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In the Forum: Playback Listening
In the Thread: Be careful: Imaging vs. Compression
Post Subject: Re: Crossovers, phraseology and the holesPosted by Gregm on: 2/16/2006
 Romy the Cat wrote:
Even if it is possible with a given (multichannel, faulty design) loudspeaker then the DPLOS become very fragile and appears/appears too sudden, without a gradual improvement while approaching the DPLOS. The keys are phase coherency and … surprise, surprise a compliance of the individual drivers between each other.


This was exactly the case -- figuratively speaking, the last mm makes a strong perceptible difference. (And this looked very silly from the viewpoint of another person in the room looking at me touching the bottom of a spkr -- and doing visibly nothing, but the sound changed.)
 Romy the Cat wrote:

Higher order crossovers produce less “maximum amplitude” at the level #3 (my post above) of the DPLOS proximity. Any deviation of crossover from 6db per octave severely minimized articulation and expressive capacity of a loudspeaker. The impedance normalization networks and any resonating chains completely kille it.
...
Ironically 12dB per octave coming from a mechanical device (for instance cut off due to the size of a horn bell) instead of electrical resonating chain do not affect Sound so negatively.

Again, exactly my experience. To state the obvious: given the engineering compromises allowed in the design of the spkrs there seems to be an (equivalently compromised) "optimum" in approaching the DPLOS. 
OTOH, the advantage of a mechanical cut-off seems quite logical; or inversely put, an equivalent electrical circuit has much higher variability (apart from the ubiquitous phase anomalies). I don't mean infinitessimal changes perceptible only to a platinum ear -- I mean our beautiful, 1kHz @ 3volts (let's say) xover, complete with designer components that slips to 0,5kHz (just an example) at 5 volts. With a 6db electrical, you have to work very hard getting things right around that xover -- but, at least, it operates more or less predictably thereafter...

 Romy the Cat wrote:
(the new) location is closer  (luckily) to the DPLOS then the original was.

Indeed Smile !  One of the bonuses of working hard to place the spkrs in the first place!

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