USB input

Hello,

Tried my USB input for the 1st time last weekend and was wondering about others experience with it. I hooked up my few year old Dell laptop USB 1.1 and RR2150 started to hum. Played a few songs to make sure it did work and it did, but the hum persisted. Even when I powered down the laptop it continued to hum, even on other inputs, until I removed the USB cable.

Should I be looking at the cable to be suspect or the laptop, or god forbid the RR2150

Thanks,

Ranj

I have tried the USB connector, but did not run into the hum issue. I must say that I was not terribly pleased with the sound produced throught the USB, though. I was actually hoping that using the RR2150s DAC vs. the PC's would produce better sound, but it didn't work out that way. Anyway, I gave it up and went back to an analog connection from the PC to the Video ports on the 2150.

I use my RR2150 almost exclusively with the USB input (my G5 iMac is the principle source in the RR2150 system) and have had no problems whatsoever. Worked automatically, without any configuration (Mac sees it as an external sound card).

Unlike the previous poster, I think quite highly of the sound produced by the USB input. To get a handle on it's quality, I used the RR2150 for a short while in my "main rig", where the USB input was compared to my Mark Levinson 390S, both fed from iTunes running on a Powerbook. The RR2150 acquitted itself quite well.

No, it didn't have the bass slam of the Levinson, and was less musical overall, but plenty enjoyable. And, as I said above, I use the USB input every day, although not in a "critical listening" application. It beats the sound from the iMac's own soundcard.

Hey, Guys:

I just today received my 2150, so I have no feedback yet - but I do have a question: Is the "USB Port" for audio input /only/ from my computer, or will it do output as well so I can record stuff with my computer?

Bill

My understanding is that the USB port is an input only.

The USB appears to be for output from the computer only.

I just checked the "Sounds and Audio Devices" in Control Panel. The default UAC3553B USB-DAC (the RR2150 as seen by the PC) offered settings for playback only, whereas the internal sound card offered options for recording as well.

I wonder what format it the USB-DAC decodes, since it is dependent on having a player on the PC to decode the original file, whether it is cd-audio, wav, wma, flac, shn, mp3, etc.

Thanks for the response gonk and cruise. If the port is for playback only (which makes sense, actually), then I have a problem. I have a device that connects to my computer to input and output RCA jacks in the back of the receiver so that the computer can behave just like a cassette player. The problem with the 2150 is then, of course, the fact that it only can accommodate one such recording device. I'll need to either choose between my computer or cassette player, swap the cords when I want to switch, or rig-up some workaround to allow me to switch on the fly.

If I'm completely honest, though, it's very unlikely I'll be recording cassettes any time soon. I'll probably just hook the computer up to the tape input/output jacks and run the output from the cassette into one of the other inputs.

Can't the external processor output double as a second record loop?

I know that most record outputs are not affected by volume level changes on a receiver. Depending on the unit, volume level changes would likely affect either the output to or the return from outboard processing. If the output meant for an external processor is affected by volume level changes on the receiver, then the receiver's volume level would likely need to remain unchanged during any recording session.

From the RR2150 manual, "The external processor loop is a "fixed level" loop. It is not affected by the RR 2150's Master Volume Control." You'd need to enable the External Loop on the front panel and you'd need to have the desired source active (unlike the tape loop, which gets whatever source is selected at the "Record" knob on the front panel), but it should work - assuming you don't need the external processor loop for something else...

I've tested the external loop to use it as a second loop and it works perfectly as a line level input/output. I don't record but I simply wanted to know if worked to send the signal from the RR2150 to another source..... and it indeed does, just remember to activate the external loop button. So, if you don't use an external processor, count it as another aux input/outout. Don't forget the front input jack can be used as an additional input if you really need it. I was initially concerned over the lack of total inputs, but five plus the phono is all I'll ever need.

As gonk did, it really hepls to read the manual if you own a RR2150, or download the PDF version if you're interested in one. I studied mine before I received it so there was no suprises of how it worked. The real pleasant suprise comes from how it sounds:)

Thanks, guys! The external loop suggestion is an excellent idea - I wasn't sure it would work like this based on it's description in the manual, as I'd interpreted it as a signal processing (e.g., equalizing) path. Having to activate the external loop button reminds me of the old "tape monitor" button on cassette decks.

I, too, have been dismayed with the number of inputs on the 2150. This helps.

Does anyone have a suggestion whether the external loop ports would be more appropriate for the computer connection rather than the tape player conncetion? (I don't think it matter, really, as long as I pay attention to the external loop button.)

I wouldn't think that the computer or the tape deck would have any preference between the external loop and the tape loop - the two are doing basically the same thing for recording purposes (a fixed level output). It might depend more than anything else on how you use the two recording devices. If you record to the tape deck a lot while listening to some other source, then the tape deck would be better off connected to the tape loop instead of the processor loop. On the other hand, if you really do think that you're not going to record to tape much anymore, you may want to hook it to the processor loop as a sort of insurance policy ("I don't think I'll need it, but I don't want to have to run extra cables to do it if the need does arise") and let the computer have the tape loop for the more routine recording duties.

I hooked up my RR2150 to my computer using the USB today , and it sounded pretty good actually. Sound quality isn't as good as a CD, but it's not unlistenable either.. I used a .wav format for comparing tracks. I'm still not up to speed on all the varying file formats and sizes when saving music to my hard drive, but I do my best. There was zero background noise, much better than the noisy Creative Live sound card's output.

I listened with headphones mostly, with my Sennheiser 595's being more forgiving than my speakers(Bose 601 series II). The music from the CD's are surely more lively, and it's more noticeable on the speakers than the headphones.

If I can ever get high-speed internet available to our home, I'd use it for some internet radio and other streaming audio for sure. That's ...... if .

-Garth

I'd add only that my experience has been just like fred von lohmann's - perfectly acceptable sound, much better than the built-in computer audio hardware. there was a faint hissing in some recordings over the USB connections, but changing to a better USB cable seems to have banished that. the USB-in was one of the reasons for me to buy the RR2150. I'm still trying to find a good tubed DAC to feed computer audio into a nice system, since I am not about to sink serious money into a universal player when I have several devices in the house that can play anything already. but until then, I am quite happy with using computers as transports.

Very pleased with the USB connection - I have most of my CDs ripped into FLAC and do not see myself ever investing into any kind of expensive CD player - playing music from the PC is a convenience that just can't be beat in my opinion.

Just bought a USB cable the other day and it is so nice not having to dig through 10 different cases looking for the music I want to play. Sound quality is pretty good but having your entire library at you fingertips is priceless. I'm having a blast just searching for songs I have not listened to in years

Oh yeah and one other thing.... For anybody out there with Sirius or XM. You can access the service online and play through your 2150!

The USB thing has me somewhat confused, I went to great lengths to download directly from original CD's, at 320 Kbps on an AAC format, via Itunes. I was under the impression that the UBS would allow the 2150 to process the info, but I can still control volume, bass and treble through windows. Maybe this does not matter, but I am wondering what these levels should be so that I am optimising the capabilities of the 2150. Any thoughts, maybe I should go back to the CD player, but I like the convenience, also a number of people complained about the sound quality when using the USB port, is that perhaps because they are downloading the music with a greater compression, mine seems to sound fine, but I do not have a CD player right now, so it is difficult to compare, as an aside does anyone have Axiom speakers I just ordered some M80's and would appreciate some feed back.

The loss of sound quality that people express is from the compression being used, not the USB connection.

If you want the quality of the original cd, then that's what you should stick with. There is no magic compression technology that sounds as good as the original disc .

I'm a CD listener, I don't download music. AAC is just another form of compression . Apple itunes , to me , is just another way they try to hook a consumer into spending your $$ with them. It seems convenient and all, but convenience here comes at the price of losing musical data, hence quality ..... and CD's already have lost a substantial amount compared to real analogue recordings .

An alternative to using the original CD that strikes a balance between CD (or raw WAV files) and lossy compression like AAC and MP3 would be a lossless compression (such as AAC Lossless or FLAC). That would offer the convenience while sacrificing little or no sound quality.

For what it's worth, I have experimented with iTunes playing through the 2150 using the USB port and using an Apple Airport Express which I connect w/RCA connectors into the 2150 Video ports. My conclusion is that the USB connection is far inferior to the other method.

I tried different PCs using lossless and loss formats and in every case, the USB connection sounded inferior. It doesn't make a lot of sense to me that a wireless connection should sound better than a wired one (using the same source), but I can tell you with certainty that it did in my case and I am perfectly happy with the sonic quality.

That said, I still listen to vinyl and CDs when I have the time to just sit and enjoy, but when I use music as a background for other activities, the Airport Express is a great solution from my perspective.

Thanks for the information, I tried the lossless on I tunes, (by the way I never buy my music on I tunes) it seems to be better. From what I gathered "lossless" is all the same regardless of which provider you choose, the difference is in the speed or ease of use, but the result seems to be the same, the person that suggested he uses RCA cables instead of the USB, I don't quite understand that, does it not mean that the sound card in the PC is making the conversion from digital to analogue, and is the 2150 not better equipped to make that conversion.

My real question is to what extent do the controls in windows’ control panel interfere with the signal to the receiver, I think that since the information sent through a USB connection is digital that those controls can simply be maximized and controlled through the 2150, unfortunately I am just not that technically inclined so my questions may miss the point, I would simply use CD’s or LP’s but I live in a three storey house, and I listen to music on all three floors, so carting CD’s or LP’s up and down is not practical. I just would like to optimize the computer to HI FI connection, I think this lossless may have already done so or it is getting closer in any event.

I just bought the 2150 and I like it very much, still waiting for axiom speakers, arriving today, then I intend to by a second 2150 for the third floor, all computers are on a network so it has the potential to work quite well from an access point of view, if only I can resolve quality. Thanks for listening.

Unless I'm missing something here, a digital file is a digital file. Windows should does interfere with it, since you're only only using windows as a transfer mechanism of the file to your 2150.

Yes a digital file is a digital file, but the volume, bass and treble can be controlled via windows and the 2150. When I disable my sound card the USB stops working. So I am somewhat confused as to where the digital to analogue transfere is actually taking place. I am almost certain it is the micronas chip in the 2150 but why does windows still maintain some control and given that it does should the windows settings be at maximum as you point out a digital file is a digital file so there is only more or less information is my understanding and the conversion to analogue is done by the receiver. So where in your opinion does one set the bass control on windows for example, at maximum or mid range.

I'm sure no expert here, but I can only tell you to do what I'd do myself, and that is do some trials first. I'd start with neutral(or mid if there is no neutral) tone controls, see how that plays with the 2150, and adjust from there. As far as the volume level, max would likely be best.

What media player do you use ? WMP allows you to turn off any audio effects. I'd even try different software players, I'm sure they don't all sound the same.

I empathize with your problem here, I find it kind of ironic that digital music, which was supposed to simplify our musical lives ...... it has done anything but !

Let me try to clear up the confusion.

The RR2150 is a pure analog device (i.e., it does NOT have a DAC). The computer sound card is doing the D to A conversion and passing the info via USB to the RR2150.

No 2ch receiver (that I know of) has a DAC - they are all analog devices. On the other hand, ALL multi-channel receivers sold today have DACs.

Now, the question is what happens when you connect a computer via USB to the 990? Can the 990 accept digital files and do the D to A conversion? Can it upsample the data coming thru the USB input?

(I am guessing YES - Gonk - please correct me if I am wrong!!!!).

I believe this is incorrect. USB is a digital communication interface, and as such it isn't capable of carrying analog audio. The RR2150's USB module contains a DAC as well as the other electronics that allow it to act as a sound card - the PC's sound card is not in the signal path, and the USB module itself serves as a sound card (one might even say that the entire RR2150 becomes a giant sound card when used in this manner). I know that the Model 990 works this way because I've tested it. The RR2150 has to work the same way.

This is typically true. There are of course going to be exceptions, but as a general rule stereo receivers are analog only. Surround receivers must have DAC's to function, since the surround processing is all performed in the digital domain (although I think Fosgate built a purely analog multichannel pre-amplifier a few years ago).

Yes, the 990 can apply processing and do D/A conversion for the USB input. I think the root of Carlos's question, though, is whether Windows mucks around with the audio data prior to handing it off to the 990 or RR2150. On that point, I'm just not sure - I certainly would like to be able to insure that the signal path was as straight as possible within the PC if I were using my USB input for much, but I also have spent enough time with Windows to know that it can hide a few bumps in the road when it comes to stuff like this.

Gonk is correct, USB is a digital interface, it can only transport zeroes and ones, and the RR2150 must have a DAC in its USB port to translate the zeroes and ones into something it can send to the speakers.

That said, the RR2150 (and I would suspect the 990) is dependent on the computer, and the chosen media player to take the file, whether it is WMA, Flac, AAC, MP3 or whatever, and turn it into something that the RR2150 can understand...PCM perhaps?

Otherwise, the manuals would have to list the file formats the DAC could support.

Cruise is exactly right: as with most any PC sound card, the R2150 is going to rely on the media player being used for decoding files like MP3, WMA, FLAC, and AAC (whether that's iTunes or WinAmp or Windows Media Player or...). In the case of these files, it is necessary not only for decoding but also for data management, since I don't know of any way to "play" an undecoded MP3 file to a sound card. The 990's USB input also requires the software to decode Dolby Digital or DTS bitstreams for sources such as DVD's or other video files - it wants a PCM stereo bitstream. I suspect that the RR2150 is the same way.

Ok - makes sense - I stand corrected.

Two questions:

1. On the 990, does input thru USB use the USB DAC or the regular DAC? I am guessing that it uses the seperior regular DACs.

2. When the computer is sending the PCM stream, is it sending at 44.1 Khz or at 48Khz? I remember reading somewhere that, by default, Windows OS send PCM data at 48Khz - some sound cards allow you to transmit at 44.1 Khz. Any info on this?

On the 990, it'd be the 990's DAC because the signal goes through the DSP section (downstream of the USB module) before being converted from digital to analog. As for the computer's PCM bitstream, it can probably do either. Playing a CD straight from the tray would presumably be 44.1kHz unless there was some processing or manipulation taking place, but I'd expect that bitstreams derived from material like MP3's or Dolby Digital sources would be 48kHz. The 990 can handle either, though, so it shouldn't be an issue if sources like that default to 48.

I had a ground loop problem with connecting my computer to my 2150 using the USB port. I had been troubleshooting with Steve at Outlaw on and off for a few weeks. After much trial and error, connecting and reconnecting, I narrowed it down to the audio output of my satellite receiver which I use to listen to Sirius from Dish . A Ground Loop Isolator (Scosche brand)from Wally World solved it .
I know some others have had ground loop problems with their usb , so if you do, the tech guys at Outlaw are more than willing to help.

Now that I've got it solved , and listening to music connected via usb more, I really can't tell any difference between this and my regular CD player playing discs on my computer or using wav(uncompressed) files. While I'm particular about sound quality to a point, I'm no audio perfectionist , (if I was I'd be in an asylum because I'd be chasing what doesn't exist in my world) .... so your results can and will vary.

The bottom line is the USB input is a completely viable option to use. I wasn't sure at first, listening to compressed files, but uncompressed ones and CD's sound as good as they were intended to be.

Wow, and they say Yanks aren't friendly, I really appreciate the input, not that I assume it was all for me.

I think the same way about the USB port. The 2150 has a Micronas chip (UAC 3553B: USB Audio DAC) and as you can see it has DAC in the name, I didn't know what DAC was before reading this page, still don't, but now, thanks to you guys, I understand that it converts digital to analogue, which means windows is not doing the primary conversion, it is taking place in the 2150. Now why does windows retain some control, so far what I have surmised is the that since the computer can only transmit digital information through a USB port, it is transmitting a series of “0” and “1” and therefore there could only be more or less of it, it cannot be qualitative, so I think it is best to put all the volumes on the computer to the max and let the 2150 control the nuance.

I discussed this with the outlaw guys they did not seem to know, Scott suggested I experiment with the levels, I have and this is the conclusion I have come to. However I think that there must be some sound engineer that Outlaw can access that may clarify the relationship between the 2150, the USB and the PC and how to eliminate or keep windows interference to a minimum. It seems I am not the only person that is somewhat confused or at least uncertain about this issue.

I have downloaded my music library in a loss less format and am very satisfied with the results and in case anyone is in the market for affordable, yet incredible speakers check out Axiom M80’s. Outlaw recommended them and Cannucks (that’s Canadians, for those who are not worldly) make them, a little hick town a couple of hours north of Toronto (same policy as outlaw, only sell over the net, check them out for 30 days etc). Imagine with all that goes on in the old US of A, Massachusetts recommends Dwight Ontario, population 89 … 80 make speakers, the rest … beer; just kidding I have no idea really.

- There's an Axiom M3ti floating over my head right now (OK, it's bracketed to the wall, but it's a well-concealed bracket...). It and its sibling on the far wall have been keeping my other Canadian speakers (Paradigm Reference) company for about three years now.

As you've recognized, the USB connection passes a digital signal (using PCM, the signal format used by the trusty CD) to the 2150, at which point the USB interface on the 2150 uses its DAC (Digital to Analog Converter) to produce the analog signal that the rest of the 2150 wants. Even in the digital domain, though, you can still shuffle those 1's and 0's around. Volume control is an obvious one, as is left/right balance, but you could also have equalization (even simple bass/treble adjustments).

Carlos, My best advice is to keep it simple.

Okay, why does windows have some control over the digital files ? It does for the same reason a Cd walkman or portable mp3 player have control over the volume and tone controls . Computers were not intended to be connected to an amplifier any more than a walkman was, therefore the consumer needs a way to adjust the volume and tone. My point here is the "why" of it matters little because it designed function cannot be changed. How you deal with it right now does.

I don't think you need a sound engineer to keep windows influence to minimum, simply keep the EQ off , if you use windows media player. Keep the volume of the computer on max. This is how I listen to my music and it sounds excellent. I use both speakers and headphones.

Enjoy the music

True that, Garth. I believe you're right about simplicity (no EQ, computer volume to the max), but in my case, I'm still finding that music from the USB input is not quite as nuanced as when routed from my CD player. It's a nominal difference, but I can hear it. Of course, the convenience of the USB port is fast making this a non-issue, especially since I've just recently begun experimenting with Internet radio. Didn't know there were so many choices were out there.

Yes, the world of internet radio kind of blows my mind too with all the choices. I also just got into it now that I've got some high speed access. I like pandora.com for one because you have some choice as far as song selection. Between internet radio and Sirius , I have more choices than I'll ever have time for

Tru blu, I'm not sure if you mean the sound from the usb isn't quite as good when comparing a disc played on your pc vs. your cd player , or you are referring to streaming and or compressed audio (which doesn't sound as good as a real cd, despite the label "cd quality").

Hey Garth. I'm actually noticing a small difference between discs played in my Mac (through iTunes) and those played on my CD player. There's more clarity and nuance using the disc player, and I have to crank RR 2150 volume louder using the USB input. My wife noticed also. Maybe there's a simple solution I'm not aware of, but I'm not all that bothered by it.

That's great Garth, thank you, I use Itunes, lossless format, it sounds great, I just found the equalizer, and turned it off. I like music, I don't claim to understand technology beyond the basics. I tried to find another equalizer in windows, could not, is that the suggestion, turn it off in Itunes, volume to the max and don't worry about windows. I access the music on two different computers, the sound card is called soundmax on both, but I think they must be different versions, because one has a base & treble control the other doesn't. I am less concerned now that I have been listening to the music for a while, I just got the system and am still fiddling, I'll get there.

Carlos, Glad to hear you figured out Itunes. On Windows media player, the EQ is listed under View-Enhancements, then choose "Show enhancements" . Now you'll see the enhancements on the bottom of the screen, and to choose between them use the < > arrows in blue. There are 8 choices. Go through each one just to check the EQ, SRS WOW effects, and "Crossfading and Auto Leveling" are off. Also make sure the play speed is set to normal, it's probably set that way by default, but you never know.

BTW, as Gonk stated earlier, using the USB connection, the 2150 becomes your sound card. Try connecting some headphones to your sound card or computer while you have the 2150 connected, and you'll find there is no output. You can only have one sound card active at a time. Disconnect the 2150 and it goes back to your sound card. That's the beauty of using the 2150, no matter quality of your sound card on your computer, connect the 2150 and you have high end sound. I get some RF interference from my Sound Blaster card, so using the 2150 instead is very welcome.

Done Garth, thanks again, the equalizer was on in Windows, it is now configured as you suggested.

Garth "sounds and audio devices properties" in the control panel maintains control over volume and if you hit the advanced twice it takes you to a bass and treble screen with low and high settings, these still affect the 2150, I have set volume on max and the treble and bass in the middle and it seems to be fine, I am assuming at this point these are simply controls that do the same thing as the controls on the 2150.

Is there a problem with connecting the RR2150 to the computer through a USB hub? It seems that more often than not, I have to pull out and push in the usb cable to "wake up" Windows into seeing the UAC 3553B USB DAC as a "mixer device" in the speaker properties under "volume."

I sometimes use an Airport Express too. I have not tried the RR2150's USB connection.
Interesting that you find the AE betters the direct USB connection. Must speak to the DAC in the Airport Express. Too bad we can't make use of the AE's optical digital out with he RR2150 - everyone seems to agree that the AE's digital out really shines.
FWIW, I find I get my best 'CD Quality' sound using FLAC files. I use Play via Airfoil to the Airport Express.