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#984655 - 06/15/10 02:31 PM RDAC is definetly lossy
DesordenJuanra Offline
Space Cadet


Registered: 05/23/08
Posts: 8
Loc: Barcelona, Catalonia, Spain
Hi folks,

i' ve been reading a lot about the lossless or lossy capabilities of the Roland RDAC codec, and have found that some have experimented with pink noise to determine if its or not a lossy format. So I decided to make a diffent experiment.

Using my VS-840GX I have recorded a wave in different RDAC formats inside the Roland while mirroring the signal by the VS coaxial digital out to digital input in my Digidesign MBOX + iMac in uncompressed wav. I have used Ableton Live to reproduce the original wave and to record the mirrored signal, all sinchronized via MIDI. Then I have passed the sound recorded inside the roland to my iMac by the coaxial digital output into another Ableton Live track. Then I have inverted the RDAC track, and mix them (we substract the RDAC and the wav signals). If the waves were identical, that is "if RDAC were a lossless format", the result would be a zero signal, BUT IS NOT.

Listening and mettering of the resulting wave shows some distorted original signal, wich means noise in the RDAC recorded sound, proporcional to the amplitude of the original waves. It' s shown too how this noise varies with the different recording formats.

I have used the song "Pigs on the wind" by Pink Floyd to make the test, with a top of 14-18dB RMS (4-8dB PEAK), and I found the next noise results for every recording format:

MT1: noise top 75dB RMS (59dB PEAK)
MT2: noise top 57dB RMS (46dB PEAK)
LV1: noise top 51dB RMS (41dB PEAK)
LV2: noise top 50dB RMS (34dB PEAK)

As Roland informed us, MT1 is the best format and LV2 the worst, and all of them are lossless. The test signal where recorded at 44100Hz 16 bit.

I love the Roland sound and I compare the MT1 75dB with the best vintage cassette tape recording quality, so I will continue recording in my VS-840GX for many years!!
_________________________
Desorden Juanra
http://www.desordenjuanra.es

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#984658 - 06/15/10 02:55 PM Re: RDAC is definetly lossy [Re: DesordenJuanra]
Maps and Guitars Offline
Planeteer


Registered: 10/28/04
Posts: 692
Loc: New York City
Oh, the Roland's definitely a mid-fi box, no doubt about it. I'm perfectly happy with the results myself, though: I'm comparing it with cassette as well! And anyhow I don't think that any of what I do would really be improved much by higher fidelity.
_________________________
The James Rocket: Because nobody's gonna hear it if it stays in a shoebox. www.thejamesrocket.com

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#1831078 - 01/22/23 01:40 PM Re: RDAC is definetly lossy [Re: DesordenJuanra]
guraknugen Offline
Planeteer


Registered: 10/04/02
Posts: 800
Loc: Norsborg (too far from Götebor...
 Originally Posted By: DesordenJuanra
As Roland informed us, MT1 is the best format and LV2 the worst, and all of them are lossless. The test signal where recorded at 44100Hz 16 bit.


I have never seen anyone claiming they are lossless, and they are obviously not. If you use LV2 you can clearly hear the loss. Also, if they all were lossless, only LV2 would be needed and the other formats wouldn't exist at all, since they all would sound exactly the same (otherwise they are not lossless).

Yes, I know this thread is almost thirteen years old, I just couldn't resist… 😁
_________________________
Johnny Rosenberg (Andersson until 2007-07-31)
VS-2480HD (2001-09-25 – ∞)
VS-880VX (1996-03-27 – 2001-09-25)

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