CMS Author Craig Vecchione Posted December 12, 2012 CMS Author Share Posted December 12, 2012 Originally Posted by StratGuy22 Plug it into a UPS. The UPS is plugged into the power, not the laptop. The laptop is running off the UPS battery. Note that this is true only for online/double-conversion type UPS's. These are typically more expensive than offline and line-interactive designs. Link to comment Share on other sites More sharing options...
Members abzurd Posted December 12, 2012 Members Share Posted December 12, 2012 Originally Posted by dboomer There IS a solution for that! There IS? or there WILL BE? Link to comment Share on other sites More sharing options...
Members StratGuy22 Posted December 12, 2012 Members Share Posted December 12, 2012 Originally Posted by Craigv Note that this is true only for online/double-conversion type UPS's. These are typically more expensive than offline and line-interactive designs. True. Buy the more expensive one, then you are setup for any future gigs as well. Link to comment Share on other sites More sharing options...
Members Miko Man Posted December 12, 2012 Members Share Posted December 12, 2012 Originally Posted by StratGuy22 Plug it into a UPS. The UPS is plugged into the power, not the laptop. The laptop is running off the UPS battery. But if the laptop's power supply is too noisy, even a double-conversion UPS won't help. Mark C. Link to comment Share on other sites More sharing options...
Members RoadRanger Posted December 12, 2012 Members Share Posted December 12, 2012 Originally Posted by dboomer There IS a solution for that! Do tell ? Link to comment Share on other sites More sharing options...
Members RoadRanger Posted December 12, 2012 Members Share Posted December 12, 2012 You can get a 12V adapter for your laptop and just bring a couple 100 lb deep discharge batteries with you . Link to comment Share on other sites More sharing options...
Members dboomer Posted December 12, 2012 Members Share Posted December 12, 2012 Originally Posted by RoadRanger Do tell ? Point to point with wireless is easy. Don't use analog wireless! It has limited frequency response (by FCC rules) and little dynamic range so you're gonna get the quality of a cassette with Dolby noise reduction. In fact the compander circuits are very much like that. The other thing with frequency response on analogs is it changes with level OTOH ... our digital units (even the cheapest one) has flat 10 Hz to 20 kHz frequency response and a full 115 dBa dynamic range with no gimmicks. Most analog doesn't have much low end below 50 Hz and they don't pass transients very well at all. Link to comment Share on other sites More sharing options...
Members agedhorse Posted December 12, 2012 Members Share Posted December 12, 2012 I like this solution. In fact. A quality iem system might be the least of the evils. With good units, the performance is not as bad as don suggested, though this is an application where digital wireless really does shine. Originally Posted by flanc The only way I can see to do strictly under his conditions is to use extended life or multiple laptop batteries...and yes, this is ridiculous rule. Would he take an output from an "old school" cd based system? I'm not recommending this, but an "outside the box" idea would be to connect your laptop wirelessly to his mixer through an IEM system or something similar. Take the headphone out of the IEM receiver into a stereo pair on his mixer and output your line level audio into the sender unit. Now, admittedly, this introduces more issues than the laptop power supply...but if the guy is just being hard headed...it might be an ugly work around. In that line of thought...I'm guessing there is not optical out (Toslink) on your system and an input on his...a fiber connection wouldn't cause any AC problems. Link to comment Share on other sites More sharing options...
Members dboomer Posted December 12, 2012 Members Share Posted December 12, 2012 Originally Posted by agedhorse With good units, the performance is not as bad as don suggested, The analog units I measured here are from manufacturers that start with "S" and cost just a bit less than $1000 each. The digital example is a XD-V30. If you're alright with this then I am . [ATTACH]350535[/ATTACH] Link to comment Share on other sites More sharing options...
Members spottyaudio Posted December 12, 2012 Author Members Share Posted December 12, 2012 i am going to try and push the di solution first because i know i would be the one buying the digital wireless unit, and i'd need two because the person who made up the dj schedule set it up so that each dj only has 45 minutes, so we'll be switching them out rather a lot. it was not a smart move on my part to decide to be helpful, but i was going to be there anyways whooping it up for the weekend and the person in charge of the musical events and shows was struggling badly, and i felt bad for him as a young kid new to getting ****ed on by people who think they are gods gift to fan convensions..so i offered help.my role is manage the djs, keep them on schedule, and work with av to get what we need provided. some of the djs, myself included, use cdjs and a mixer, but most of the "tallent" used loosely, is laptop based and has never even touched a real turntable, let alone a cdj.i'll get through it, and whomever said "if half the tallent walks away, maybe they will learn something?" god i wish you were right.. Link to comment Share on other sites More sharing options...
Members RoadRanger Posted December 12, 2012 Members Share Posted December 12, 2012 I've been using one of these:http://www.zzounds.com/item--ARTDTIand a common 1/8" trs to dual RCA cable or one of these:http://www.musiciansfriend.com/acces...33053000000095 Link to comment Share on other sites More sharing options...
Members agedhorse Posted December 12, 2012 Members Share Posted December 12, 2012 Originally Posted by dboomer The analog units I measured here are from manufacturers that start with "S" and cost just a bit less than $1000 each. The digital example is a XD-V30. If you're alright with this then I am . [ATTACH]350535[/ATTACH] I am more familiar with the brand that begins with A, but the curve is similar, and with very small amounts of corrective eq (at a penalty of a couple dB of increased noise), you can get well within the acceptable specs given the (typical) playback transducer's response... especially considered the DJ genre's acceptability. The companding has gotten much better in practice with IEMs, and while it may be a problem under some conditions, I think it would be acceptable under most. I agree that this is one area where digital wireless has a pretty clear advantage (broadband program), but better may not translate to better for many users. Link to comment Share on other sites More sharing options...
Members StratGuy22 Posted December 12, 2012 Members Share Posted December 12, 2012 Personally I wouldn't deal with such people. Life is just so much easier without something like that. There's always a know-it-all or two at these things. Better just to pay your $5, sit in the crowd and enjoy the {censored}show. Link to comment Share on other sites More sharing options...
Members Keyrick Posted December 12, 2012 Members Share Posted December 12, 2012 USB to audio interface. It takes whatever grounding scheme that the laptop uses, if it even has a grounded power supply, out of the loop. You will have to change the output device preference on your laptop to USB, but I have found this to work with Apple laptops rather well. Link to comment Share on other sites More sharing options...
Members RoadRanger Posted December 12, 2012 Members Share Posted December 12, 2012 ^ Don't think I've ever seen a USB audio out that was isolated from the laptop's ground Link to comment Share on other sites More sharing options...
Members Keyrick Posted December 12, 2012 Members Share Posted December 12, 2012 Originally Posted by RoadRanger ^ Don't think I've ever seen a USB audio out that was isolated from the laptop's ground Well, you may want to look. Not all "Line Lump" power supplies have a grounded input. When there is no EGC on the input to the laptop power supply, the "Ground" that is applied to the sleeve of the line out on the laptop must be derived somehow. I don't believe there is a standard method to achieve this derived ground. While it is true that the USB cable has a shield conductor, not all interfaces will pass that connection to the audio outputs. It may be that the outputs of the DACs in the interface have no connection to the USB input at all. This method may provide a better frequency response than the audio circuitry on the laptop. It is also likely that this solution is less expensive than a wireless scheme. I am not saying that the other methods mentioned won't work. I am saying that the USB scheme has worked for me, on three different hardware platforms. I would respectfully suggest that you try this method before you condemn it. Link to comment Share on other sites More sharing options...
Members spottyaudio Posted December 12, 2012 Author Members Share Posted December 12, 2012 that art unit looks a lot like the unit i had a friend make me awhile back though mine does not have xlr inputs, but does have a 1/8 stereo inputs. i'll pick up one of those if only to have on hand. i'm not going to spend money to make there show work just because someone is being stubborn, so while i'd love to just do the wireless thing, its not within the scope of budget or will for this shows success. Link to comment Share on other sites More sharing options...
Members RoadRanger Posted December 12, 2012 Members Share Posted December 12, 2012 Originally Posted by Keyrick I would respectfully suggest that you try this method before you condemn it. Any particular USB I/F you've had good luck with? As I said I've not seen one that doesn't have its output grounded through the USB port. Kinda hard to "try" if one doesn't know what particular one to try, no? Link to comment Share on other sites More sharing options...
Members nchangin Posted December 12, 2012 Members Share Posted December 12, 2012 Originally Posted by Keyrick USB to audio interface. It takes whatever grounding scheme that the laptop uses, if it even has a grounded power supply, out of the loop. You will have to change the output device preference on your laptop to USB, but I have found this to work with Apple laptops rather well. Same experience, once used a USB interface buzz went bye bye. This was with a PC however not a Mac. Link to comment Share on other sites More sharing options...
Members Keyrick Posted December 12, 2012 Members Share Posted December 12, 2012 Originally Posted by RoadRanger Any particular USB I/F you've had good luck with? As I said I've not seen one that doesn't have its output grounded through the USB port. Kinda hard to "try" if one doesn't know what particular one to try, no? I have used the M-Audio and the PreSonus units. Have a look at the link. http://www.musiciansfriend.com/audio...catId=site1YBK Link to comment Share on other sites More sharing options...
Members RoadRanger Posted December 12, 2012 Members Share Posted December 12, 2012 Originally Posted by Keyrick I have used the M-Audio and the PreSonus units. Have a look at the link. Are you specifically talking about those units with a separate power supply as opposed to the typical "DJ" type units that are USB port powered like this one? http://www.musiciansfriend.com/pro-a...l-dj-interface Link to comment Share on other sites More sharing options...
Members Keyrick Posted December 12, 2012 Members Share Posted December 12, 2012 Originally Posted by RoadRanger Are you specifically talking about those units with a separate power supply as opposed to the typical "DJ" type units that are USB port powered like this one? http://www.musiciansfriend.com/pro-a...l-dj-interface No, that is a Numark unit. I am talking about devices like these: http://www.musiciansfriend.com/pro-a...cording-system http://www.musiciansfriend.com/pro-a...obilepre-mk-ii And the PreSonus unit has TRS balanced outputs. Link to comment Share on other sites More sharing options...
Members agedhorse Posted December 12, 2012 Members Share Posted December 12, 2012 For those of us who have to deal with USB, there can indeed be a problem with ground loops. I saw this myself when somebody came in with a USB connected analyzer app. and there was a 60Hz bump in the response of my system that I KNOW for a fact is not there. It was >6dB too, he isisted that my system was responsible and that it was my job to correct it. I pulled out my (real) analyzer and the bump was not there. The cause ended up being a ground loop on his measurement system. Here's an application note for you industrial guys: http://www.analog.com/static/importe...ound_Loops.pdfAlso, the USB may not be connected to ground proper, but to circuit power supply common that may then be referenced to ground (via a bias supply). This stuff can get very tricky, and what works perfectly in one application may cause a problem with another and vis versa. Link to comment Share on other sites More sharing options...
Members fdew Posted December 12, 2012 Members Share Posted December 12, 2012 Originally Posted by agedhorse Also, the USB may not be connected to ground proper, but to circuit power supply common that may then be referenced to ground (via a bias supply). This stuff can get very tricky, and what works perfectly in one application may cause a problem with another and vis versa. Sounds like the USB version of the "Pin 1 problem" Link to comment Share on other sites More sharing options...
Members agedhorse Posted December 12, 2012 Members Share Posted December 12, 2012 Originally Posted by fdew Sounds like the USB version of the "Pin 1 problem" Kind of the same thing. The problem is that USB was never intended to do the things that it is being asked to do. So it's like fixing problems that were never anticipated to be a problem when the protocol was developed. Link to comment Share on other sites More sharing options...
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