The sonic benefits of an active crossover. A discussion.

[microstrip]

(...) I recently read this review of a DSP active speaker:
http://www.hificritic.com/downloads/digital/HIFICRITIC_MeridianDSP7200.pdf

(...)

Using this review in an active versus passive debate is a double sword - a few sentences bellow the reviewer states:

" First impressions were of a considerable achievement, as a result of the time-corrected bass, the smooth phase control, and the sweet sounding digital replay filter, but then some doubts set in. While greatly enjoying it at first, I found that it could not fully hold my attention, and I began to imagine subtle errors, colorations, and frequency imbalances, as excuses to explain my mild dissatisfaction.
It somehow sounded too too polite, even soft, and while there was still much to admire, I began to feel that it also verged on a kind of musical wallpaper. My objective senses fought my emotional response, leaving me in some confusion over the sound of this speaker.
I now recognised some observed lack of dynamic expression as a significant flaw. The sound was somewhat soft and slow with a slight lack of contrast, and I was sure that this was not due to the new apodising filter which had sounded so good when using Meridian’s CD player in a conventional system."

Fortunately just changing the digital input from the Meridiam system to ordinary SPDIF changes everything and the speaker become wonderful.

Considering the shown measurements it seems to me that the great sound qualities of the GBP 17500 DSP 7200 are due to many other factors than just being an active. As said by the reviewer:

"At last we could clearly hear the balance of engineering design guided by Bob Stuart’s view of important psychoacoustic weighted parameters – and it works. " For me this is part of part of high-end and considering Bob Stuart long time credentials and resources involved in this speaker I am not astonished with the result.

 

[Groucho]

Using this review in an active versus passive debate is a double sword

Yes, he says he begins to hear subtle defects but that this is due to some problem with the digital link which he 'proves' by finding that SPDIF restores the fantastic sound - so I don't think that can be levelled as a criticism against active speakers per se.

Considering the shown measurements it seems to me that the great sound qualities of the GBP 17500 DSP 7200 are due to many other factors than just being an active. As said by the reviewer:

"At last we could clearly hear the balance of engineering design guided by Bob Stuart’s view of important psychoacoustic weighted parameters – and it works. " For me this is part of part of high-end and considering Bob Stuart long time credentials and resources involved in this speaker I am not astonished with the result.

The reason I quoted the review earlier was as a counter-argument against the suggestion that there is no audible difference between active and passive speakers, as apparently demonstrated in comparisons between active and passive versions of the same speaker. Martin Colloms clearly thinks that there is an unmistakable sound of active speakers, as do I:

It’s unquestionably ‘active’, with the grip, near effortless dynamic range, convincing integrity and authority that is typical of the breed.

I don't think anyone is arguing that this sound quality is due to good frequency response alone - although the DSP designer can make the frequency response as flat as a ruler if he wants to when measured from one point in space. Naturally, the response will not be ruler flat at all points in a real room. The arguments for active speakers go beyond frequency response and centre on damping, distortion, time alignment, phase correction, isolation between drivers, gentle loading on amplifiers, limited bandwidth requirements for amplifiers. Passive speakers can be given a perfectly flat frequency response too, but that will still not begin to address these other factors that make active speakers great.

 

[c1ferrari]

Earl was commissioned to build an active version of his Summas, and did so. He compared that version side-by-side with his passive version and what he told me was that there was no audible difference, and so he would never build an active version again.

Duke,

Would you have knowledge of the amps he was running with the passive version?
Thanks.

 

[Duke LeJeune]

Duke,

Would you have knowledge of the amps he was running with the passive version?
Thanks.

'Twas a Pioneer receiver. I don't remember the model. After Earl and Lydia Lee published their study of distortion perception, Earl measured a bunch of amps to see which ones fared well according to their perception-conscious metric. The Pioneer stood out from the rest, and so that's what he uses.

 

[alkaloid]

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Page 7 and 8. Very detailed explanation of benefits to bi-amping. Please read. Less power loss, less IM distortion.