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View Full Version : [Help Needed] What does this do? DBX 4BX



nguyendot
05-06-2010, 10:19 PM
Picked this thing up at Goodwill one day on a hunch. I have no idea what it does. Hooked it up like an equalizer to play with it, and it seems to do what a compressor does.

Worth anything?

http://i55.photobucket.com/albums/g150/nguyendot/Craigslist/DSC_0058.jpg

Yes those are my stinky feet.

hoosier21
05-06-2010, 10:46 PM
I would buy it, how much you want? did you get the remote with it?

FTGV
05-06-2010, 10:59 PM
.... it seems to do what a compressor does.

It does the opposite,its a 3 band dynamic range expander.

nguyendot
05-07-2010, 12:00 AM
No I couldn't find the remote. Oh well.

concealer404
05-07-2010, 10:06 AM
It makes pretty lights. :D

jm1
05-07-2010, 11:16 AM
I lifted this from another post of mine and slightly edited it.


Dynamic range is the difference in volume, measured in dB, between the loudest and softest passages in music. Recording studio engineers used to compress the dynamic range of music (literally squeeze it onto a record or tape) to fit the limitations of those media. Dynamic range expanders increase the dynamic range of any source.

DBX 3BXIII

It divides the audio frequencies into three ranges (HF, MF, LF) and handles each separately. The unit lets you choose how much expansion you desire, the transition level and the threshold at which the upward and downward expansion occures. In addition, the unit restores the impact (impact restoration - reconstructs the initial transient of a note) of a live performance that is lost during mixing. The range is 0 to 12 dB.

Even though we have moved forward with media capable of greater dynamic range, we appeared to have taken a giant leap forward with the amount of compression applied. I would keep this. I have my 3BXIII from the mid 80's and will never sell it.

snow
05-07-2010, 11:24 AM
It is probally a $200.00 item on Ebay so it is worth something yes :)



REGARDS SNOW

nguyendot
05-07-2010, 11:35 AM
lol. I dont really need it. It's another one of my 'buy and flip' items. This month has been doing very well. For $200 i'd hock it immediately. It's cool, and the lights move in a 1980's fashion which is neat, but the effect is lost on me.

I prefer to run the signal straight to my amp.

hearingimpared
05-07-2010, 12:19 PM
Great piece! Wonderful for noise reduction on cassette and R2R tape players. I wish I could afford to buy one to upgrade the 224x that SNOW so graciously sent me.

hearingimpared
05-07-2010, 12:22 PM
It is probally a $200.00 item on Ebay so it is worth something yes :)



REGARDS SNOW

Hmmm . . . I would think it would go for more than that Dan. I've seen 224x's go for close to that amount. A year or two ago I (regrettably) sold my 224x I had been holding onto for IIRC $165.

jm1
05-07-2010, 01:23 PM
FYI

The 4BX is NOT a tape noise reduction unit like the dbx Type I (professional) or Type II (commercial eg. 224x) units. The 4BX can be used to improve any line level signal; FM, tape, LP, CD, other digital etc.

If I had a monitor loop on my current preamp, I would still have mine connected for use when desired or needed.

nguyendot
05-07-2010, 02:09 PM
I saw it sell for 400-500 on other sites. Im not looking for remotely that lol. I could care less if I sell it, I just do this stuff for fun, like Tony Millard :)

ESavinon
05-07-2010, 02:35 PM
It's a dynamic range limiter/expander. It's worth at least $400 without the remote.
Great find. I't excellent for analog/vinyl use.

nguyendot
05-07-2010, 02:44 PM
I guess I can use it with the turntable, but lately i've been on a craigslist binge.

Talk about a secondary income!:D

This unit was marked $3 or $5 (can't remember) at the local Goodwill.

ESavinon
05-07-2010, 02:54 PM
:eek::eek::eek: $3-5.00 :eek::eek::eek:
Try it. You'll keep it once you learn how to use it.

If you're patient and plan on keeping it, I can send you a copy of the owner's manual. I need to dig it out of storage.

nguyendot
05-07-2010, 03:34 PM
I found the manual, apparently dbx still has it online.

I used it last night with some streaming music. Very interesting effect. I liked it, but still I prefer a straight signal to my amp.

Currently clearing out ALL of my equipment, going to wipe the slate, start clean, and get rid of all the Goodwill finds.

hearingimpared
05-07-2010, 04:16 PM
FYI

The 4BX is NOT a tape noise reduction unit like the dbx Type I (professional) or Type II (commercial eg. 224x) units. The 4BX can be used to improve any line level signal; FM, tape, LP, CD, other digital etc.

If I had a monitor loop on my current preamp, I would still have mine connected for use when desired or needed.

I didn't know that. Better still!. I like those types of toys.

Thanks for the info John.

jm1
05-07-2010, 04:57 PM
I found the manual, apparently dbx still has it online.

I used it last night with some streaming music. Very interesting effect. I liked it, but still I prefer a straight signal to my amp.

Currently clearing out ALL of my equipment, going to wipe the slate, start clean, and get rid of all the Goodwill finds.

This would be a keeper regardless what you could get on the open market, but that is my opinion.


FWIW, based on your picture, you do not have the unit properly configured.

Set the transition level so the bands (esp. the HF band) are equally adding (red) and subtracting (orange) from the signal. This way you are adding to the peaks and subtracting from the quieter to extend the dynamic range. All the people I have known have the unit always adding to the signal like the picture; this is not what the unit was designed for nor does it sound very good. I always found having about 20 - 30% expansion level was appropriate regardless of source.

I usually set the impact restoration at about the same level. There should also be a release rate on the back of the unit to set how fast the transient is released.

John30_30
05-07-2010, 04:58 PM
I found the manual, apparently dbx still has it online.

I used it last night with some streaming music. Very interesting effect. I liked it, but still I prefer a straight signal to my amp.

Currently clearing out ALL of my equipment, going to wipe the slate, start clean, and get rid of all the Goodwill finds.

How much would you want to flip it for if I came by your house to pickup? I like to transfer rare cassettes sometimes.

hearingimpared
05-07-2010, 05:04 PM
How much would you want to flip it for if I came by your house to pickup? I like to transfer rare cassettes sometimes.

John I think you need to look for a dbx 224x as JM1 noted the above unit isn't for tape noise reduction but I can vouch for the 224x, it is awesome and is way better than anything that Dolby use to put out. I still have some dbx encoded tapes that I made way back when. Unfortunately I gave my dbx encoded LPs to the fella who bought my original 224x.:mad:

John30_30
05-07-2010, 05:21 PM
John I think you need to look for a dbx 224x as JM1 noted the above unit isn't for tape noise reduction but I can vouch for the 224x, it is awesome and is way better than anything that Dolby use to put out. I still have some dbx encoded tapes that I made way back when. Unfortunately I gave my dbx encoded LPs to the fella who bought my original 224x.:mad:

Now you guys are confusing me. :confused: I thought it basically improves and expands the signal? I can use software to reduce noise, if need be.

That's assuming nguyendot wants to get rid of it.

hearingimpared
05-07-2010, 05:28 PM
Now you guys are confusing me. :confused: I thought it basically improves and expands the signal? I can use software to reduce noise, if need be.

That's assuming nguyendot wants to get rid of it.

Whoops, I'm the one who was confused John not you. I just reread your post and realized it was for transferring the cassettes to CD, right? DUH . . . sorry about that bro.:o

nguyendot
05-07-2010, 10:02 PM
How much would you want to flip it for if I came by your house to pickup? I like to transfer rare cassettes sometimes.

Honestly don't know. Wasn't planning on hocking it on the forums lol. It's on the local CL however if you want, along with all the other stuff im trying to get rid of.

jm1
05-07-2010, 10:28 PM
Based on your original post in this thread, I had no idea you had this much experience with the dbx units:


Absolutely magic! I have used dbx 3BX expanders in all my commercial installations, and in my home system since 1978!

Edit: Sorry, my mistake. The person who wrote the information might have had this much experience with the units.

John30_30
05-07-2010, 10:36 PM
Honestly don't know. Wasn't planning on hocking it on the forums lol. It's on the local CL however if you want, along with all the other stuff im trying to get rid of.

I don't need it that bad.

snow
05-07-2010, 10:49 PM
Hmmm . . . I would think it would go for more than that Dan. I've seen 224x's go for close to that amount. A year or two ago I (regrettably) sold my 224x I had been holding onto for IIRC $165.You would think :) I am sure that there has been some that have sold for morei n the $300-$400 range but at least recently on Ebay they have sold for less, here are the last couple completed auctions.

http://cgi.ebay.com/DBX-4BX-Three-Band-Dynamic-Range-Expander-/200464551334?cmd=ViewItem&pt=LH_DefaultDomain_0&hash=item2eac9e4da6

http://cgi.ebay.com/dbx-4bx-Three-Band-dynamic-Range-Expander-/200465042173?cmd=ViewItem&pt=LH_DefaultDomain_0&hash=item2eaca5cafd

REGARDS SNOW

Polkie2009
05-07-2010, 11:24 PM
Talk about a blast from the past.... I still have my old DBX 224 unit I bought from Sheffield Audio in Houston and used it to play DBX vinyl records.