I want to thank MBK and John K for the very interesting and illuminating measurements they've provided over in the Adventures in Cardioid thread. This definitely gives me something to work on with the single or paired Altec/GPA 414's and/or 18Sound 12NDA520's.
The impulse response of the resistive "muffler" at different emission angles was especially interesting - shown below. (Top graph is 0 degrees, next down is 7.5, the middle is 15, the next is 22.5, and the lowest is 30 degrees off-axis.)
The impulse response of the resistive "muffler" at different emission angles was especially interesting - shown below. (Top graph is 0 degrees, next down is 7.5, the middle is 15, the next is 22.5, and the lowest is 30 degrees off-axis.)
Attachments
Lynn I ran across this guy selling autoformers
http://cgi.ebay.ca/New-Audio-Autotr...963961&_trksid=p3286.c0.m14&_trkparms=72:1215|66%3A2|65%3A12|39%3A1|240%3A1318
What does one look for in a quality autoformer for audio use? What do you think of these?
http://cgi.ebay.ca/New-Audio-Autotr...963961&_trksid=p3286.c0.m14&_trkparms=72:1215|66%3A2|65%3A12|39%3A1|240%3A1318
What does one look for in a quality autoformer for audio use? What do you think of these?
Talk to Dave Slagle here http://www.intactaudio.com/ for excellent autoformer's or PM me for even better audio isolation step downs or off to Kevin at K&K here, http://www.kandkaudio.com/digitalaudio.html
for Lundahl items
Bud
for Lundahl items
Bud
gedlee,
I agree completely. no transformer is better than the best one built. However, the resistor quality must be very high. And then, some folks seem to like what a transformer does to the "speed" of transient leading edge information, allowing them some more time to comprehend what is being portrayed I suspect. Others find this sort of spread out character offensive.
In a general sense the fastest items are going to come from Lundahl amorphous core, the most informative from me and Intact is somewhere in between. Interestingly a transformer vastly outperforms any opamp, as a buffer stage to a DAC, unless the opamp has some form of ground plane, or a stand in that holds electrons close to the opamp for control of dielectrics, for electrostatic moments. At that point it is a draw, except for the spread out in time of leading edge information from the transformer.
All of this from my experiences of course.
Bud
I agree completely. no transformer is better than the best one built. However, the resistor quality must be very high. And then, some folks seem to like what a transformer does to the "speed" of transient leading edge information, allowing them some more time to comprehend what is being portrayed I suspect. Others find this sort of spread out character offensive.
In a general sense the fastest items are going to come from Lundahl amorphous core, the most informative from me and Intact is somewhere in between. Interestingly a transformer vastly outperforms any opamp, as a buffer stage to a DAC, unless the opamp has some form of ground plane, or a stand in that holds electrons close to the opamp for control of dielectrics, for electrostatic moments. At that point it is a draw, except for the spread out in time of leading edge information from the transformer.
All of this from my experiences of course.
Bud
Build a preamp and put separate, solid copper plate either on the PCB, under the circuit components, or preferably, as a separate plate, with components wired in the US Navy fashion, symmetrically, direct connected laterally, dropping to the copper plate for ground reference. Keep the power plates separate from signal right back to chassis ground / service ground. Then build a duplicate, without any ground plane.
Or come join the fray here
http://www.diyaudio.com/forums/showthread.php?postid=1213239#post1213239
Don't give up until you get to Dave Davenport's post on the subject.
Bud
Or come join the fray here
http://www.diyaudio.com/forums/showthread.php?postid=1213239#post1213239
Don't give up until you get to Dave Davenport's post on the subject.
Bud
I share your frustration when it comes to audiophile terms. But since they are potential customers, a better way is for the designer to try and bridge the gap audiophile terms and technical terms.gedlee said:
One thing I have found is that in many measurements where I find high low frequecy noise, the sound is less "transparent" and the "speed of transient" is not so good. Resonances or slow decay in the frequency range 18KHz~30KHz will also reduce the so called "speed of transient".
I once had to receive high performance jet flight training so that I could understand pilot language. Maybe you want to join the audiophiles some time.
It's fun. Talk about the "loser runs nude" audio system shootout here...
I had a very interesting experience last week. Listening to only one speaker, I found that certain instruments would seem to move away to one side of the speaker. The cause? Heh, frequency response differences of the ear. Now the question would be whether or not to consider equalization to conmpensate for different response of the ears.
soongsc said:I had a very interesting experience last week. Listening to only one speaker, I found that certain instruments would seem to move away to one side of the speaker. The cause? Heh, frequency response differences of the ear. Now the question would be whether or not to consider equalization to conmpensate for different response of the ears.
On a side note... in high end car audio competition..
We match L & R by averaging frequency response from multiple mic readings at the listening position.. this does wonders for fixing image smearing, timing, and eliminating a side biased presentation...
Not that most of you would be interested..lol
Hi Bud - thanks for the link - was an interesting reading for my afternoon - I'm more clear what you are after now - though still don't know whats the "Navy fashion" (well I'm from the Alps - no sea around ).
Curious as always - I gave the speaker grounding mentioned there a try as I didn't have time to wind your loops right away (a lot needed for five speakers each side ).
Basically the same as described for your loops - less hash and of all its impacts.
(Maybe I should add that I have tried this centuries ago and haven't noticed a difference worth then - and forgotten about in the meantime)
Hi Earl - this ain't a topic for you! Its diametral to your believes in science - or better put - in what you think known science does not allow to possibly be another facet of reality!
Some time back I did a lot of investigation in power supply and came up with the result that a specific but repetetive arrangement of shilded cable connnection works considerably better than anything else I have tried.
It was based on "good engineering practice" (also outlined in some papers linked in Bud's thread) regarding return path considerations but went further than usually applied.
Effects were not too far from Bud's (others and mine as far as outlined) impressions about his black magic (?) parts.
So I don't go (to much) with the explanations given there but with what to be heard...
Michael
).Curious as always - I gave the speaker grounding mentioned there a try as I didn't have time to wind your loops right away (a lot needed for five speakers each side
).Basically the same as described for your loops - less hash and of all its impacts.
(Maybe I should add that I have tried this centuries ago and haven't noticed a difference worth then - and forgotten about in the meantime)
Hi Earl - this ain't a topic for you! Its diametral to your believes in science - or better put - in what you think known science does not allow to possibly be another facet of reality!
Some time back I did a lot of investigation in power supply and came up with the result that a specific but repetetive arrangement of shilded cable connnection works considerably better than anything else I have tried.
It was based on "good engineering practice" (also outlined in some papers linked in Bud's thread) regarding return path considerations but went further than usually applied.
Effects were not too far from Bud's (others and mine as far as outlined) impressions about his black magic (?) parts.
So I don't go (to much) with the explanations given there but with what to be heard...
Michael