François
If you are happy that is all that matters.
But looking at that measured response I believe a filter would really help. The filter has to be tweaked to mesh with your other equipment and room.
I lived with the same type pf response from my FE-164 ML TQWT for many months and the pronounced midrange and high end definitely made the speaker sound dynamic and super detailed at the expense of the bass output. But I grew tired of this light low end response after a while and feel that the circuit really helped. There was no body or weight to the music without the filter, it sounded good but was just not realistic and lacked depth. This type of response is very appealing and does sound more open, but it is basically still out of balance. With the BSC filter nothing is lost or compromised, it is just returned to the right proportion in the sound level picture.
Putting a correction filter in series with a voltage driven speaker is the same as putting a filter in parallel with a current driven speaker. The filter adjusts the signal transmitted to the driver be it voltage or current. So any degradation added by a filter is present in both circuit/amp topologies.
If you are happy that is all that matters.
But looking at that measured response I believe a filter would really help. The filter has to be tweaked to mesh with your other equipment and room.
I lived with the same type pf response from my FE-164 ML TQWT for many months and the pronounced midrange and high end definitely made the speaker sound dynamic and super detailed at the expense of the bass output. But I grew tired of this light low end response after a while and feel that the circuit really helped. There was no body or weight to the music without the filter, it sounded good but was just not realistic and lacked depth. This type of response is very appealing and does sound more open, but it is basically still out of balance. With the BSC filter nothing is lost or compromised, it is just returned to the right proportion in the sound level picture.
Putting a correction filter in series with a voltage driven speaker is the same as putting a filter in parallel with a current driven speaker. The filter adjusts the signal transmitted to the driver be it voltage or current. So any degradation added by a filter is present in both circuit/amp topologies.
MJK said:
I always thought so until I tried it both ways - using a parallel
resistance with a current source and a series resistance with
a voltage source, which should be equivalent. Strangely
enough, they did not sound the same. Jon Ver Halen of Lowther
America reports similar results. I suppose we could chalk it up
to the intrinsic difference in the sound of the two amps, but that
is not what Jon thinks. Me, I see it as topic for additional
experimentation.
Nelson,
Where was the sound different? Was the bass and mid-bass different, was it diferent across the entire frrequency spectrum, or were the highs different in some way? How significant were these differences? I have not had the benefit of hearing a current source amp with my Lowthers.
I hate to draw conclusions until I have an apples to apples comparison. I see too many hard conclusions drawn and stated in audio based on a test of one variable in a system when the variable significantly impacts other things in the system response. For example, people conclude that a BSC is a bad thing based on putting it into a system with a 2 watt amp and having the amp run out of gas. The circuit is doing its job, the amp is the limitation. But the conclusion is that the circuit killed the dynamics of the performance.
The point I was trying to make was that series components are in the signal path for a voltage source amp and will have no effect on a current source amp. For a current source amp, parallel components are in the signal path while series components are not. I have seen people conclude that with the current source amp and parallel circuits that there is nothing in the signal path. This is based on the topology of the connections and not on the simple AC circuit theory. They have never heard of Thevenin and Norton.
Where was the sound different? Was the bass and mid-bass different, was it diferent across the entire frrequency spectrum, or were the highs different in some way? How significant were these differences? I have not had the benefit of hearing a current source amp with my Lowthers.
I hate to draw conclusions until I have an apples to apples comparison. I see too many hard conclusions drawn and stated in audio based on a test of one variable in a system when the variable significantly impacts other things in the system response. For example, people conclude that a BSC is a bad thing based on putting it into a system with a 2 watt amp and having the amp run out of gas. The circuit is doing its job, the amp is the limitation. But the conclusion is that the circuit killed the dynamics of the performance.
The point I was trying to make was that series components are in the signal path for a voltage source amp and will have no effect on a current source amp. For a current source amp, parallel components are in the signal path while series components are not. I have seen people conclude that with the current source amp and parallel circuits that there is nothing in the signal path. This is based on the topology of the connections and not on the simple AC circuit theory. They have never heard of Thevenin and Norton.
MJK said:
I agree with your points, certainly to the extent that the voltage
source and current source are purely that, which of course they
aren't. I've not had difficulties with BSC (baffle step correction so
well described on your site) , and I find them easy to do on with
a current source. I have been getting good results using values
between 10 and 47 ohms across the amp terminals (the amp
itself being 80 ohms).
When I go to simulate this with a resistance in series with a
voltage source (for me usually an Aleph 30) by placing the
resistance, something seems to take away the toe-tapping
qualities of the experience, as I said, contrary to my
expectations. I've done with with Abbys and Lowthers-in-a-box
and heard similar things. I recall Jon Ver Halen describing it
as having the "life sucked out of it", but in any case it was
different.
At this time, I regard it as an anecdotal thing, not a hard
conclusion. Someday I'll have the time to do a more
comprehensive set of tests to see if I can isolate it - certainly it
flies in the face of logic. I can only confirm that neither amplifier
was overdriven or otherwise distorting overtly.
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