicians. I'll have to search for those notes to see what they actually said.

I haven't yet properly listened to your recordings, primarily because I don't have a ready method for doing it. (I readily admit I'm a dinosaur in that regard.) It will require me to borrow my wife's laptop and hook it up to my sound system. I believe I have a RCA-3.5 mm analog cord already in my receiver that my son installed. My only question is whether the laptop's rudimentary sound card will do justice. I'll do that tomorrow for certain and get back with my impressions.

My Dennis Murphy designed Salk speakers have crossovers designed to achieve LR 4th order acoustic roll-off slopes when combined with the drivers. I don't know if they have a 4th order electronic network, I suspect not. According to Dennis, they are phase aligned but not time aligned. At the crossover frequency, roughly 2500 Hz, the woofers and tweeter are 360° out-of-phase with each other, and therefore time mis-aligned by 1 cycle. At 2500 Hz, 1 cycle would be 0.4 milli seconds. I wonder I'll notice any difference.

I'm getting over what might have been the 1½ day flu. I am taking immune supressing drugs (low dose prednisone 7.5 mg/day plus low dose methotrexate 25 mg/week) to treat my autoimmune eye inflammation. It's very much the same regimen used to treat rheumatoid arthritis. I did get a flu vaccine shot last September. So, with this year's partially effective vaccine and the partial immune suppressing drugs, I had the partial flu. I had a brief encounter with body aches, chills, and general fatigue for about a day and a half. But I had no fever, sore throat, sinus involvement or cough. Saturday I felt fine; Sunday & Monday I felt I was coming down with the flu; and today I feel normal. I hope that lasts.

Sorry to learn you are "under the weather." Hopefully you will be better soon.

I should, I suppose, have realized there would be some who can not get YouTube up on their big screens.

Your cable solution will not allow you to look at the video component and it not the highest quality audio connection.

The easiest way for you do do it would be to purchase a Chromecast unit. It will be about the best value for $35 you will ever spend at Best Buy.

Set up is easy.

You can cast from an iPhone, Andorid phone, iPad, tablet or laptop via Google Chrome.

This is the major route to stream from two if my four rigs.

Other ways to stream are HTPCs and so called Smart Apps, like those in TVs, and receivers are now starting to have them

Streaming is so much better than conventional TV. 90% or more of what we watch is now streamed. Cable and satellite has lots of programming with nothing to watch. Streaming gives you access to what you want. Quality is now excellent. I find by far the easiest is to use an HTPC. I think it is part of the home entertainment scene to be able to open a web browser on a TV screen.

Sky TV one of the UKs TV networks and supplier of satellite service and going to shut down their satellite service. They are the UKs largest satellite service. The are going to total Internet distribution.

 

[yepimonfire]

Sorry to learn you are "under the weather." Hopefully you will be better soon.

I should, I suppose, have realized there would be some who can not get YouTube up on their big screens.

Your cable solution will not allow you to look at the video component and it not the highest quality audio connection.

The easiest way for you do do it would be to purchase a Chromecast unit. It will be about the best value for $35 you will ever spend at Best Buy.

Set up is easy.

You can cast from an iPhone, Andorid phone, iPad, tablet or laptop via Google Chrome.

This is the major route to stream from two if my four rigs.

Other ways to stream are HTPCs and so called Smart Apps, like those in TVs, and receivers are now starting to have them

Streaming is so much better than conventional TV. 90% or more of what we watch is now streamed. Cable and satellite has lots of programming with nothing to watch. Streaming gives you access to what you want. Quality is now excellent. I find by far the easiest is to use an HTPC. I think it is part of the home entertainment scene to be able to open a web browser on a TV screen.

Sky TV one of the UKs TV networks and supplier of satellite service and going to shut down their satellite service. They are the UKs largest satellite service. The are going to total Internet distribution.

I definitely agree with you on streaming! Even amazon instant video, which IMO is subjectively the worst quality video and audio wise, sounds and looks better than cable. VUDU is nearly as high quality as blu-ray, I heat no compression artifacts in the audio, and the 4k video offers a noticeable improvement over 1080p blu-ray.

I'm confused what you're getting at in your OP, are you saying a recording that creates a stereo imaging only based on level differences instead of temporal differences sounds better? Also, I'm fairly certain most pop music is entirely pan pot stereo with close miced instruments, I find both intensity and time of arrival differences are necessary for a convincing stereo image, since this is how sounds arrive in real life.

The speakers I currently own appear to be time aligned based on the step response measurements. I don't really know whether or not perfect time alignment as seen in a square wave test or "perfect triangle" step response is necessary for a coherent sound stage, but I do know that even a 1ms delay introduced via the AVR distance settings between the LR is easily audible, giving way to a wrecked sound stage that lacks coherence.

Personally I think two channel stereo is flawed anyways though.

Sent from my LM-X210(G) using Tapatalk

 

[TLS Guy]

I definitely agree with you on streaming! Even amazon instant video, which IMO is subjectively the worst quality video and audio wise, sounds and looks better than cable. VUDU is nearly as high quality as blu-ray, I heat no compression artifacts in the audio, and the 4k video offers a noticeable improvement over 1080p blu-ray.

I'm confused what you're getting at in your OP, are you saying a recording that creates a stereo imaging only based on level differences instead of temporal differences sounds better? Also, I'm fairly certain most pop music is entirely pan pot stereo with close miced instruments, I find both intensity and time of arrival differences are necessary for a convincing stereo image, since this is how sounds arrive in real life.

The speakers I currently own appear to be time aligned based on the step response measurements. I don't really know whether or not perfect time alignment as seen in a square wave test or "perfect triangle" step response is necessary for a coherent sound stage, but I do know that even a 1ms delay introduced via the AVR distance settings between the LR is easily audible, giving way to a wrecked sound stage that lacks coherence.

Personally I think two channel stereo is flawed anyways though.

Sent from my LM-X210(G) using Tapatalk

I already addressed the fact that intensity difference stereo will not work for pop music. I am saying the Intensity difference stereo is superior to phase difference stereo, because timing issues are at least solved.

The problem with stereo it that the largely out of phase ambient field is reproduced with the front sound stage. The algorithms like Dolby PL 2x do sort this out to some degree, and sort it out actually quite well in my intensity difference recordings.

It is obviously true that you can not create a realistic ambient field with two speakers. The wonder is that it works as well as it does.

 

[Swerd]

Sorry to learn you are "under the weather." Hopefully you will be better soon.

Thanks. Yesterday and today (so far) I've felt pretty good. Whatever I had, it seems to have been short lived.

The easiest way for you do do it would be to purchase a Chromecast unit. It will be about the best value for $35 you will ever spend at Best Buy.

Thanks for the tip. My wife's laptop is a Google Chromebook, about 1½ years old. Perhaps it already has the right software. If not, the Chromecast unit you suggest is inexpensive and has your endorsement. That's should be easy to implement.

My Panasonic Blu-Ray player is smart and I use it to download movies and internet material via wifi. Do you know if the added Chromecast unit will cooperate with that?[/QUOTE]

 

[TLS Guy]

Thanks. Yesterday and today (so far) I've felt pretty good. Whatever I had, it seems to have been short lived.
Thanks for the tip. My wife's laptop is a Google Chromebook, about 1½ years old. Perhaps it already has the right software. If not, the Chromecast unit you suggest is inexpensive and has your endorsement. That's should be easy to implement.

My Panasonic Blu-Ray player is smart and I use it to download movies and internet material via wifi. Do you know if the added Chromecast unit will cooperate with that?

[/QUOTE]

First Panasonic devices no longer support YouTube.

Chromecast is clever. It plugs into the HDMI port of your receiver. I doubt your receiver has ARC, so you must go through your receiver to watch and here my videas and others. The Chromecast unit also needs a source of AC power.

Now you have to set up the Chromecast unit to mate with your router. It is easy.

Now you can only Chromecast from a Chrome browser. This is the Chromecast icon.

Now not all streams support Chromecast, but most do and more all the time.

So you get your YouTube video up in Chrome and press the Chromecast icon. It will then ask which device you want to connect to. You click the one you want. If you only have one there will only be one displayed.

Now this is the clever part. Chromecast does not triangulate. In other words once you connect then the program streams from your router straight to the Chroemcast unit, and your portable unit is JUST the controller. So quality is excellent. You can use your mobile device as normal while casting.

Since your wife's device is a Google device I'm sure it will work.

If you have a laptop and I'm sure you do, then it will cast from a stream open in Chrome. You must use the Chrome browser.

When you are done you press the icon and then disconnect. It is really simple. Even the senile geriatric set like you and I get the hang of it right away.

By the way as long as I'm able to use my new DAW I know I do not need a dementia check. That unit is quite a challenge. Once I start getting that complex screen at sixes and sevens I know it is time for the neuro psychologist and the head scanning department.

There is lots of evidence that if you keep challenging yourself with complex task after you retire, the onset of dementia if you are headed that way is greatly slowed if not prevented.

So I have purposely kept my life complicated since I retired, especially from a tech point of view and mechanical work on the antique machinery.

 

[yepimonfire]

I already addressed the fact that intensity difference stereo will not work for pop music. I am saying the Intensity difference stereo is superior to phase difference stereo, because timing issues are at least solved.

The problem with stereo it that the largely out of phase ambient field is reproduced with the front sound stage. The algorithms like Dolby PL 2x do sort this out to some degree, and sort it out actually quite well in my intensity difference recordings.

It is obviously true that you can not create a realistic ambient field with two speakers. The wonder is that it works as well as it does.

Which is why I always use DSU. How would plii/DSU work better with intensity difference stereo vs phase difference? Algorithms such as those largely derive the surrounds and heights almost entirely based on phase differences.

Perhaps I'm misunderstanding how intensity difference recordings work.

Sent from my LM-X210(G) using Tapatalk

 

[TLS Guy]

Which is why I always use DSU. How would plii/DSU work better with intensity difference stereo vs phase difference? Algorithms such as those largely derive the surrounds and heights almost entirely based on phase differences.

Perhaps I'm misunderstanding how intensity difference recordings work.

Sent from my LM-X210(G) using Tapatalk

As I explained the reason the algorithms work better is because the in phase and out of phase information is gathered from the same place for left and right microphones, and not eight or more feet apart.

Have you played my recordings? If you do you will see what I mean. The recording from the ambient space of the church is particularly revealing of what I am saying, and a good demonstration.

 

[Pogre]

Most of that is over my head, but that's one hell of a venue!

 

[Irvrobinson]

I finally found some time to listen to these recordings, albeit on my computer-based system in my apartment in SoCal. This system is pretty good for a computer-oriented one, and I normally use it for watching movies and television I stream on the computer. It consists of a 27" iMac, which drives a pair of Audioengine 5+ powered monitors sitting on my desktop about four inches to each side of the iMac. The desk sits close to (but not touching) a back wall, and the back of the speakers are about three inches from the wall. An SVS SB1000 sits on the floor to the right side of the desk, and I when set up the system recently I spent about an hour with OmniMic adjusting the crossover, volume, and phase of the sub to best match with the Audioengine mains.

All of that said, the sound of this system is nothing like the quality of my primary home music system. If my primary system is a 9.0+ on a scale of 10.0, this computer-based system is a 5.0. Maybe. The Audioengines are okay for what they are, little powered monitors, but sitting on a large wooden desktop, close to the back wall, does them no favors. However, caveats aside, I did get a feel for the recordings.

In the first recording, even this compromised system was able to throw a 3D image of the chorus. The image was above, to the sides, to the rear, and occasionally out front of the mains, as when the drums came in at about the 14:20 mark. On this recording I found myself often leaning in towards the monitor, as if to try to lean into the venue to hear more detail. And I cursed the guy coughing to the left side sometimes, as he was distracting, but even his coughing demonstrated the 3D effect of the recording, as his coughs were audibly "closer" in a spatial sense than the orchestra and the chorus. I also found myself smiling a bit now and then with this recording, and I'm not much of a smiler.

I actually preferred the second recording. The horns are quite realistic, even on my highly compromised system. I listened to the whole thing twice. The most telling part, however, were the breaks in the recording, where you spliced together multiple recordings, and the background noises of the room went away. A vivid 3D image of the hall sound suddenly collapsed, revealing an image you didn't really notice was there until it was gone. That made me smile the most.

I'm anxious to play these recordings when I get back to my primary system.

Nicely done.

 

[TLS Guy]

I finally found some time to listen to these recordings, albeit on my computer-based system in my apartment in SoCal. This system is pretty good for a computer-oriented one, and I normally use it for watching movies and television I stream on the computer. It consists of a 27" iMac, which drives a pair of Audioengine 5+ powered monitors sitting on my desktop about four inches to each side of the iMac. The desk sits close to (but not touching) a back wall, and the back of the speakers are about three inches from the wall. An SVS SB1000 sits on the floor to the right side of the desk, and I when set up the system recently I spent about an hour with OmniMic adjusting the crossover, volume, and phase of the sub to best match with the Audioengine mains.

All of that said, the sound of this system is nothing like the quality of my primary home music system. If my primary system is a 9.0+ on a scale of 10.0, this computer-based system is a 5.0. Maybe. The Audioengines are okay for what they are, little powered monitors, but sitting on a large wooden desktop, close the back wall, does them no favors. However, caveats aside, I did get a feel for the recordings.

In the first recording, even this compromised system was able to throw a 3D image of the chorus. The image was above, to the sides, to the rear, and occasionally out front of the mains, as when the drums came in at about the 14:20 mark. On this recording I found myself often leaning in towards the monitor, as if to try to lean in the venue to hear more detail. And I cursed the guy coughing to the left side sometimes, as he was distracting, but even his coughing demonstrated the 3D effect of the recording, as his coughs were audibly "closer" in a spatial sense than the orchestra and the chorus. I also found myself smiling a bit now and then with this recording, and I'm not much of a smiler.

I actually preferred the second recording more. The horns are quite realistic, even on my highly compromised system. I listened to the whole thing twice. The most telling part, however, were the breaks in the recording, where you spliced together multiple recordings, and the background noises of the room went away. A vivid 3D image of the hall sound suddenly collapsed, revealing an image you didn't really notice was there until it was gone. That made me smile the most.

I'm anxious to play these recordings when I get back to my primary system.

Nicely done.

Thank you for that kind review. I await with interest your take on it on your prime rig.

I have a lot of those recordings and some good stuff. I suppose I should get around to putting the best of it up on YouTube.

People used to look forward to my broadcasts, and some went out all over ND, not just the UND public radio station. You have made recordings so you know how much work it is!

I did note that on the Crown you felt the bass was better at 7.5 ips. The reason is actually that there is less HF. When you do the bias and Eq at any tape speed below 15 ips, you have to do it at -20db That is because of tape saturation. This coupled with the fact that most machines rolled off around or above 30 Hz. So it takes a tape running at 15 ips to be flat to 20 KHz at full tape modulation. Slower speeds will not make it no matter what the tape or machine.

Only Studer/Revox heads could make out to flat at 20 Hz. Even so the machine had to be obsessionally set up to make it to 20 Hz to 20 KHz. You can see those machines made it to 20 KHz from the spectrum meter. Incidentally I left the monitor screen showing on the tape so people can see the energy spectrum of music by frequency band. You can easily see on those recordings the big power demands are well above sub range. In fact in the range of a sub the power requirements are very modes, you can see that easily from the screen.

 

[Irvrobinson]

I did note that on the Crown you felt the bass was better at 7.5 ips. The reason is actually that there is less HF. When you do the bias and Eq at any tape speed below 15 ips, you have to do it at -20db That is because of tape saturation. This coupled with the fact that most machines rolled off around or above 30 Hz. So it takes a tape running at 15 ips to be flat to 20 KHz at full tape modulation. Slower speeds will not make it no matter what the tape or machine.

I acquired the Crown from an estate sale, very lightly used by the original owner. It was a trophy piece, apparently, and I had it refurbished to, supposedly, better than new specs by an ex-Crown factory tech. He sent along measurement print-outs that he did showing nearly flat response from 20-20KHz at both speeds, but in my experimentation I still thought a recorded piano (which was my primary subject) sounded better at 7.5 IPS than 15 IPS. The Crown was even optimized using my favorite Ampex 456 tape. With the Dolby unit there was no difference in noise, and I think my speakers at the time (ADS L1530s and M15s) were probably a little rolled off above 15KHz anyway. Perhaps the perception of less bass was an interaction effect between the electronics and the Calrec. Or not.

You're right about recording being a lot of work, especially with big, clunky equipment like the CX822. It was huge and heavy. And then there's cables, a mike stand, power cords, you know. And I didn't have a studio, just my living room, so I was setting up and tearing down anytime I wanted to record. Positioning the Calrec was also a finicky process. You couldn't be too close or too far from the instruments or the singer, and that took (for me at least) some trial and error. I remember lots of errors. It didn't work out very often. And the investment was pretty big too. Just the tape was expensive to me at the time, what with raising kids and such. I got lucky with the Calrec, just by chance being introduced to an older guy (probably about the same age I am now) who did recordings at his church, and found the Calrec didn't work out. I was excited about it, and asked about twenty questions, having read about it but never actually seeing one before, and he offered it to me for an embarrassingly low price. He was impressed that I even knew what it was, and I think he was wealthy enough that the Calrec was just another toy to him. Like I said, I lucked out.

Anyway, you should post more of your recordings. Or perhaps burn some CDs for fans. I'd buy them.

 

[Pogre]

I'm listening to the video right now. The introduction has just ended.