All About National Semiconductor's Dynamic Noise Reduction System

[r0natello]

To my ears, the DNR seems to somewhat dull the upper harmonics of the guitar and vibes. It got rid of the hiss though!

[Lachlant1984]

I know this isn't really too relevant to this video, but I've noticed that on my iMac there's an Ambient Noise Reduction feature that works with the internal microphone, I've played with it a little bit but not extensively and it certainly works from the very short tests I've done, I'm not sure if it introduces negatively desired artefacts or not, but I'm not willing to really use it if it does.

[dogwomble]

DBX was not popular on _consumer_ tape equipment. However, it was extremely common on multi-track cassette systems, examples the Tascam and Yamaha 4- and 8-track recording decks.

[Matthew55904]

i odnt see a difference i can still hear what sounds like rain on both only different is there is no hiss but the rain sound dont change and what are metal tapes? they actually contain metal?

[uxwbill]

@Matthew55904 Hm. Another comment that was never brought to my attention. The rain sound belongs there and is a desired part of the recording. The hiss is not a desired part of the recording, and its absence is what you are supposed to notice. So you are on the right track.

All tapes contain "metal" (usually ferric oxide in a normal bias tape). Tapes advertised as "metal", "CrO2" or "high bias" used different metals in different formulations to produce a cleaner sound with less hiss and noise.

[The18Jake]

I have my old radio unit out of my 1984 lincoln town car. It has two buttons. One is the Dolby NR, and another that says CrO2,which I have no clue as to what it does.

[uxwbill]

@The18Jake The CrO2 button allows you to play high-bias (Type II) cassette tapes with the proper equalization settings. In some cases, it may also work to play Type IV "metal" tapes. There will not be any harm done by not enabling this button, although the sound from the tape might not be good if you are playing tapes of that kind. Such tapes are usually labeled on their casing, so you'll know what to do if you see one.

[Lachlant1984]

It's not often that you see a car stereo where you insert the cassette in open end first, most car radios I've seen with a tape deck require you to insert the tape with the open end facing to the right. 

[OKnight1Roger]

where did yu getthat deice sterio?

[uxwbill]

@OKnight1Roger It came from the silver 88 Buick. It needs a capacitor job at the very least. I'm waiting on parts.

[Matthew55904]

@uxwbill u should do what ive seen to other GM Stereos like that on ebay wire a AUX in jack to it that cuts radio signal when used so ur brother can play say a iPhone on it

[GROUCHYDEVIL]

i like your technics turntable above your tape deck ;O)

[Fuzy2K]

28:48 -- I don't get it; What -did- you do there?

[uxwbill]

@Fuzy2K It's very subtle. I swapped the position of the Archer sound processor and the DNR System 911 unit.

It wasn't intentional. I added the annotation later, after noticing what I'd done, just to see who might pick up on it. :-)

[blazerlover25]

well this is quite the surprise..a G rated video from uxwbill at least we aint watching uxwbill get it "up" lol ( my eyes are still hurting from laughing over that video)

[vwestlife]

You forgot one other reasonably widespread pre-encoded noise reduction system: CBS Labs' "CX" (Compatible eXpansion), used on the analog audio tracks of LaserDiscs and CEDs, as well as on a small number of LPs (around the same time DBX-encoded LPs were being released), and on the unsuccessful "FMX" FM Stereo noise reduction system in the late '80s. CX was also proposed as the noise reduction system for stereo TV broadcasts, but the FCC ultimately chose a different system using DBX.

[uxwbill]

@vwestlife I'd forgotten about the CX system, although "FMX" is a new one on me. I only knew of Dolby FM from the 1970s...

[rmx77]

i happen to have come up with a pioneer ct-w404r that has b, c and hx-pro. i like the deck and i got it from the original owner with original box and manual. i wonder about hx-pro and what your thoughts are bout it

[uxwbill]

@rmx77 Dolby HX ("Headroom Extension") Pro isn't really a noise reduction system. It's a system that works with the biasing circuit in a cassette deck when recording and can let you drive the recording levels higher than a machine without HX Pro could. When recording to tape, I am usually conservative in setting the recording levels.

[rmx77]

@uxwbill well in my collection of tapes i happen to have found a tape that was recorded in dolby b hx pro how rare can that be. well glad i have the recorder for it. also i am on a hunt to find some super high quality professional or broadcast tape if u know of any to look for

[uxwbill]

@rmx77 Tapes encoded using Dolby B and the HX Pro system are not uncommon. There was a lot of support for the HX Pro system in later model tape decks. It only comes into effect when you are recording. Any cassette playback machine, whether it has HX Pro circuitry or not, will work perfectly to play back a tape made on an HX Pro-equipped machine.

[ianhawdon]

I'm not really a fan of this system upon hearing the demos, as @THEtechknight said, it seems to cut the highs just a little too much for my liking. I much prefer using Dolby B on a well cared for tape deck and tapes. Head alignment adjustment can really bring out those high ends when the Dolby switch is on. I am noticing that a lot of my tapes have been recorded with the heads aligned slightly differently, so when transferring to FLACs, I usually adjust the heads for optimal sound on each side.

[uxwbill]

@ianhawdon That could be mitigated by turning the "enhancement" setting to "high", or even dialing the sensitivity to a point where it isn't as aggressive. I wanted the effect to be clear and noticeable, so I got a little heavy-handed with it. The Radio Shack device preserves more of the high end than the DNR System 911, although it has fewer adjustments (sensitivity only).

I also wonder if that "high loss" is another trick of perception, that the reduction of hiss makes the highs seem duller..

[BadEditPro]

Cool Video! DBX was very popular in recording studios and some radio stations for use with on-air cart machines. VHS Hi-Fi actually modulates the audio as FM and records two carriers for each channel on the tape behind the video signal. The audio is encoded with a DBX like NR in VHS Hi-Fi, too. It also lays down a standard linear signal for VCR's without Hi-Fi. :) JC

[andrewcrawfor1381]

the accustic function on the delco radio DNR was from what a teacher told me is the same princaple that if u had a suround sound system if u put the speakers in an X pattern you have a hard time pin point the source least thats what i believe

[NJRoadfan]

Heh, I got a silver Technics deck (RS-M14) very similar to that one, slightly older. The only difference is it has a tape bias/type dial since it lacks auto detect and the record level dial is combined into one (still stereo). Dolby was popular in dual linear track SVHS editors. Marantz even released a linear stereo Betamax (made by Sanyo) with Dolby C! DNR is nice, but today's computer software can do the job and is tweakable. Tapes typically just need a low pass and some adaptive NR for dehiss

[uxwbill]

@NJRoadfan The RS-M14 is an *excellent* deck. My dad bought one brand new in the early 80s and it is still here. It supports the unsuccessful Type III tape formulation, which seems odd considering how new it is. The record level knob is actually two halves, although it works like one if the glue fails on the outer knob. :-)

I like listening to and making mix tapes of my own, mainly because it's so easy to play a wide variety of sources into my stereo. So noise reduction still has a place here.

[THEtechknight]

only bad thing is, it cuts the highs quite a bit. which is why i never liked dolby either. Well, at least with my ears i can tell the difference night and day. The hiss is gone, but the highs are gone too :-(

[THEtechknight]

theres one problem with modifying the delco radios, all the IC's are in-house part numbers so your kinda screwed there as far as modifications go, as you dont know what the ICs are.

[uxwbill]

@THEtechknight I remember finding that out for the first time when I popped the cover on my 2003 S-10 radio to see what was in there. But I did manage to figure out exactly what each part was, with the exception of one device I just couldn't cross reference.

I'd love to know the capabilities of the microcontroller they used. It's identified as an "H60 Flash" and is used in simple Delco AM/FM sets, CD players, CD/tape combos and a unit that plays MP3s from CD.

[THEtechknight]

@uxwbill Its probably an 8051 variant, which seems to be the norm for 8-bit mass production these days, but then again I cannot rule out the 68HC10 line because the older car computers used this MCU for its operations. Hard to say?

[bratina501]

I actually have seen a Delco car radio with automatic DNR in person. Believe it or not they actually made a radio with BOTH DNR and AM stereo in the form of the UX-1 which has a five band graphic equalizer and an Am-St button. This one can be found in many GM vehicles especially Cadillacs.

[SwingMan1937]

From my experience in recording since the 1980's, all DNR tends to do is deaden the impact & crispness - takes the sharpness, detail and ambience right out. It's good for electronic music which doesn't depend on acoustics for body and impact, but for live recordings, IMO, forget it.

My experience with dbx is mixed - I used dbx technology in production back in the 1990's and, while it does silence very well, it also compresses and flattens everything out, eliminating virtually all headroom.

[uxwbill]

@SwingMan1937 I suppose it's all in the hearing of the beholder. :-) I've played mostly studio-recorded music into the DNR system and the results have been good to my perception. It didn't do so well on a studio-recorded album with lots of strings and a very wide dynamic range...keeping the strings from getting squashed meant leaving the filter open to the point where hiss was essentially unfiltered.

I'll have to throw a live album at it and see!

[SwingMan1937]

@uxwbill Yeah, I'm referring mostly to live recordings (studio as well as stage). Great for electronic music, not so great for live/miced stuff.

[uxwbill]

@bratina501 If it's decoding C-QuAM AM stereo, it's not giving anything away. I don't hear any separation on known AM stereo broadcasts and the stereo indicator only turns on when playing FM stereo broadcasts. (It must be said that the FM stereo separation in the pictured set is nothing less than stunning with good input.)

[bratina501]

@uxwbill I actually was wrong about that having AM stereo reception, my mistake. There is one I know that has DNR actually AUTOMATIC DNR and AM stereo which is the UX-1 that can be found in many vehicles such as Cadillacs.

[vwestlife]

Since you're left handed, you can try holding the camcorder in the palm of your left hand, and see if you have less tendency to shake that way. Wrap your fingers around the bottom of the tape compartment and brace your thumb in the upper left corner of the LCD cavity, above the speaker. The only downside is that the zoom and start/stop controls aren't at fingertip reach, unless you use your right hand to operate them.

[raymondleeleggs]

I have a KLH Transient Noise eliminator.

[pskittle488]

21:01, There he goes breaking the 4th wall rule, LOL.

I think you told us more than any of us realized we wanted to know, very informative, LOL.

[uxwbill]

@pskittle488 I have a lot of fun with that, as well as the concept of alter egos. I suppose that may indicate some kind of complicated-sounding illness... ;-)

[CenTexVideo]

The only real issue with camera shake, especially if it's excessive, is the variable bit rate and slow internet connections. This video though, played perfectly and the shake isn't as bad as you think. I know all about that. ;-)

For me at least, using stabilization requires a lot more time than I have, more CPU and higher quality video than I currently can edit.

As soon as I get a soldering iron and fix the 5000X, I can use my JVC dual cassette deck and play with the NR on that one.

Thx Bill

[Lachlant1984]

This video is very technical, I would say geeky, but I hate the word geek because it has such negative connotations. You talk about our hearing being amazing and being able to filter out unwanted sounds, I'm Autistic and I cannot filter out unwanted sounds, if I'm in a crowded area listening to a conversation, I have trouble focusing on the conversation due to excessive background noise, I find this particularly trying in restaurants etc.

[uxwbill]

@Lachlant1984 You can say geeky if you'd like. I've heard far worse. Nothing can really get you down like the things that really stupid people do and say. Sometimes it's enough to make you want to lose all faith in humanity.

I can understand what you are saying about the whole hearing and filtering thing. I didn't have it at all when I was younger. Like every other milestone, it came to me later in life than most of those around me. I am guilty of stating an "average" capability here tho! :-)

[vwestlife]

Some aftermarket car radios had DNR too. I had a similar Realistic video sound processor and wasn't too impressed with any of its features (the "stereo synthesizer" just applies different EQ curves to each channel). Its "surround" decoder is probably just a simple matrix-type quadraphonic decoder, since the Dolby Pro Logic decoder wasn't invented until 1987, and Dolby Surround didn't provide discrete L & R rear channel outputs until Dolby Pro Logic II was introduced in 2000.

[uxwbill]

@vwestlife I don't know about the stereo synthesizer in this unit, what it's doing sounds just plain wrong. The information I have on Dolby Pro-Logic could well be wrong...I had some information saying that it had been developed in the early 1980s.

I did kind of like the stereo expander effect, although it is not as sophisticated as the one in my newer Optimus equalizer.

Performance of the DNR system in both devices is almost identical, with the exception of the "enhancement" function.

[vwestlife]

@uxwbill Dolby Surround (the encoding format) was introduced in 1982, but the Pro Logic (the decoder circuitry), which provides a front center channel and front-to-rear "steering" to improve the surround effect, wasn't introduced until 1987, at least according to Wikipedia. The various matrixed quadraphonic systems in the '70s also utilized logic-driven steering circuits to improve the rear channel decoding, although this was only found on fancy high-end receivers, such as the Sansui QRX series.

[uxwbill]

@vwestlife Maybe that's what I'm really thinking of and meant to say. It's hard to tell sometimes. :-)

Something I want to try...there is an alleged quadraphonic broadcast done over a C-QuAM stereo broadcast on the Meduci site. I plan to play it through the Archer box and see what happens...good or bad, it could be interesting! It does have some simple logic around the "surround" parts (a quad bilateral switch at least), although I haven't traced it out to see exactly how it's used...

[vwestlife]

@uxwbill I have the SQ Quad mix of Santana's "Oye Como Va" on my vwest1ife channel if you want to give it a try. Recordings mastered using the Bedini Audio Spacial Environment (B.A.S.E.) and "QSound" will also give very noticeable rear channel effects from a matrix-type decoder. Suzy Bogguss and some other Country artists used B.A.S.E. on their albums in the late '80s and early '90s, and QSound was used around that time by artists like Madonna, Sting, Roger Waters, and Janet Jackson.

[uxwbill]

@vwestlife I'll definitely try that. I have at least one CD of "nature music" that claims to use QSound. IBM's Audiovation/Mwave sound card also has the option to enable QSound on its line output for all sources (though it usually can't load the MIDI software onto the DSP when QSound is enabled, since it takes up lots of DSP memory).

[Lachlant1984]

@vwestlife I think Dolby Pro Logic II was introduced a bit earlier than 2000, like 1998 or something because I have Donkey Kong 64 which came out in 1999, and I'm pretties sure that game utilises Dolby Pro Logic II as a lot of video games do these days, I've not tried it because I don't have anything that can decode Dolby Pro Logic II.

[dana44s]

Very nice video Bill! I've been curious about these systems. Also; What's the name of the song you use? It sounds cool.

[uxwbill]

@dana44s It's a song from a NatureQuest tape. The tape is downstairs right now. I will get it later and post that information.

[dana44s]

@uxwbill

Thanks. Unless I missed something, I never saw said information. No rush though!

[uxwbill]

@dana44s You didn't miss anything. :-) I'm a lazy-butt at times and haven't been downstairs long enough to grab the tape...guess I'd better do that!

[destroyersoueu]

High Com was able to remove noise from the tape and also noise was coming into the audio program too...unbeatable in the past...High Compander (compressor and expander)

[destroyersoueu]

About the new ones... created after 1990 i do not know the ones are good or bad..and if they are better or worse while comparing with ADRESS and High Com

[destroyersoueu]

I had all types...i have 60 years old... better is High Com from Telefunken and second is ADRESS from Toshiba...dolby is nice but weak in reduction of noise...these other two kills noise totally..you can increase volume all the way up and you will use no noise...my hobby from 1960 to 1990 was to adjust, calibrate, cassete and open reel decks

[vwestlife]

Dolby S sounds to my ears like a combination of Dolby B and a wideband compressor/expander. So playing back a Dolby S recording on a deck with Dolby B decoding, or even no Dolby at all, will generally sound OK, except that the dynamic range will be compressed, as if the music was being played by a highly processed FM radio station. It does not apply a drastic EQ curve to the audio like DBX does. And yes, you can use Dolby S on a Type I tape.

[bbdln847]

my dads 92 gmc sierra had that same radio as the key keepers truck and the DNR Feature is not supposed to come on on the display it actually is a automatic feature on the radio and cassette. It was printed on the display as an idea but after it had been printed the whole automatic feature was implemented so a button and indication for it working was not needed! cool video uxwbill

[uxwbill]

@bbdln847 Interesting to know. It would still be nice to know when the system is active, if for nothing other than sheer blinkenlights effect. The tape deck in the Keykeeper's truck says on the tape door that it has "Auto Dolby Noise Reduction". I wonder if that's really true, or if the Dolby decoder is simply on all of the time? I can think of some ways to "test" for Dolby noise reduction, but none that are foolproof and you'd need some kind of a "latch" to prevent "bouncing" the circuit.

[margaretsville]

Type II and type IV tapes have about the same noise level. The difference is that the type IV will allow you to record a higher signal, thus creating a de-facto lower audible noise. But a blank type II and a blank type IV played one after the other with the volume turned all the way up should have very similar noise characteristics.

[uxwbill]

@margaretsville I'd like to get some more Type IV tapes to work with, as my experience base is very limited. The Sony tape is basically dead silent. I couldn't perceive any noise from it, not even when recording only the bias signal to it. Informally, I'd say my hearing still runs out to around 19kHz or so.

I did notice a more profound difference between Type II tapes. Those Fujifilm tapes are *excellent* compared to most others...very quiet, rich sound and nearly no dropouts.

[steve062989]

Not to be a smarty mouth or anything but have you considered a monopod? the camera shake isn't that bad but it could help. still enjoy all your videos.

[uxwbill]

@steve062989 I have one somewhere. It's a combination walking stick and monopod. I have never tried it.

[Fuzy2K]

What was the song you used at the end of the video? It sounded pretty cool!

[weasel2htm]

@Fuzy2K Agreed, I'm curious too. BTW, I hope uxwbill can get his hands on a dolby S deck in the future so he can play with it.

[uxwbill]

@weasel2htm @Fuzy2k The song is from a NatureQuest cassette tape. I still haven't been downstairs to retrieve it and get the exact title.

[269VaneM]

Does iMovie HD ('06) have an image stabilization system? Not that I am trying to bring up the shake–I'm not. I just seem to remember something about a stabilization system in that revision of iMovie..

[uxwbill]

@269VaneM I think it does--or that Quicktime has an optional filter module I could use when exporting--but I'd confess that I have not tinkered with either option.