John Curl's Blowtorch preamplifier part II

Status
Not open for further replies.
Member
Joined 2002
Paid Member
PMA's organ file, only the 1st second
 

Attachments

  • PMA 1sa.JPG
    PMA 1sa.JPG
    109.2 KB · Views: 220
  • PMA 1sb.JPG
    PMA 1sb.JPG
    102 KB · Views: 221
I get my house back Friday, but for the last three years I have been relegated to a very nice but small office 8x10. I use my MET 7's (4-5") as TV speakers and I just started using the HDMI based audio output and am relatively surprised at how good the network streaming has gotten. I never use tone controls but for one movie I thought I would like to turn the bass down a little (not really but humor me).

Ok i will ...:)


Now Bass or mud , mud most want to turn down , bass , Not , actually its the opposite, clean , articulate powerful bass most want to turn up not down ..


Mud , not so ..... :)
 
Pavel,
I brought up the organ for what I thought were obvious reasons. But only you and George seemed to get it.

As George had covered the basics of the envelope of a note. I think it should be clear that just looking at a single time sample spectrum does not contain enough information.

Where this is headed is that in the original synthesis what was addressed was pitch and amplitude. Newer techniques used FM. Synthesis. Looking at the spectrums you showed had base spreading hinting at FM.

You also mention one fault of a tuned port in that it causes a sharper roll off. Another issue is that the resonance lengthens the sustain period.

Looking at note synthesis and how it fails or succeeds points to important issues in perception.

ES

see Griesinger ---- later, gotta go
 
Member
Joined 2002
Paid Member
Yes Ed
Momentary spectrum snapshots can’t tell all but here are some spectrums of real organs playing notes.
http://www.aplu.ch/overtone/hauser/hauser.pdf

http://kraemer-bechen.de/FFT_Facharbeit.pdf

http://www.physik.uni-wuerzburg.de/fileadmin/11010700/Didaktik/Zulassungsarbeiten/Physik_und_Musik_-_Koch_-_ohne_Kap._2.3.pdf

For those who are still visiting technical libraries for to read the old printed format (books), and who are interested in real instrument’s dynamic spectrum formation, here is the groundwork (can’t find it on the internet):

https://openlibrary.org/works/OL16345945W/Die_Klangspektren_der_Musikinstrumente



Mooly, those two piano “D” recordings:
1 They have totally different dynamics.
2 Are they real pianos or is it sampling? (there is total absense of ambient background noise at the fade-out of the piano tone)

George
 

Attachments

  • Mooly 1+2.JPG
    Mooly 1+2.JPG
    115.2 KB · Views: 209
PMA's organ file full length

I see fan noise in there! (Not blower noise the two are different.) What is interesting is the low frequency amplitude modulation.

If you want to rotate it a bit more the time zero vs frequency view will show more of the attack.

In a reverberant room it times some time for the energy to build to fill the room. This cab be a few seconds in large rooms. As most large rooms are not simple shapes you often see the combination of multiple attacks from each segment.

I like your presentation.
 
Member
Joined 2002
Paid Member
Reading some old books on music theory these days, I found an information that I think illuminates a technical dark point:

Technical literature says that the arm-cart resonance frequency should be not lower than 8Hz and not higher than 12Hz.

Re 12Hz limit:
Music theory says that at around 16Hz we start to develop the sense of tone.

Re 8Hz limit:
Music theory says that:
3Hz to 5Hz is the optimum modulation frequency range for tremolo effect (amplitude modulation).
5Hz to 7Hz is the optimum modulation frequency range for vibrato effect (frequency modulation).

George
 
Last edited:
I use Met 7's for my Comcast TV link. It works very well for me. I suspect that Dick Sequerra feels that good transient response is more important than super accurate frequency response. They work for me! One of the best bargains in quality audio, I believe. Dick has stopped making them, I am told.
The only thing that I can tell is not 'hi fi' is that they do 'forgive' the sound quality, rather than let the irritation through.
Compared to my WATT 1's with sub-woofer, the WATTS are slightly clearer and more extended in the highs. This is good for hi fi evaluation, but lousy for TV.
When I get my new Wilson speakers, I will have yet another quality pair of speakers to compare with, in a few weeks.
 
Not so Uncle Scott and i'm the same with Uncle John , told him when the Parasound fell short...

I've become quite attached to WXYC's difficult music hour every Sunday 2-3PM.

I could cry foul that quoting an audio reviewer is an appeal to authority, but that would be too generous. I'm sure a thorough search could find the entire range of opinions of the same item. Maybe I should listen to 6moons reviews of Peter Belt's and Geoff Kait's offerings.
 
Last edited:
Member
Joined 2002
Paid Member
Somehow a few cases followed me home.
Last project was near where they make bourbon. Same problem.

Somebody has cursed (or blessed) you :D



In a reverberant room it times some time for the energy to build to fill the room

So does the energy to build-up in the arm-cart system due to very strong groove modulation, for to initiate with a delay the generation of higher signal harmonics at the cartridge output. In my set-up this delay is somewhere btn 70-120ms.

George
 
I've become quite attached to WXYC's difficult music hour every Sunday 2-3PM.

I could cry foul that quoting an audio reviewer is an appeal to authority, but that would be too generous. I'm sure a thorough search could find the entire range of opinions of the same item. Maybe I should listen to 6moons reviews of Peter Belt's and Geoff Kait's offerings.

Humour me ... :)


I'm sure my desktops are not any better , but with sub , sounds good because there's no expectations ...

Funny how that works .....
 
Last edited:
Humour me ... :)


I'm sure my desktops are not any better , but with sub , sounds good because there's no expectations ...

Funny how that works .....

Expectations are dangerous. I aviod them at all costs.

EDIT - Peace, you can't possibly be that interested in my enjoyment of 5" drivers as I could care less about your 15" drivers.
 
Last edited:
Nope , all frequencies require percussive energy, you cant get "realistic" from a single 4 inch driver..
My good chap, "percussive energy" is a meaningless term - either the speaker reproduces the frequencies at the SPLs required, or it doesn't - it's as simple as that, ;) ...

What you're talking about is the ability of the system to be able to create realistic impact, replicating what real instruments achieve trivially - which the majority of setups can't do, most of the time. I have mentioned many times going to the Sydney hifi show, where there was only one system, on the day, that was able to do that - lots of bluster and thundering from some gear, trying to get something more impressive happening - a bit like the big talker down at the local watering hole ... :D

For the 9,999th time, getting sound working like it should is a system issue, not a speaker issue. Pro speakers in a solid cabinet is a handy shortcut, but no guarantees - a pricey, ambitious JBL horn system at that show dissolved into standard PA thrash once a bit of volume was asked for ...
 
I tried that organ sample on bcarso's PC monitors, and this is where quality comes into the picture - they can do down to 100Hz, sharp cutoff below that, but they are built to a price so, reproducing the notes at the bottom end of their range provokes 2nd and 3rd harmonics very low in the volume range, the left speaker is much worse than the right, and if the volume is really pushed all sorts of other harmonics and 'noises' climb on board, :). This then limits the volume they can be driven to on that organ sample, a.wayne's "mud" intrudes - but if one judiciously uses the volume control to not overly encroach into that region then the organ comes across nicely.

However, if the driver had been built sufficiently well to limit the onset of those harmonics to much higher volumes then it would have given a much better account of itself. I have found, by experiment, that those drivers will also stabilise substantially by being driven hard - if I do it long enough then I can play certain tracks at the maximum volume setting with minimal audible degradation, the real limits are the tiny power supplies that go with the units.
 
Last edited:
The only thing that I can tell is not 'hi fi' is that they do 'forgive' the sound quality, rather than let the irritation through.
This is one of the "magics" of audio, :rolleyes:: two speakers, reasonably similar FRs - one is 'forgiving', has special "cleverness" built in so that it can detect undesirable distortion from earlier on in the chain, and nips it in the bud; the other, "premium" unit, spends a lot of money removing that cleverness, so that the pure, "raw" sound with all its inherent distortion is now fully, gloriously revealed ...

Interesting, that ... ;)
 
Status
Not open for further replies.