ANYONE have issues w/ MBox and PowerMac Dual G5 ?

[moebius_loop]

Anyone else having noise issues recording with MBox on an PowerMac Dual G5 ?

I have a hissing noise being audible through my MBox, running ProTools 6.4 and recording at highest gain settings (when gain knobs are anywhere between three quarters and full). I have recorded synthesizers, effects and vocals using my MBox, and the noise is an issue when doing quiet vocal recordings (spoken word or a capella singing).

I recorded the noise with the gain controls set all the way up and the input/playback knob set all the way to input. I was hoping that the noise which I was seeing on the ProTools level meters, and hearing through my headphones from the MBox headphones jacks, would not actually be recorded. I had no mics or any sound source whatsoever connected to MBox's inputs. The noise DID show up in the recording.

I had my PowerMac G5 Dual 2.0 GHz checked out by a local Apple Authorized Service Provider and they said that the unit was working normally. The tech there knew about USB audio recording, and told me that the noise showing up when the gain knobs were turned up that high (between 3/4 to full gain) was common.

I don't know if this hissing issue is the same audio bleeding issue in the following post from the Answerbase - http://answerbase.digidesign.com/detail.cfm?DID=27714

In his post for a similar issue ( http://duc.digidesign.com/showflat.p...fpart=1#714816 ), Lang Elliott mentioned that the CHUD toolkit for the G5 might help with this, but has not posted any results.

Your thoughts ?

[tele_player]

Just try a powered USB hub, to see if it makes a difference. The Mbox is susceptible to electrical noise on the USB power.

[moebius_loop]

Hi tele_player,

Are you saying that the electrical noise will be dissipated, grounded or routed differently with a powered USB hub ?

Regardless, this works out because I needed to buy a USB hub anyway, for all my other USB peripherals, so if it also took care of the hissing issue I would be in HEAVEN ! Can you recommend a good brand ?

Thanks in advance

[tele_player]

First, I was saying to just TRY it, no guarantees. The idea is that it would block the noisy power from the G5, and drive the Mbox with the less noisy power from the wall wart. Over the past couple years, this has been a solution for some users complaining of Mbox noise, though I don't recall that any G5 users tried it.

Sorry, I don't have a recommendation. But I'd buy from a place with a liberal return policy.

[moebius_loop]

Hi tele_player,

I understand that your suggestion may or may not work but, like I said, I was looking to buy a USB hub anyway for my other USB peripherals (printer, external cd burner, etc), so I will not be returning it regardless of whether or not it resolves the MBox noise issue.

Thanks for your quick responses

I will definitely post the results once I have purchased the USB hub and tried it with the MBox.

[moebius_loop]

I guess I can file this reply under "better late than never":

I have been doing a lot of mixing and remixing, and not any recording via my MBox1 since I first reported my noise issue with the 2.0 dual processor G5 in this thread. Well, I have recently had occasion to get my hands on a powered USB hub and it DID work with my MBox1 and it DID reduce the amount of noise generated by the preamps when the gain is turned up to between 3/4 of the way to all the way. There is still a little bit of noise when the gain controls are almost all the way up, but the noise is significantly reduced.

I wonder if this may also have to do with the fact that the powered USB hub allows me to place my MBox1 a lot further away from my computer screens (which are crt), thus reducing any interference those may be causing ?

Now that around a year and a half have passed, I figured I should let anyone who still may be experiencing the problem know the results in my specific case. BTW: The noise was really only significant for me when recording using microphones. Instrument and Line input settings always seem(ed) to work fine.