John Curl's Blowtorch preamplifier part III

[vacuphile]

By example, when you says "flat on axis FR", if you mean with no major accident, I agree. If you mean horizontal, I do not. On my experiences, the most natural speakers (I hate those sparkling 'HIFI' speakers) need often, (often as a precaution) a slowly descending response curve. Not to forget that records are monitored in highly damped cabins, compared with brighter customers living rooms where, usually they listen to music. My Kef are flat, horizontal. Caricatural.

Tryphon, that is exactly what I meant with a smooth down sloping power response. Power response is the total acoustic output of a speaker in 360 degree sphere.

All drivers that are flat on axis exhibit a down sloping power response by physical necessity because of a phenomenon known as beaming. And this slope is smooth, unless the cabinet impacts negatively. The problem is with more way systems; the connection between drivers in the crossover region does not only have to be flat on axis, but should also not introduce wild movements in the power response.

Some horns have a relatively flat FR over a relatively wide listening angle. As to your KEF: the midwoofer will certainly exhibit a down sloping power response. But the tweeter horn may not. Will look for measurements on line.

 

[syn08]

To be fair he has, my problem is I want to see an example of an acceptable test plan that was actually carried out. IMO both "sides" are equally guilty and virtually everything posted here is anecdotal opinions of little or no value i.e. counting votes.

Can you or anybody else point me to this “acceptable test plan”?

 

[vacuphile]

OK I didn't look hard enough, still I don't consider -140dB unmeasurable. You can't plug it into an AP and make a graphic that everyone seems to want to see.

S/N is -140dB. Distortion is unmeasurable. According to Bruno. And he must have tried hard.

 

[vacuphile]

Mr. T, your ears have not been lying to you:

KEF LS50 Anniversary Model loudspeaker Measurements | Stereophile.com

There is too much lateral energy above the xover region, and it bulges. The result will be a speaker that sounds overly bright, even if on axis is is flat.

 

[scott wurcer]

S/N is -140dB. Distortion is unmeasurable. According to Bruno. And he must have tried hard.

A technique for measuring distortion to -180dB has been published. Just curious, personally this pursuit of numbers stuff is rather pointless IMO.

 

[Tournesol]

OK I didn't look hard enough, still I don't consider -140dB unmeasurable. You can't plug it into an AP and make a graphic that everyone seems to want to see.

If I understood well, Bruno said it was an expectation, as he reached the limit of the AP own distortion.

 

[Terry Demol]

Personally, I have nothing to do with 'fidelity'.
I am only interested in this matter to my selfish pleasure. It consists in trying to obtain, at home, the results, on a majority of disks (the sources are, as I said, imperfect) the results closest to those which I tried to obtain during my own mixes.

Fortunately, there is a cultural consensus among most sound engineers and musicians, and we can see it here too, so we can do it more or less.
This consensus is probably due to the daily attendance of musical instruments, and to many exchanges of listening impressions, exchanges during which we can not hear ... any number.

We will never be able to stop undergoing the permanent lessons of this bunch of objectivists in crusades to explain how to walk in a straight line in the deep of a thick mangrove ?


Moreover, listening to the current productions, I do not have the impression that the wonderful technological efforts, towards this utopian technical perfection of which they dream, helped to advance the musical artistic creation since the end of the 70's.
What to ask yourself, is not it?

Great post.

It's nice to see someone here displaying a real understanding of the *whole process from performance, recording, mixing, mastering and how it really impacts what we hear at playback.

T

 

[Tournesol]

It's nice to see someone here displaying a real understanding of the *whole process from performance, recording, mixing, mastering and how it really impacts what we hear at playback.

Thanks a lot, touched.
Happily, I'm not alone here ;-)

 

[Max Headroom]

What precision do you think you need to get this song recorded so that nobody can tell the difference to the original:
YouTube

Can you tell the difference to the ORIGinal ? - Lana Del Ray.


Dan.

 

[dreamth]

sorry, but for the moment the only source i can listen the right way is a cd player...it was a theoretical question...it is just a voice and a piano in the background.I saved you files and I'll listen to them in a month probably.

 

[Max Headroom]

You could burn to CD ? I can down process to 16bit if you want.
Dan.

 

[dreamth]

Better tell me what you want to say.I'd believe you!

 

[Max Headroom]

You are online, I presume you can listen on PC headphones ?.

I have posted three files, one is audio capture from the Youtube track you linked, the other two files are loopback recordings, one of which is 'clean' and the other is deliberately 'coloured'. My listening comparisons of this and other music have been between 24bit versions only, I am not certain how 16bit versions compare....I will audition 16bit shortly and maybe post files to DB.

I'm saying that you ought to be able to hear difference between 01 - ORIG and 02 - TS which is the quieter of the two loopback recordings. When you can reliably differentiate between 01 and 02 you can proceed to 03 comparisons, doing so earlier may cause confusion.

Dan.

Edit : 16bit versions posted to DropBox

 

[dreamth]

Unfortunately , the only laptop that can drive my headphones has one channel burned and buzzing.It used to be a very good headphones amp the one in my laptop .The external soundcard is dismantled...

 

[gpapag]

As to your KEF: the midwoofer will certainly exhibit a down sloping power response. But the tweeter horn may not. Will look for measurements on line.

You may have a look at this thread too
KEF LS50 playground - measurements of raw drivers in factory cabinets and simulations

George

 

[indra1]

... The upstream components are in this context of little concern since they have reached the point of development where by ear, the good ones have become indistinguishable. ...

Mediocre at best. Nobody would call a vinyl recording system good without the RIAA preemphasis. The upstream components has to minimize issues downstream to make a good system.

A technique for measuring distortion to -180dB has been published. Just curious, personally this pursuit of numbers stuff is rather pointless IMO.

Maybe for audio, I can not be sure. But the advancement of technique may be essential to upgrade something like LIGO, why pointless?

 

[vacuphile]

A technique for measuring distortion to -180dB has been published. Just curious, personally this pursuit of numbers stuff is rather pointless IMO.

As far as audio is concerned, I couldn't agree more. It's good sports, though. Plus it may provide desirable bragging rights for those in need of compensation. Like, mine is smaller than yours......

 

[dreamth]

Like, mine is smaller than yours......

🙂

 

[scottjoplin]

Pass HPA-1 is not good?

The £3500 headphone amp? I expect it's very good.

 

[scottjoplin]

Mediocre at best. Nobody would call a vinyl recording system good without the RIAA preemphasis. The upstream components has to minimize issues downstream to make a good system.

I can think of Dolby, have you any other examples?