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In the Forum: Horn-Loaded Speakers
In the Thread: Macondo’s Midbass Project – the grown up time.
Post Subject: Taking turns out of coils in search of prodigious balancePosted by Romy the Cat on: 11/9/2010
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 haralanov wrote: |
| Are there any signs for worsened transient response of your midbass channel due to the sharp electrical filtering? |
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Nothing that I note. The transient response of your midbass channel is a bit tricky thing as the way how the midbass is blended and calibrated as now make it very difficult to feel the midbass itself. Remarkably it feels that all midbass noted are coming from upperbass channel and I do feel that midbass transient are dictated by upperbass and lower midrange. Listening the midbass channel itself is very interesting – it is not musical in a way how my upperbass is. The sound of midbass channel is pretty much the sound of artifacts. combined with the rest of the system it doe the right mix of actions.
BTW, I need to point out that the way I implemented the midbass crossover make sound less likely to experience the negative effects of sharp electrical filtering. My filter is fixed second order filter in the amp input. The filter is written against fixed impedance and made as close as possible in this topology to Bessel curve, presuming the minimal phase distortion. Then, after the amp there is a first order filter, that is by nature is Bessel with minimal phase distortion. What is important that the first filter does not see the second filter, so any ringing associated with high electrical filtering are not applicable.
In the very best world I would put 1st order before the amp, the second 1st order between the stages of the amps and then the last 1st order in the speaker level. This I would decouple each stage of filtration. How much practical impact it would have is very hard to say. Who said that I need a perfect text-book roll off characteristic for a given amount of dBs per octave? I need a properly sounding midbass channel, this is more important than to know that I have 18dB/octave at minus 6dB and 14dB/octave at minus 15dB….
Anyhow, the bigger thing to me now is to find a very prodigious balance between the feelings of midbass time mis-alignment and the longetivety of the midbass decay. What I observe is that making the midbass tail a bit longer I might mask out to a degree the fact that midbass leading wave is delayed. I do cruse around a good configuration but I did not hit the perfect one yet and did not lock it yet. I think it will be somewhere between 130Hz and 155Hz of the second filters. I would like it to be set absolutely right, in the middle of any type of music and any type of recordings. I am absolutely confident that I will be able to do it but it takes time to listen and the time to take the turns out of those coils…
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