Help needed urgently

Duke Leonal Felmet

Hello,

I am setting up for sound in a small theatre and I am getting hissing sounds from the speakers. The usual setup for this theatre is to input CD/minidisk players into a 12-channel sound desk (fairly basic). However, we wanted something a bit more advanced so I am running a midi controller into Reason 4, which is outputted to a USB audio interface and then into the desk via red/white cable.

However, when I attempt this there is a hissing noise from the speakers. I tried using two guitar cables instead of the red/white cables, but the hiss remained. I tried bypassing the audio interface by running a headphone jack/red & white cables from the laptop into the desk, but the hiss remains. Adjusting the gain on the desk has no effect. I also tried playing mp3 files and the hiss remains, hence it is not Reason. I tried a different laptop, the hiss remains.

The only way I can get rid of the hiss is to use a CD or minidisk, or an mp3 player using the same headphone to red/white cable above.

I am stumped. I have two days to find a solution. Any ideas?

GTE

Initially I thought the laptop was giving off the usual interference they do but the gain should make that worse.

Does the hiss go away when you switch the laptop/audio interface off or if you keep them on and completely disconnect them from the desk?

It sounds like a problem being induced by the laptop/laptops.
Ground loop somewhere? Take the laptop off external power and run it through the audio interface.
Get balanced connections if possible and use them in any case.

If the hiss goes away when you disconnect the laptops power try plugging the laptop into the furthest most away power socket you can find.
If this is indeed the case you need to find a power outlet that is separate to the ones used for the desk.

EDIT: DamagedTrax idea of a DI with a ground lift is a gudun!
I have been very lucky with ground loops in my mish mash "studios" and live recording setups so I have never had to try much to solve it!
Time to take some notes!

DamagedTrax

^^ what he said.

if you cant use the laptop on battery power then run it thru a DI with a ground lift.

Duke Leonal Felmet

Ok, plugging out the laptop worked!

How do I run it through a DI with a ground lift? I don't know what that means.

Thanks so far!

DamagedTrax

if plugging out the laptop worked you dont need a DI as it was a grounding issue with the power supply.

to use a DI box from laptop soundcard you'd need:

3.5mm jack -> dual mono 1/4" jack cable.
2 DI boxes to run in stereo.

DI boxes have a little button on them saying "ground lift" or "grd" just flip it on.

Duke Leonal Felmet

Thanks guys.

madtheory

PS this sound is normally called "buzzing" not hissing.

Jagle

for someone setting up the system you seem to have the most basic knowledge, just an observation

DamagedTrax

Jagle wrote: »

for someone setting up the system you seem to have the most basic knowledge, just an observation

thats some helpful posting dude :rolleyes:

Jagle

DamagedTrax wrote: »

thats some helpful posting dude :rolleyes:

come on, im setting up the sound in a theater and i dont know what a DI is, a 1/4" jack cable for RCA/ Phono

god help them if anything does go wrong

DamagedTrax

so? other than the info we've been given, god only knows what the situation is..

anyway, why would you even care? dude asked a question and got his answer. im failing to see the drama in it

Jagle

its just funny a guy with no clue of the basics is doing something much harder, if you dont know how to change a tyre would you agree to give someones car a service

DamagedTrax

:P

Jagle

why is it ok to have no clue about the basics and put yourself forward for a job to do the sound in a theater.
thats the point im making

DamagedTrax

who cares? seriously..

its his gig. not yours.

GTE

Jagle wrote: »

why is it ok to have no clue about the basics and put yourself forward for a job to do the sound in a theater.
thats the point im making

Why is it OK for you to post without correct punctuation/grammar?
If you have no clue of the basics then why put yourself forward to a text based forum?

If you see where I am coming from my point is you don't need to know some of the basics to do a decent job, in your case getting your point across without constructing a sentence properly.
It is not a biggie if you don't know what to call an RCA plug. So what if it is basic stuff. Maybe there is a good reason for this, student production, helping out a friend in an arts course etc.

The OP already seems to have his head screwed on if they can identify that Reason with a midi controller can be a much more flexible solution for sound work in a theater. Also using a USB interface first and only using the headphone jack as a last resort/to test means something too. So I would cut him some slack and just drop it as all that is going on here is you getting riled up over something in which you do not know the full story on.

They also seem to know about connectivity between the computer and the desk as they have the interface so perhaps as it was such an urgent call for help, trying to remember what the real name of something is, getting it wrong and having the thread derail is worse then giving the most obvious name you can think of and if I do say so myself having the problem diagnosed in the first reply.

EGO BOOST!!!

After that the thread can go to hell, a bit like this.
Now, lets all have a cup of tea and ask the OP to report back on how the show went.

Jagle

possibly because i suffer from dyslexia, possibly because it doesnt matter.

you know what does matter, wanting to get into sound, or audio based work, without an idea of what the tools are called. how can you properly work with them and communicate to other people.

and my point is just if you dont know what a DI is what are you going to do if something goes wrong like

GTE

Jagle wrote: »

possibly because i suffer from dyslexia, possibly because it doesnt matter.

you know what does matter, wanting to get into sound, or audio based work, without an idea of what the tools are called. how can you properly work with them and communicate to other people.

and my point is just if you dont know what a DI is what are you going to do if something goes wrong like

Oh calm down dear. We all start learning from somewhere. This doesn't sound like the O2 or the Grand Canal Theater so just drop it. We have no right to probe into the OP's life or make pass-remarkable assumptions like you are making.

We can do one of at least three things on Boards:
1) Helpfully answer questions as they are asked
2) Ignore the thread
3) Post while refusing to even attempt to help and just bicker, moan and complain about the OP and reason the thread was made.

In different situations on this forum each can work but in Music Production I feel is no place for the third thing.

Additionally we do not know any information about him to even base a fair and logical criticism in the first place, which is the OP's choice. If the OP sought it and provided the right information I am sure only helpful, positive and constructive posts would be made from the majority of the Music Production crew here who, indecently would choose option 1.
It is what I have always experienced.

I have taken note of your point and where you lay with regards to what I have just said and that is that from me. Tea time.

I would personally like to hear how the gig went for the OP but of course, I don't expect it.

madtheory

You have no idea of the situation. For all you know it could by volunteer based amateur dramatics, or a mini company for a TY project. Don't make assumptions...

Neurojazz

Keep it civil please - comment on the post, not the poster (that's boards.ie rules) - makes the place a lot more amicable

Duke Leonal Felmet

The show went perfectly, despite me not knowing the technical jargon for cables.

Shock.

Horror.



Thanks to those who helped.

Duke Leonal Felmet

Having re-read some of the posts I thought I would elaborate. I was providing sound equipment for an amateur drama production which needed something more flexible than a CD. I have been playing live music for fifteen years and have taught myself to use Reason and Ableton for home recording, thus I had the I/O interface and midi controller, and I knew sounds could be loaded into the NN-XT so I thought this was a good solution. Of course, I have no formal training in the subject, but I am certainly not a beginner either, I just don't know the names of some cables and never heard of a DI. In my fifteen years of live performance I never once required one, but according to some not knowing these crucial facts renders me a complete novice. People are entitled to their opinion, I guess.

As for this forum, I have been reading here now and again because of my interests, and I knew it would deliver the goods, and fast! I will no doubt return again for advice, I just hope certain members don't jump to conclusions so quick next time.