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External A/D Converters. Improve XT20?

Discussion in 'Converters & Interfaces' started by woods, Nov 28, 2002.

  1. woods

    woods Guest

    What audible difference is heard with quality A/D converters over the ones in the XT20?
    Are there other reasons one would want to go with external converters in conjunction with an Alesis XT20?

    What would be a good choice for converters to use with the XT20?

    Ciao,

    Woods
     
  2. Kurt Foster

    Kurt Foster Distinguished Member

    Joined:
    Jul 2, 2002
    Location:
    77 Sunset Lane.
    Woods,
    It isn't really cost effective to do this. For example an Apogee AD8000 retails for $7999. Quite expensive. Knowing what I know, about what you are trying to do, I would say that for you, going with the converters in your ADAT should serve you just fine. I bet you read the earlier posts regarding the Aardvark converters / clocks. If your going to get into all that let's start talking about getting you into a portable DAW rig. Hope that helps, I know sometimes these aren't the answers you would like to hear but all I can do is give you the true facts as I see them. Hope this helps ....... Fats
     
  3. woods

    woods Guest

    Thanks Fats,

    It's really just a curiosity at this point. but you raise a question for me. Would the recording quality with a DAW be noticeably improved?

    Also, what recording quality increase would be observed if using the external A/D converters?

    And maybe it would be worth getting a single channel or stereo converter for doing the vocal track or any overdubs?

    Thanks,

    Woods
     
  4. Kurt Foster

    Kurt Foster Distinguished Member

    Joined:
    Jul 2, 2002
    Location:
    77 Sunset Lane.
    Woods,
    Yes, recording in a DAW, provided it has adequate processing power, would yield a substantially better recording due to the fact that ADAT's highest bit rate is 20 bits at 48 k sample rate, while many DAW's are 24 bits at 48 /96 or even 192 sample rate. Also with a DAW you get to choose your interface and converters and if you want to spend the money (which I don't recommend) you can get some outrageously great converters. I think this would be overkill for you at this point however. Perhaps later…But a DAW with some decent interface / converters would serve you well.
    Not to mention you get at least 32 tracks, unlimited virtual tracks, a lot of reverbs, gates, compressors and eq's, editing abilities, and the list goes on and on. This is what I was trying to explain to you when you came to RO with your first questions.... ADAT is an obsolete technology and there is a lot of stuff out there that sounds waaaaay better! Plus ADATs are notorious for their transport problems! They are rather difficult to keep running. I don't know of any ADAT with any real use on it that hasn't been in the repair shop a number of times. If you want a portable rig you might check into a Pro Tools Digi 001 and a Pentium 4 Firewire capable laptop with the Glyph Firewire hard drive. While this isn't the only solution it is probably one of the most portable. I'm not a fan of Pro Tools but for what you want to accomplish PT may be a good way to approach it. If you were to use external converters with an ADAT the quality would be markedly improved, due to better clocking and, as pointed out previously, better filters. But you would still be limited to a 20 bit recording, the increase in quality would not be as great as if you were to go with a DAW running at 24 bits. ……. Fats
     
  5. woods

    woods Guest

    The ADAT is really just a dummy for me right now. When I got it in September it was just to keep a space warm. My first choice was the HD24 or the Tascam 24 track machine, but the cost was a little too much considering that I was wanting to begin purchasing everything else at the same time. So I got the ADAT to build around and play with. Early in the new year there will be 24 tracks sitting in its place.

    BUT ENOUGH of the blabber. My question is this: Could you give me an idea of the difference in sound that I would hear between a recording done on ADAT versus DAW or even the HD24? Is it clearer, cleaner, more highs or lows or something else?

    Ciao,

    Woods
     
  6. Kurt Foster

    Kurt Foster Distinguished Member

    Joined:
    Jul 2, 2002
    Location:
    77 Sunset Lane.
    Woods,
    The bit rate (16/20/24) affects the richness of the sound. I find 24 bit to be a fuller, more solid sound as opposed to 20 or 16 bit. Bass sounds better although you don't get better bass response. It just has more "girth" and sounds more solid. The sample rate is what affects the frequency response. A 48k sample rate puts a limit of about 22K on the highs. When you go to a 96K system you will be flat out to about 48K. A big difference in "openness" and "air". 96K also offers a better stereo image and depth. 96 K however requires more HD storage and RAM to run on a computer. I recommend going with a 24/48 system at the moment. All this PCM technology is going to be obsolete within a year or two at best. Don't waste a lot of money on it. ...... Fats.
     
  7. audiowkstation

    audiowkstation Active Member

    Joined:
    Jun 29, 2001
    Let me know if you want to sell it..I got an extra space begging for an XT20 as we speak.

    Actually, you can make them work quite well. Many hits were done on the black face 16 bit units..but really fats is right. 32 and 24 bit are about the same in sound q so 24 is good 'nuff.

    24/192K and 32/384K (vid archetecture adapted for audio use...(not avalible comercially yet)) are almost inditinguishable except you now have thousants of a dB resolution with the latter.
     
  8. Kurt Foster

    Kurt Foster Distinguished Member

    Joined:
    Jul 2, 2002
    Location:
    77 Sunset Lane.
    I've still got a stack o' blackfaces....I'm hanging on to them until someone decides that they were the best thing ever..."you know the Blackfaces sounded better,....'cause they're black" like 1176's and LA4's...... :D Fats
     
  9. audiowkstation

    audiowkstation Active Member

    Joined:
    Jun 29, 2001
    I have a dirty trick for the blackfaces (with evil grin on my face)

    As a tweaker, I managed to replace a ton of components in them and turn the tape much faster..(t-200=33 mins) but it cost too much to do that now.

    If you ever have one die, I am the power supply King with them. No spares, but I can fix them.
     
  10. Kurt Foster

    Kurt Foster Distinguished Member

    Joined:
    Jul 2, 2002
    Location:
    77 Sunset Lane.
    Bill,
    What was the advantage of turning the tape faster? Did it up the sample rate? It's not as if more tape surface would improve the sound...or was it a tape durability issue? My machines used to just chew through the tape after 20 or so hours. I was making more back ups that music...gawd I hate ADATS! .......... Fats
     
  11. woods

    woods Guest

    Bill and Fats,

    have you had any experience with the Aphex 1100 preamp with the built in ADC's? I wonder if they might improve on the ADAT's ADC's? Or in the future the HD24's ADC's?

    Also, when using external ADC's with an XT20, how does it work in general - for instance - are the XT20's ADC's somehow bypassed or shut off or what?

    Following is a little blurb on the Aphex 1100.

    Superior Digital Audio The 96KHz/24-Bit A/D Converter The Model 1100 includes a full spec Analog-to-Digital Converter using Aphex patented d.c.cancellation servo technology for maximizing the dynamic range of digital recording. The Aphex designed interface allows you to freely sync the digital clock internally or from external sources. The external clock mode automatically detects and locks to standard "Word Clock" and without audio data). Clock sourcing,locking,and pass through options allow for virtually any studio clocking scheme of individual or multiple units. Digital conversion accuracy is guaranteed by precisely matching the digital dynamic range to the mic preamp's dynamic range. Quantizing distortion is thusly minimized and maximum possible digital audio quality is easily maintained at all times. You cannot find a better A/D conversion platform for microphones.

    Ciao, woods
     
  12. Kurt Foster

    Kurt Foster Distinguished Member

    Joined:
    Jul 2, 2002
    Location:
    77 Sunset Lane.
    Woods,
    The A to D on a HD24 really isn't all that bad. It's the 16 and 20 bit tape machines that are weak in this department. The Aphex is a good mic pre (not the best but good). I advise people not to get these all in one box's because once the converters become obsolete, and they will, your stuck with them and you just have to out and buy stand alones anyway. Save your money, what your doing is fine, I wouldn't be thinking about investing in high end converters at this time, the marketplace is very volatile. Right now, it's a good time to just sit and wait. Fats
     

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