The fundamental problem, along with the need for careful alignment of record and playback operations, with these noise reduction schemes: they are always altering attack transients, by virtue of causality. If on the other hand there had been an easy way to introduce delay in those days, so easy in the digital domain, the problems could be alleviated.
I found Dolby B to be bearable. C was just too much. Dbx I never auditioned (or was unaware if I did).
I found Dolby B to be bearable. C was just too much. Dbx I never auditioned (or was unaware if I did).
Christophe, I didn't mark their statements because I disagree with them, but all you need to do is to search right here, a few thousand (or perhaps a few tens of thousanbs of messages ago). I brought it up twice, been some time, and I mostly got dismissals or was ignored.
I am not saying that Fletcher-Munson got it all just right, but I do think they make a good point. Truth be said, the industry itself is much to blame for that because in the late 70ies, during the Specs Wars, everybody was trying to outdo everybody else, which brought about the range of tone controls and loudness to truly amazing ranges, way out of what one would actually need. A few manufacturers (notably Yamaha, Marantz and a few others) replace a simple on/off loudness compensation switch with full range pots, allowing the user to select his own compensation. Speaking strictly for myself, I soon found out that what I liked was well below the average as provided in most amps, with very few exceptions. Some compensated for low frequency only, others got the relationship between low and high frequency compensations all wrong the thrud group had a "linear" switch, used to remove all compensation as the default setting was not off, but on (quite a few popular German brands, for example, such as Grundig, Telefunken, etc).
I am pleased to note that my Luxman C-03 preamp has, in my taste, a very well judged loudness control, about just right for SPL levels I normally use for all day listening.
You are right. And, (on my opinion) in a very dishonest way. Both about their commercial practices and on a technical point of view.
When the digital tape recorders appeared, it was obvious that no one will never need their noise reduction system any more.
So they turned to the movie market (less washed than the music one) and tried (with success) to make believe in some king of magic, selling systems with pseudo 3D and their old noise reduction system for ten time the price. All that coming with a Label and an approval procedure for the studios...
Thz Dolby surround is/was really a mess. Like the quadriphony attemps on vinyls in the 70...
I have mixed views on THx certification. on one hand is it an attempt to make it so the buyer knows the equipment is up to the job (loud crash band wallop dinosaur on a movie) which is not a bad thing per se. On the other it seems a bit of a protection racket. 'Nice speakers, shame if they didn't sell cos they didn't have a THx sticker on them'
Of course.
I had build my own Fletcher and Munson corrector as a studio device. It was fast to add "presence" to any instrument (all along with parametric equalizers).
Just, on my opinion, It don't work so well to do what expected: Have a unchanged sound balance whatever the listening volume in a hifi system.
May I add that, in a strange way, some systems seems to stay pretty balanced with no corrections whatever the level, while others are losing basses and presence at low volume ? I don't know exactly why. An other mystery on the road ;-)
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The "standards" are notoriously lax. What does it mean to have THX certs for a teeny speaker, etc.? It means you paid them a lot of money. This at least is the way it was.
But I think the marketing/sales benefits of the mark are vastly overrated.
My old HP Pavilion g7 laptop has a couple of other marks of insignificance. Beside the horrible speakers on the front edge, there is the SRS logo on one side and an ALTEC Lansing logo on the other. I plug some desktops into the headphone output. It still sounded dreadful until I managed to turn off the SRS processing.
DTS purchased SRS, but not for the clumsy pseudo-surround approach.
A loudness control! I haven't thought about that control for years and years. Back in the 1960's, I used the loudness control in a Dyna PAS-3X tube preamp with good effect. But when we designed the Levinson JC-2 in 1973, we decided to go the 'purist' route and forgo any sort of tone controls, and I have been happy with the result for decades.
The problem with tone controls is that they can be so complex. Even a Baxandall tone control is not easy to make without compromising the thru-path.
As discussed here, the Cello (Burwen designed) Audio Palate is about as good as it commercially gets. I would like to have one, but I am too lazy to design one for myself. Still, I doubt I would use it much in reality.
They used to make 1/3 octave equalizers for a reasonable cost, and I bought a couple over the decades, BUT I could hear their 'signature' even in bypass mode, so I never really kept them in my playback system.
The problem with tone controls is that they can be so complex. Even a Baxandall tone control is not easy to make without compromising the thru-path.
As discussed here, the Cello (Burwen designed) Audio Palate is about as good as it commercially gets. I would like to have one, but I am too lazy to design one for myself. Still, I doubt I would use it much in reality.
They used to make 1/3 octave equalizers for a reasonable cost, and I bought a couple over the decades, BUT I could hear their 'signature' even in bypass mode, so I never really kept them in my playback system.
A relay can completely bypass a tone control if it is arranged as a side chain.
Some tone defeats work by forcing the tone control circuit itself to be flat - this is not strictly a bypass - in these cases I guess it is easy to have a less than pure sound.
I note with my implementation that there is no perceptible difference in sound with the controls set to flat or bypassed - a result I was very pleased to get. This is predicted by theory of course as well. The bypass is more of a comfort thing with a Baxandall tone control.
Some tone defeats work by forcing the tone control circuit itself to be flat - this is not strictly a bypass - in these cases I guess it is easy to have a less than pure sound.
I note with my implementation that there is no perceptible difference in sound with the controls set to flat or bypassed - a result I was very pleased to get. This is predicted by theory of course as well. The bypass is more of a comfort thing with a Baxandall tone control.
"Racket" ... my favorite word !
It's funny , I had a Z5300 THX (THx certified). Kind of boomy with a 70mm
flared port. I suppose they just paid off somebody for the "sticker".
I have the same Z5300 10" tang band driver with one of my slewmaster 200W
discrete amps. Combined with a 100mm port and that amp - twice
the THx certified experience.
Crazy how they can get certification with the little bridged LM3886
amps powering it. I've seen a lot of cheap (mid-fi at best) subs and
5.1's that get the "sticker" and truly suck !!
It's all about the money and marketing ... THx might not always mean
SQ.
OS
Long time ago (I was young ;-) we had in France an official measurement office.
"Laboratoire National d'Essai". With everything to measure HF, distortion, power, and a huge and very good anechoic chamber for speakers measurements. And other electric and mechanic ones (security etc.)
No label, companies just paid for the "certified' measurements. They rented their facilities for studies too. And the prices of the services were very fair.
"Laboratoire National d'Essai". With everything to measure HF, distortion, power, and a huge and very good anechoic chamber for speakers measurements. And other electric and mechanic ones (security etc.)
No label, companies just paid for the "certified' measurements. They rented their facilities for studies too. And the prices of the services were very fair.
my quick search yielded "The usable dynamic range obtainable with SR is 90 to 95 dB depending or tape speed, tape speed and operating level"
ftp://ftp.studer.ch/public/SwissSound/SwissSound23eJul88LR.pdf
which is less than perceptual noise shaped dithered RedBook - by enough to allow for analog "0 dB" being exceeded by the usual factors working into >10% 3rd harmonic from tape saturation
even more reasonable comparison would be the best dynamic perceptual noise shapers that put the dither noise in masked bands when there is any signal at all to hide it in
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Christophe, I said as much. In a race for more of whatever just so it looks better on the spec sheet very often perverted the basic intetion, and turned it from an aid to a perversion (like warm beer
). Lots of wildly boosted bass, wrong relationships between bass and high range, distortion of the midrange, you name it. It is a sad truth, but unfortunately it was mostly so. The only obvious exceptions were devices with a loudness pot, at least it could be made not to be so boomy. reVox A78 integrated amp had a novel approach - instead of boosting low and high range, it selectively attenuated the midrange, producing an attenuated but corrected sound. Like a combination of mute and loudness. Generally, it worked all right, but it had problems with exceptionally clean and clear input signal, when it compressed the dynamics so you could hear it.Right on!
I found that by trial and error in 1993 when I sold my open reel deck and went shopping for a decen cassette deck. At the time, the lastes was an auto calibration system everybpdy and their dog had. So I lined up 5 decks of interest to me from Denon, Technics, Nakamichi and Sony, all 3 head machines. Using TDK and Maxell tapes, I made the same recording many times over, no NR, Doly B, Dolby C and Dolby HX Pro. In the end, by elimination, I bought a Sony TC-K 808 SE, simply because I got the best replica of the LP sound on it, and that came from a manual system of bias and playback EQ. Sony stuck to it, I thought the Nak would wipe the floor with the rest, but to my surprise they were let down by their automatic bias system.
Sony came out a clear winner on both TDK metal and Maxell EE tapes.
You’ll need to set the Q of each filter.
From the diagram of Stereophile , the Q of the six filters seems to be as follows [Q= f0/(-3dB)BW]
20Hz: Q=1.54 (f1=13Hz, f2=26Hz)
120Hz: Q=1.06 (f1=72Hz, f2=185Hz)
500Hz: Q=0.57 (f1=200Hz, f2=1080Hz)
2kHz: Q=0.65 (f1=900Hz, f2=4kHz)
5kHz: Q=1.25 (f1=3.3kHz, f2=7.3kHz)
20kHz: Q=1.74 (f1=15.5kHz, f2=27kHz)
George
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Interesting discussion and pertinent as I often listen at very low levels at night when everyone else is in bed and, whilst I've never actually tested this repeatably I have come across speakers that 'seem' to only come to life as the volume is cranked up, whereas the ones that I end up buying do seem to sound find at lower levels. Conceptually this has never sat happily with me but never had enough time with enough systems to test if this is real or my imagination. Something else to play with when I get the miniDSP working.
Well, how to say, the spirit, now, is very different. And, as far as I know, there is not a lot of French hifi manufacturers left neither.
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