Markaudio CHP-70 Project

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#21
spekr said:
It needs some equalization though to reduce the 5-10dB step above 10kHz.
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If you EQ out the peak on-axis, you will reduce the response by the same amount at 15*. As yourself -- are you going to to listen to your speakers directly on axis, or are you going to toe them in/out some number of degrees? I've been playing with the A10, which go dead flat at ~30* off axis, and that is where I listen to them. Your A7's are flat at 15*. No EQ required.

Bob
 
#22
Bob Brines said:
If you EQ out the peak on-axis, you will reduce the response by the same amount at 15*. As yourself -- are you going to to listen to your speakers directly on axis, or are you going to toe them in/out some number of degrees? I've been playing with the A10, which go dead flat at ~30* off axis, and that is where I listen to them. Your A7's are flat at 15*. No EQ required.

Bob
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I don't consider the response at 15° in my measurements as particularly flat. So I would use EQ anyway.
Equalizing in relation to 0° will result in way less variance throughout the listening window than equalizing to 15°. Here's a comparison.

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#24
Bob Brines said:
You just refuse to get it,don't you? You simply have to have the last word, even when you haven't a clue what the question was. And don't bother to respond to this post. I'm done.

Bob
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Your question was "are you going to to listen to your speakers directly on axis, or are you going to toe them in/out some number of degrees?"

My measurements show that there's less variance around 0° and a lot more variance around 15° hence the response will be much smoother within the listening window around 0° after EQ. This is how I would listen to the speaker in a stereo configuration - toe-in of 30° so the speakers point at the listening position.
 
#25
Scottmoose said:
I have to an extent, but I haven't made detailed comparative studies. All materials vary somewhat in their behaviours / the efficiency of their damping at various frequencies. So densities of stuffing may need adjusting accordingly if these are altered. Augspurger has written on this subject and provided a few examples with measurements. Long hair wool works well -it was the favoured application for TL damping for years, although that had as much / more to do with limited choice in the 1960s / 70s & the rise of myth as anything else. It needs to be treated to prevent problems with moths (not a joke). Your local farm supplier's wool will probably do fine if so treated, but I doubt you'd see any superiority over, say, Acoustastuff or similar. Nice to support local suppliers when practical however.

FWIW, I just tend to assume a decent quality hollow-fibre polyester (Dacron) unless otherwise stated. There's always a degree of variability, but it serves as an average baseline.
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Thanks Scott, I appreciate it.
 
#27
CHP-70 QC issues

Hi all

Please , have you been informed or experience any problem regarding quality on CHP - 70.2 drivers ? An european shop got its whole stock rejected due spec problems . So they were not able to send me a quotation. Sounds unusual indeed .

Thanks for comments
 
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