John Curl's Blowtorch preamplifier part III

Status
Not open for further replies.
The developer of the diffmaker tool is a member of this forum and he could explain it much better, but i remember that the alignement of two files is using huge amounts of memory (subsample shifting) and therefore will not work well on longer/larger files.
As well as us, when we try to make listening comparisons ;-)
The trade-off is to repeat the analysis with several short enough different samples, carefully chosen. Like we use to do ;-)
 
Member
Joined 2014
Paid Member
On my point of view, the most important part is to get the same directivity between the two transducers at their crossover frequency. IE, the same emitting surface. I do not know any other easy solution to get this but horns.
Bruno is clever.



I am sure that, if some goes from horns to cones, it is because... they used poor horns+drivers. Not surprising as it is not easy to find good ones.
Closed mind in operation here?




Yes that's the one. Some nice, polite adult level conversation on a topic. At least until page 3 where the armchair Toole bashers come out.
 
www.hifisonix.com
Joined 2003
Paid Member
Based on comments on this forum the LS50 is exceedingly polarising, which in itself is intriguing.

Nah. They are very, very good.

US listeners tend to prefer ‘forward’ sounding speakers (Revel, Magico, JBL) but the Brit sound is a bit more ‘reticent’ and I’d say ‘relaxed’.

Dali’s seem to be somewhere in between.

Just my observations.

Each to his own.

Peace.
 
The developer of the diffmaker tool is a member of this forum and he could explain it much better, but i remember that the alignement of two files is using huge amounts of memory (subsample shifting) and therefore will not work well on longer/larger files.

I have not read the paper but sub-sample shifting does not mean creation of more samples. It can be done with phase rotation in the frequency domain. From a brief look at the output of the process huge FFT's are used possibly as big as the entire sample (?).
 
www.hifisonix.com
Joined 2003
Paid Member
Nice article T.

Funny he says that JBL and Revel follow the Toole frequency response model like the KEF’s but when you listen to them you get a different impression. I would never guess in any event that the KEF’s sloped off as much as they do.

I also use a sub with mine - but I doubt it’s anywhere near as well integrated as Mitchco’s set up - I just dialed mine in until I liked the sound.
 
Bruno is clever.

Closed mind in operation here?

Yes that's the one. Some nice, polite adult level conversation on a topic.

Nice, polite, adult .. like your answer ?

Apart from expressing your dislike to me, by systematically contradicting me in an agressive way, what you do regularly, that shows the quality of your "open mind", you would have, for once, an argument to oppose mine.
(do not take this trouble, I will not read your answer.)
 
Disabled Account
Joined 2012
As HF harmonic distortion produces harmonics upper in the frequency range, which we are not supposed to can hear and that speakers will reject anyway because , usually, they do not produce any sound upper than 40KHz, don't you think it should be better to look at IM distortion in presence of HF components that can produce artifacts in the audible range ?

Yes. for sure.

though the tweeter cant reproduce it.. it does produce heat and offset.

-RNM
 
Member
Joined 2014
Paid Member
Nice, polite, adult .. like your answer ?

Apart from expressing your dislike to me, by systematically contradicting me in an agressive way, what you do regularly, that shows the quality of your "open mind", you would have, for once, an argument to oppose mine.
(do not take this trouble, I will not read your answer.)


You basically told horn owners if they don't like their horns then its their speakers at fault and get at me for being rude? PMSL
 
I have not read the paper but sub-sample shifting does not mean creation of more samples. It can be done with phase rotation in the frequency domain. From a brief look at the output of the process huge FFT's are used possibly as big as the entire sample (?).

What surprised-me in this article is the curve of the differences is descending. I was expecting a clear increase around 20KHz as an effect of the bric wall filters and the fact that one wave have less and less samples as frequency increase.
 

Attachments

  • imageproxy.jpg
    imageproxy.jpg
    161.4 KB · Views: 199
Disabled Account
Joined 2012
Nice article T.

Funny he says that JBL and Revel follow the Toole frequency response model like the KEF’s but when you listen to them you get a different impression. I would never guess in any event that the KEF’s sloped off as much as they do.

I also use a sub with mine - but I doubt it’s anywhere near as well integrated as Mitchco’s set up - I just dialed mine in until I liked the sound.

The measured response in my system with M2 do NOT roll off.


-RNM
 
You basically told horn owners if they don't like their horns then its their speakers at fault and get at me for being rude? PMSL

An exception to my resolution. (Curiosity, when you hold us ;-)

I bothered to write "I am sure that ..." and that means it was a personal and subjective opinion (I do not know anything of the systems used by people I do not know).
And the reason of this opinion is that the good horns (spherical waves and highly damped) are VERY rare on the market.
Most of the horns I had listened to (a lot) are just awful.

The second reason is I had never seen an owner of GOOD horns(or good waves guides) going back to cones. NEVER.
Ask Richard.

And your "PMSL" reveal a lot about your elegance, your friendly attitude and the way you design arguments when discussing a technical subject.
 
Last edited:
How many people are using amplifiers right now which has a thd curve shaped like this one: THD rising up at the high end but cut off at 20Khz? if measured to higher frequency we would see gross levels of THD.

View attachment 744440

Nobody on the planet has an amplifier that has thd curves like that.

I can say that with absolute certainty.

However, if you go to my gallery and click on the image labelled inductor R characterization, you will find a color version of that graph, but with the vertical axis label "resistance, ohms", and the legend on the right indicating which inductor and against copper or in air.

Um, Richard, your link pulled up the wrong picture...

John
 
Status
Not open for further replies.