A little more Zing up Top ?

[joyspring]

GM / Old Guy:

Yes, DSP can make a not-so-good room acceptable but no more really. Suppose that would address the average living room.

However, in a (close-to) proper room, it can be phenomenal and definitely widen the listening area appreciably.

The Audyssey in particular not only addresses frequency response but also time domain because it uses FIR filters as opposed to IIR. This was just a dream only twelve years ago but now embedded CPU cycles are inexpensive enough to include in consumer receivers

Those Denons, do you consider either/both of them as being suitable for HE hifi or only for HT and/or when combined with a studio's massively adjustable system and much superior acoustics to a typical listening room?

<font size="2" face="Verdana, Helvetica, sans-serif">All of the above. I cannot stress enough the importance of room acoustics in domestic listening environments (most seem to focus only on the equipment) but the Denon DSP receivers do an excellent job of addressing typical response anomalies.

IMHO, this DSP is equally applicable to high-end as well as home theatre.

For pro use, these receivers allot some degree of consistency between rooms, within limits of course. It helps us achieve repeatable results, which is of paramount importance.

And this DSP functions well over a fairly wide listening area. It uses clustering rather than averaging to achieve this. The Audyssey website includes a brief description in their FAQ.

Denon uses two lines of Audyssey MultiEQ; they differ in bandwidth resolution. Since I couldn't afford two of the AVR-4306s, I opted for two of the AVR-3806 instead...

BTW, anyone interested in six Crown D-75 amplifiers and two Outlaw 950 5.1 preamps, feel free to contact me via email.

On a similar note, QSC DCA series amps appear to be quite popular with very high SQ mixing stages, so any thoughts for home hifi if you have some personal experience with them?

<font size="2" face="Verdana, Helvetica, sans-serif">Nice amplifiers; I'd really like to pan them since I used to work for one of their direct competitors when QSC wasn't producing the high-quality product that it is today (they grew directly out of aggressive marketing in the late 80s/early 90s IMO).

We have the DCAs in our university theatre. See the other thread (Amazing how small, the jbl hartsfield) to view our JBL LCR setup...

Convenience-wise, they have very low quiescent consumption and the low inrush current is quite nice.

Hmmm, performance-wise, very low noise floor, flat frequency response, low distortion within its rated bandwidth, relatively high input and low output impedance... what's there not to like?

However, the cooling fans are noisy so unless they're relegated to a separate, acoustically isolated space, they're probably not so suitable for home use.

WRT piezos, good ones have their uses even in high end audio IMO, but until this thread I hadn't read one where I thought they were a viable option, especially since my understanding of the general consensus of this forum is that there's nothing worth reproducing above ~16 - 20 kHz (depending on who you ask) where some of the better piezo models are in their element, so to speak.

<font size="2" face="Verdana, Helvetica, sans-serif">Indeed. Meyer used multiple venerable KSN1005s in a few of their systems during the 80s.

I've noticed the same consensus myself; rather ironic since it also seems to be the consensus (well, at least a significant majority) that 44.1 kHz digital audio is inferior to analogue because of poor `resolution' and purported phase anomalies because of the steep filtering (long resolved w/ better filters and oversampling) near the Nyquist frequency. But that's a debate I won't restart...

For me, the 16 - 20 kHz range is important for domestic hi-fi reproduction, especially for recordings of live acoustic performances - classical and jazz in particular.

While the actual shape of the transfer response in that range might not be discernable, the total amount of acoustic energy in that bandwidth is. To me, at least.

Still, it was years later AFAIK before whoever it was that figured it out and many years later still that JBL/Altec designed the work around solution of the A series multi-driver truncated bass-horn

<font size="2" face="Verdana, Helvetica, sans-serif">There's always the tap dancer story that we're familiar with. Thank goodness that Altec addressed this, and further thanks to Heyser, Blaurt, Laws, et al. who helped quantify the audibility of time offset.

BobR

[GM]

Greets!

DSP is nice, but my limited experience with it still leaves a lot to be desired compared to acoustic solutions in that it has a very narrow height/width/depth 'sweet spot', though the one install where it was used to fine tune an acoustically treated room was pretty impressive.

Those Denons, do you consider either/both of them as being suitable for HE hifi or only for HT and/or when combined with a studio's massively adjustable system and much superior acoustics to a typical listening room? On a similar note, QSC DCA series amps appear to be quite popular with very high SQ mixing stages, so any thoughts for home hifi if you have some personal experience with them?

WRT piezos, good ones have their uses even in high end audio IMO, but until this thread I hadn't read one where I thought they were a viable option, especially since my understanding of the general consensus of this forum is that there's nothing worth reproducing above ~16 - 20 kHz (depending on who you ask) where some of the better piezo models are in their element, so to speak.

As for piezo XO designs, I've normally just used a 1st order, so the corner frequency has typically been in the 15 - 25 kHz range, but for a 299 it will need to be at least a much lower 2nd order if you want it to sum OK with its natural roll-off.

Yeah, the insertion loss of that many passive components wouldn't leave any power handling worthy of the description. Still, it was years later AFAIK before whoever it was that figured it out and many years later still that JBL/Altec designed the work around solution of the A series multi-driver truncated bass-horn, though I assume WWII was a major reason for such a long time span between understanding and an elegant solution.

GM

[GM]

Greets!

Good to know about the Denons, thanks!

Yeah, you're 'preaching to the choir' with me about room acoustics/acoustic solutions to acoustic problems.

Well, not all of QSC's early popularity was hype , I brutally abused a USA900 for months on end driving a 0.89 ohm load to clipping on a regular basis. My main complaint was its limited useful BW. Anyway, thanks for the mini-review. I wonder if they can handle reduced cooling fan speeds for less demanding HIFI apps?

I agree, even though my hearing has rolled off significantly in recent years I can still 'hear' much of the HF on a good wide BW recording through eyes, skin, etc., 'feel', though I must be pretty much on axis based on comparing off axis response with a teen. What he was strongly hearing at 16 kHz/-90 deg, I was done at ~15 deg. Still, ~30 deg. is enough in most HIFI apps and all properly set up HTs. If nothing else, scratchy/hissy vinyl isn't as distracting as it once was, though some ancient cassette tapes are still horrible and CDs brick walled at 20 kHz still sound dull.

Indeed, but who was it that actually came up with the HF horn's extreme off-set to get rid of Eleanor's echo?

GM

[Todd W. White]

Dr. John K. Hilliard was the recording engineer who discovered the problem using the WE speaker system provided by Bell Labs. When he called them to tell them what he found and how he fixed it, they didn't believe him. Apparently, it took a visit to hear it for themselves to convince them...

[bfish]

For Dr. Hilliard's own recount, see page 2, column 2 of the AES article;

An afternoon with John K. Hilliard

[GM]

Greets!

Todd,

Thanks, I should have guessed!

bfish,

Great article! Thanks for sharing!

GM

[ngccglp]

My current set up is 1005/288 on top of the 828. I have a spare 511B/802. Always wanted to try to make a 3 way - stacking the 1005 on top of the 511 on top of the 828. What would be a good crossover freq and will I face phasing problems if I just follow the original recommended distance of 19.3 inches for the VC?

Thanks

[GM]

8 kHz.

Well, you want to be at least within a 1/4 WL of the XO point, so at 500 Hz you can be off quite a bit, but at 8 kHz it's only a ~7/16" 'window', so you may want to experiment a bit to see if you can hear any difference worth changing it.

[ngccglp]

Hi GM,

I did it! I will post picture soon. I DIY a JBL N7000 XO; made a wooden shelve that just cover the 511B, then stack the 1005 on top. Both VCs distance 19.3 inches from front of cab.

First impression: sounds more open, less congested. I did not add LPad for the high, so far the levels of the 802 and 288 seems quite balance, so no urge to add LPad yet into the N7000. Now I think I have to sit further way for the sound to blend nicely.

Will report back.

[ngccglp]

I don't know how to upload pictures here, please check out my Avatar. I added a LPad to the 288 to balance the level of the 288 and 802. Its easier to fine tune the pitch of instruments now by varying the levels of the 802 and 288. Sounds good so far. May upgrade the caps of my DIY N7000 soon.