John Curl's Blowtorch preamplifier part II

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I looked with many of my vinyls for hints. It was not easy nor conclusive but I didn’t find a lot below 50Hz for kick drums in rock and a bit lower in jazz.
Then I did some reading and it became obvious that there is a lot of sound processing going on (console equalization and miking manipulation) both for live and studio sound.
I asked some people and they told me that tuning of kick drum is done in a way that the sound fits in with the rest pieces of the drum set.
Only for consistency and convenience they tune it by ear to the pitch of E1 (low tuning 41. 2Hz) or A1(middle-low tuning 55Hz) of the four string bass.


George


Bass is usually cut well above 40hz on LP for playing time reasons if no other. Tuning bass or drums may or may not be tuned to E1 etc. But when they are and not cut by the mastering and pressing needs for LP, you do want to hear it that way... even if it isnt the majority. Now many (most) recording today are - even LP - with digital ADC etc. The bass is there on the masters and if used to make CD's will have the deeper bass intact.

There is a lot of talk about averages.... this is the wrong forum for that. The every day exceptions which rule my day. That bell curve -- the rest of us below the line.... even the 10%'ers at the bottom. High-End ought to get it right for all. And, leave the producers ideas/musicians to themselves.

I know this is about phono/LP here..... but many High-End systems can play both CD and LP. So, the recorded and playback needs of both in preamp/power amp/speaker design might include the abilities of both?


THx-RNMarsh
 
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By rock'n'roll and pop music habits, most of the time, kick drums are used to give more attack to the bass. So very low frequencies are removed and attack enhanced.
It is the reason why we used only one skin and a cushion to dump-it a lot.

It is only in case of a drum solo that i used all the available basses of the kick and bass tom-tom.
 
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There's just too much silliness on this thread - it's about time everyone knuckled down, and tried developing something worthwhile ... like this - https://www.youtube.com/watch?v=7Ydv9Ef-99I.
Somewhat reminiscent of the ancient days of outdoor concerts in the SF Bay area by Blue Cheer, which provoked loud noise complaints from the opposite side of the bay.
 
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Certainly not on many examples from the 60's through early 80's, very evident from the spectrum IME. Digital masters transferred to vinyl from after that time, perhaps.

Check out Decca classical recordings even.........

Maybe a low level recorded classical from Decca.... but R&R? I recall, loud and compressed but not deep, deep bass from LP. Maybe just my choices. But sounded to me like a cut was often chosen.

see..... Deciding How Long To Make Each Side Of Your Vinyl Record | The Masterdisk Record


http://www.recordingmag.com/resources/resourceDetail/114.html



THx-RNMarsh
 
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remember that if it went thru a tape recorder there really isn't much bass below 30 hz. Even today, Greg Orton's Mastering heads with extended low frequency only go to 17 hz at 15 ips, that would make it 34 hz for 30 ips. those are considered to be great numbers for tape.

Jack Endino put up a page with a selection of tape head responses, Response Curves of Analog Recorders , while I could quibble with some of the alignments, they are indicative of the general state of tape recorders.

Alan
 
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John,

Why not cancel the resonance feedback to a TT the same way you cancelled feedback with the Grateful Dead with the stacks at the back line of the stage, rather than using a HP filter? A transducer located in the right place on or about the TT?


THx-RNMarsh
 
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remember that if it went thru a tape recorder there really isn't much bass below 30 hz. Even today, Greg Orton's Mastering heads with extended low frequency only go to 17 hz at 15 ips, that would make it 34 hz for 30 ips. those are considered to be great numbers for tape.

Jack Endino put up a page with a selection of tape head responses, Response Curves of Analog Recorders , while I could quibble with some of the alignments, they are indicative of the general state of tape recorders.

Alan

I wonder what their GD is/was??
 
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John,

Why not cancel the resonance feedback to a TT the same way you cancelled feedback with the Grateful Dead with the stacks at the back line of the stage, rather than using a HP filter? A transducer located in the right place on or about the TT?


THx-RNMarsh

I just got an idea - I have this vibration sensor I used for speaker enclosures, maybe I should try it out on my record player!

Jan
 
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I just got an idea - I have this vibration sensor I used for speaker enclosures, maybe I should try it out on my record player!

Jan

I suspect you will change it by doing that . . .

There was a TED talk done by a guy from Google where they take an HD recording and amplify digitally any movement in the recording. Obviously you have to mount your camera on a tripod, but that may be a better - and easier - way to do it. The technique is so sensitive that it will convert vibration of things like a crisp packet - filmed through a window - in response to speach back into audio again.

You can upload your recordings to a server and they will process it and you can then download the result.

IIRC it was called light amplification. Theres a version that does color amplification as well. Yes, you face does pulse a brighter hue of red in response to your heartbeat.
 
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I just got an idea - I have this vibration sensor I used for speaker enclosures, maybe I should try it out on my record player!

As Brad said, “for further processing”.

Jan, you won’t find it easy fitting it and measuring correctly.

All you (wouldn’t) want to know on the subject:
http://www.mfpt.org/PDFs/MFPT%2059%20%20ACCELERATION%20MEASUREMENTS%20SESSION%204-19-05_comp.pdf

The area of interest is the LF area.
IMO, use the cartridge (velocity sensor) unfiltered output for minimum disruption of the mechanical system’s dynamics.

Second option, use a piezo disk between cartridge and head shell. Attach the cartridge to the disk and the disk to the headshell. The cartridge mass will act as the mass loading for the acceleration measurement.

Third option, a MEMs two or three axis accelerometer.
http://www.analog.com/media/en/news-marketing-collateral/product-selection-guide/MEMS_Inertial_Sensors_Selection_Tables.pdf
If it has enough sensitivity and low noise level at LF, this is the only option that will provide adequate discrimination btn vertical and lateral resonance modes data (and this is important if the signal is to be used for anything).

In any case I find the implementation too complex for the task of getting rid of the subsonic frequency components propagating past the cartridge output but this is just me.

If the output is to be used for servoing, remember that SONY had produced a TT with a fully servoed radial arm with piezo sensors , I don’t remember the model.



Obviously you read the answer, because you deleted it from your post.

It would be kind of you if you could provide some details of how you implemented this filter


Perfect high pass filters with no group delay are readily implemented via DSP.

Yes, I do not object to that.


What you don't show is waveform distortion when kick drum or any instrument produces a transient with low frequency content is played through a loudspeaker.

Esperado’s question triggered my curiosity as to how low kick drums go and I did a search for to answer this.
I haven’t captured playback distortion. This is another exercise. Thank you for the suggestion.:)

George
 
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