DBX SNR-1, The Best Choice 4 No Hiss

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aquadad

400 Club - QQ All-Star
Joined
Feb 6, 2005
Messages
449
Location
Hillsboro, OR
Hello,

I am always amazed about the amount of discussion on the subject of whether or not to use noise reduction. Maybe it's because of misinformation about how it works. The SNR's do not take out a frequency of sound like an EQ. When they are dialed in correctly they ride the music signal and take out everything over and above that, leaving the music signal intact without the nasty tape hiss. Although this may seem to good to be true, it's really not and it works marvelously! The downfall to the success of the SNR's was never about it's ability to remove tape hiss successfully, it was about it being introduced into the marketplace at around the same time as CD which made it instantly obsolete. It didn't help matters that they were also expensive technology at the time. But make no mistake they do work flawlessly. As with any hardware though, there is the potential of an operator error in using this device properly.

The next time there is a discussion of whether or not to use noise reduction, maybe the question we should be asking is, "What kind of noise reduction, and, do you know how to use it properly?" I get so tired of this blanket statement of, "Oh no don't use noise reduction because it shaves off the high frequencies and flattens the sound." When done properly this just does not happen.

I can hear it all now, HISS, HISS:sun Must be the SoCal heatwave...
 
The next time there is a discussion of whether or not to use noise reduction, maybe the question we should be asking is, "What kind of noise reduction, and, do you know how to use it properly?"
Exactly. And if part of the answer is "dbx SNR-1", run as fast and as far away as you can.

The dbx SNR-1 was produced circa 1987 and is a digital component. As such, it tortures the audio signal in three ways: ADC (analog to digital conversion), noise reduction and then DAC (digital to analog conversion).

Even if we accept that the noise reduction is "flawless" (which it is not) there is still the fact that the analog signal has gone through two steps of vintage 16-bit digital conversion. This in and of itself has compromised the integrity of the audio signal.

The noise reduction scheme employed here uses a compression/expansion technique that introduces audible artifacts and does indeed result in loss of audio information (but you are right, it's not simply shaving off high frequencies - its damage is much more sinister!)

I do agree with your point that noise reduction gets a bad rap because of people who abuse and misuse it. The right techniques in capable hands can make a world of difference, but (in my opinion) the vintage dbx SNR-1 is the wrong technique in ANY hands.
 
Yikes!:eek:

My golden years ears (vintage) don't hear anything like what you are describing. I don't hear any compression or artifacts and nothing is lost but the sound of the hiss. It's easy enough to engage and disengage the units during playback to do A/B comparisons and to me the music simply does not suffer from their use. The whispy highs of symbols crashing are still full bodied. Furthermore when viewing the signals (if you don't trust your ears) through spectrum analyzers, the music signal does not become diminished on the displays when the SNR's are engaged yet the hiss is clearly gone.

In a perfect world the bias's of the tape and the player are a perfect match and there is no hiss to begin with. The recording studios have this luxury available to them and therefore we don't hear mastertape hiss on the LP's and CD's they put out. (unless they have a royal screwup) However, the rest of us have to endure varying degrees of hiss due to varying degrees of mismatched bias's. Until I ever hear anything that does a better job at eliminating these bias noises I'm sold on what the SNR's can do. And that's my biased opinion based on what I've heard.:phones
 
Exactly. And if part of the answer is "dbx SNR-1", run as fast and as far away as you can.
You must be confusing the SNR-1 with some of the other DBX units. There is no reason to run from these beatiful little babies.

The dbx SNR-1 was produced circa 1987 and is a digital component. As such, it tortures the audio signal in three ways: ADC (analog to digital conversion), noise reduction and then DAC (digital to analog conversion).
The SNR's were released as part of the "Digital Series" put out by DBX. It was just a marketing name, the units are totally analog.

Even if we accept that the noise reduction is "flawless" (which it is not) there is still the fact that the analog signal has gone through two steps of vintage 16-bit digital conversion. This in and of itself has compromised the integrity of the audio signal.
Again, these are totally analog units. No digital conversion going on with these babies. Just pure sweet analog bliss.

The noise reduction scheme employed here uses a compression/expansion technique that introduces audible artifacts and does indeed result in loss of audio information (but you are right, it's not simply shaving off high frequencies - its damage is much more sinister!)
There is no sinister compression / expansion going on with the SNR's. It uses discrete component VCA's (voltage controlled amplifiers) to "sense" the incoming frequencies and then drives the variable frequency NR filter to ride right over the actual input frequencies. The only "control" on the SNR-1 is its transition level control.......which simply controls the sensitivity of the VCA's so that "hiss" or "noise" isn't seen as actual signal. That is where the potential for user error comes into play.

I do agree with your point that noise reduction gets a bad rap because of people who abuse and misuse it. The right techniques in capable hands can make a world of difference, but (in my opinion) the vintage dbx SNR-1 is the wrong technique in ANY hands.
I still think you must be confusing the SNR's with some of the other DBX units. DBX's "noise reduction" units (like the 224, 228, etc.) are based upon a 2-1 compression, and then 1-2 expansion.....however the SNR-1 doesn't employ that method AT ALL. As to the performance of the actual NR units based upon DBX NR....they weren't so bad either, when in capable hands. They totally dominated the market when introduced and until "digital" recording pretty much took over the market. They nearly blew Dolby out of the pro market. And I don't know what you think of "stereo" TV....but MTS stereo broadcast adopted DBX noise reduction for all commercial broadcasts (and it's still used today I think!).

So my advice is to run, don't walk, as fast as you can, towards the next SNR-1 you see and beg, borrow or steal it. Nothing beats it for removing hiss and retaining music that I am aware of.
 
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This jogged my memory!

Back in the day, I ran a DBX3 Dynamic Range Expander and pushed my Tape signal through a DBX - NX40 unit. The result was less than ideal.

Back then, you had to be careful of the products you purchased and as stated so well in this thread, "Have the working knowledge to use it properly." This is where I dropped the ball. I was young and just learning the ropes.

I later learned that there were special recordings just for the NX units. I managed to find a couple of them and there was a marked difference in the performance of the hardware.

Your points are well taken.:smokin
 
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The SNR's were released as part of the "Digital Series" put out by DBX. It was just a marketing name, the units are totally analog.
Really? That's odd. No, that's just plain misleading. I'll have to trust you on this one. I always thought they were digital.

I still think you must be confusing the SNR's with some of the other DBX units. DBX's "noise reduction" units (like the 224, 228, etc.) are based upon a 2-1 compression, and then 1-2 expansion.....however the SNR-1 doesn't employ that method AT ALL.
It is my understanding that ALL dbx noise reduction is based on a compression/expansion technique. I'll have to trust you on this one too.
 
The best recording system that I ever own was DBX TYPE-II (224X) and an AKAI 740D cassette deck. The cassette deck is no longer useable so I purchased an Nakamichi 700(1973). The combination of the 700 and DBX type II works great.
 
Hi all,
Just want to let you all know the I received my DBX SNR-1 tonight. I just play Doobie Brother albam "What Once Were Vices Are Now Habits" and it sounded fantistic. They music came out clear without any background noise. The Marantz Vari-Matrix circuit in the 4140 did a wonderful job of creating a surround sound performance :banana: of the entire record.

So what is the expected resuilt when I play my SQ encoded records though this? Will the SQA-2 actrully work better? Oh I guess I should spin one of these and find out. I have to wait till tommarrow, all of the kids are in bed.:kitty:
 
Hello all,

I too just received my DBX SNR-1 and will be getting it into the signal stream this evening. I will report back to the forum concerning all performance aspects of this unit, to the best of my ability.

MTGC (Michael)
 
Well, I have finally gotten the DBX SNR-1's connected to my "away from home" set-up. As information, my away from home set-up consist of the following equipment:
Sansui QRX 6500
Akai CR 80 D SS
Technics SL 1300 e/w AudioTechnica AT14sa
Lafayette SQ-W
(4) Dual LMT 1000 Speakers
Koss K 2-2 Headphones
And of Course, DBX SNR-1

As information, the DBX units are connected via the 4-channel tape monitor loops

So far, I am very impressed with these DBX units. I have used them with 8 track tapes, SQ and QS encoded records and FM Stereo transmissions and I can report that this unit definitely cleans up all signals passed through it.

I purposefully chose a really badly scratched recording as a test for this unit and the DBX units came through fine. It did not remove all the clicks, pops and hiss, but the improvement was very good. If the original record had been rated a 2 (very poor), then after the DBX processing, it would rate a minimum 7 (very good). As information, the record I chose was the Realistic Bach to Bernstein (CQ10873). I bought this record at a yard sale, and it appeared that it had been literally drug through the yard, but for $.10, I said, what the heck, it is worth a dime. I played the record through the SQ-W first and then through the DBX's and the rating was, as I said a 7 with the bad clicks, pops, hiss and other noise reduced or eliminated. I did not try playing the record first through the DBX's and then through the SQ-W, as I was not sure how to connect the DBX to the SQ-W.
I also used the DBX's with the CR80 and was similarly impressed. I played one of my "hissier" (is that a word?) 8 track tapes (RCA Q8 The Best Of AL Hirt
PQ8 1011) and the hiss seemed to disappear and left a very clear and beautiful tape with great separation and clean rendition.
I listen to a local FM oldies station and with the DBX units in the circuit the FM hiss seems to totally disappear and the bottom end is very quiet.
I do not have a CD-4 demodulator set up here, so no CD-4 tests were run.
In conclusion, based on very limited testing, I am absolutely impressed with the DBX's. I think I have spent a small amount of money and gotten a great equipment in return.
Again, please remember that these results are a result of "ear" feedback only. As this is my "away from home" system, I have no test gear for absolute results, so take the above report in this spirit.
As I go forward with these units I will get back to this forum with more results.

MTGC (Michael)
 
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I did not try playing the record first through the DBX and then through the SQ-W, as I was not sure how to connect the DBX to the SQ-W. MTGC (Michael)

Michael:

I have an old first generation dbx unit (Model 224). When I was playing records I always decoded them prior to sending the signal through the dbx unit.

I have no experience with the unit you have, but I believe decoding first is the way to go. If I am wrong the more knowledgeable members of this forum will correct me.

Justin
 
Justin,

Thanks for the input. I will do the research necessary to determine the hook-ups to decode first and then use the DBX.

MTGC (Michael)
 
Hi, all. A timely topic for me. I thought I'd need two SNR-1s for quad, but it seems you can use just one. Could you tell me how to hook it up? My system includes the Sansui 9001, Akai Q8 deck, Marantz CD-400 demodulator and two dbx 400s for routing (also have a secondary Q8 hooked up for tapes that my play better on the Technics) and I run a Marantz tt for CD-4 processing through the CD-400 and a Rega player (through a phono preamp then into line jacks on the back of the Sansui) for SQ, QS and stereo. If there is a way to use just one SNR-1, I'd love to hear it and if I must just use it with one component, then I may just have to try it that way, so look forward to any help you may have. Thanks in advance!
 
You need two, one for the front channels and one for the rears, connected to the processor loops of the 400 boxes. snr-1's arn't made to clean up record noise/pops, i guess they would help some but to get rid of pops/clicks some thing like a berwin, klh transient noise eliminator is better suited.
 
I must agree that the DBX units did not completely remove all clicks and pops from my test record, but they did seem to supress them. I agree with Dave that another type of noise reduction would probably be better for click and pop reduction.
As far as hook-ups I went from the QRX 6500 quad "rec" plugs to the DBX's "from tape monitor" jacks. I then went from the DBX's "to preamp"
to the QRX's tape mon jacks.

Hope this helps,

MTGC

p.s. Sorry about the misleading earlier posts that seemed to indicate I only had one DBX unit. I have never had much skill in the english language, as the above posts are just a few examples, but again, I apologize for any misleading I inadvertently did.
 
I must agree that the DBX units did not completely remove all clicks and pops from my test record, but they did seem to supress them. I agree with Dave that another type of noise reduction would probably be better for click and pop reduction.
As far as hook-ups I went from the QRX 6500 quad "rec" plugs to the DBX's "from tape monitor" jacks. I then went from the DBX's "to preamp"
to the QRX's tape mon jacks.

Hope this helps,

MTGC

p.s. Sorry about the misleading earlier posts that seemed to indicate I only had one DBX unit. I have never had much skill in the english language, as the above posts are just a few examples, but again, I apologize for any misleading I inadvertently did.

I do use my SNR-1's on bad vinyl and they really do help alot! As yet I haven't pulled the trigger on a transient noise box, I'm going to try and whittle down the big quad setup from it's current Godzilla size to a friendlier Frankinstien configuration so adding another box I have not wanted to do. I clean my records before play with a poor mans cleaning machine, the Spinclean from Garage-A-Records (about $60 as I remember).

Some time in the comming months I'm going to get out of the CD-4 biz, I just don't listen to that part of the set up anymore. So that means a rare AT SL-20A with 20 hours on the stylus will be on the market along with my super clean Sansui 3080. Probably going to quit Q-8's too, so a QB restored Technics blue meter 858. One of my Sansui quad rtr decks has got to go and, God I hate to say this but my QB restored D-1 is going to be history. :yikes
 
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