Sound cues from a laptop

[Zulu]

Hi, folks.

I am normally a lighting technician, but I'm having a go at improving our (Church Hall Theatre) sound quality. I believe I have the necessary gear, but maybe need a few tips:

We have:

• A big pair of EON 15P powered speakers.
• A Behringer mixing desk (4 mono channels, + 4 stereo channels, and lots of knobs)
• A Laptop with an unknown internal soundcard. Output via the headset socket.

 

We recently obtained the powered speakers, and I was expecting fantastic volume and quality. However, it's not happening ! Just can't get the VOLUME !

 

My playlist is a mixture of music and sound FX, sourced from all over the place, (probably at different volumes!), and cued up using the Multiplay software.

 

I know little of 0db, bit rates, etc.

 

I suspect I should:

• Even out volume levels of source music (how?)
• Set up my laptop ? (How?)
• Fiddle with the gain knobs on the speakers (currently set at max)
• Know what the knobs/faders on my mixing desk are supposed to do.

Can anyone offer some basic tips / rules etc ?

 

(ps, I tried putting a small pre-amp between the laptop and the desk. This gave loads of volume but terrible distortion, and, when volume reduced, a muffly sound quality)

 

thanks for any pointers . . .Zulu.

[paulears]

Something is adrift. Laptops, especially Dells are well known for nasty hums and buzzes, but laptop audio quality is usually pretty reasonable - frequently better than some elderly internal sound cards in older PCs.

 

First test is what does the laptop sound like on decent headphones?

If ok, then plug into the mixer. Into either two mono channels or a stereo input. What does this sound like on the same headphones. Should be the same or very very close. If you are using the stereo input, and it's quiet, then try two of the mono channels and see if you can get a little more gain. Most importantly, I assume that plugging a mic into the mixer means plenty of volume from the eons?

 

If some of these steps don't seem to work - suspect cables. I presume you have a stereo 3.5mm jack going to two phonos or two jacks for the mixer.

 

Can you explain a little more what is happening?

[Mat]

If you're looking to easily play sound from your laptop, a freeware that I would highly recommend is Multiplay. A quick google will get you the download website. A nice little free bit of software which let's you play Audio, Midi and most likely more. I haven't really had a proper play with it but for what I use it for, it does the job.

[GridGirl]

If you're looking to easily play sound from your laptop, a freeware that I would highly recommend is Multiplay. A quick google will get you the download website. A nice little free bit of software which let's you play Audio, Midi and most likely more. I haven't really had a proper play with it but for what I use it for, it does the job.

 

Did you read the OP's post?!

 

and cued up using the Multiplay software.

[Bobbsy]

A few random thoughts...

 

First, you need to read up on the large subject of "gain structure" (sometimes called "gain staging"). You have lots of places in your system tha will affect the volume at the far end: the orginal material, the software volume control on your laptop, possibly a hardware volume control on your laptop, the trim pot on the input to your mixer, the channel knob or fader on your mixer, the master level control on your mixer and finally the input level control on the amp in your speakers. Your goal is to set each of these at an appropriate level to hand the sound onto the next stage without it being too low at one point then cranked way up at the next.

 

Second, and related to the foregoing, spend some time on your source material. I always have some form of DAW software installed on the same computer I use for playback and spend as much time as it takes to normalise, compress, sometimes EQ, etc. etc. the music and FX you'll be using. I should say that there are two basic schools of thought on this. Some (like me) like to have everything at a matching level on the computer then use either Multiplay or the Mixer to set an appropriate level. Others set levels of the files so the playback can be preset and left. There are advantages and disadvantages to both methods but you need to think about which works best for you.

 

Third, if you can spend any money at all, get away from the headphone output and acquire an external USB audio interface. Laptop built in sound cards are universally rubbish and a fragile 1/8th inch connector is a worrying potential source of failure. Also, having a software level control in the way is asking for something to be at the wrong level.

 

Fourth, yeah, knowing what all those knobs do is what is known technically as a "good thing". :)

[Zulu]

Thanks, Guys. some great tips and pointers here.

I'll definatley be doing the tests suggested by Paulears. (Paulears, yes, I do have loads of volume on the Microphone, plugged into a mono channel, and the gain turned up sufficiently.).

 

I've noticed the mono channels have an input gain control, whereas the stereo channels don't. (Is that usual?). So I'll be trying using those channels. Sounds highly promising.

 

Bobbsy, I think I agree with you: "Normalise everything at a standard level, and do local adjustments in Multiplay." (I only found out what "Normalise" means today. !!). Some of your other comments look good: a bit of learning, and maybe a bit more hardware. (Is a "external USB audio interface" what I might call a sound card?)

 

How / where do I normailse ? DAW ? (never heard of it). Audacity ? Anything else? (Church Hall, cheap as chips, of course !!)

 

shan't be touching our system until next week, as we are now mid-run, and have just about got things at an "OK" level. I'll report back.

 

many thanks, Zulu.

[GaryM]

Just another pointer. Without details of your mixer input connections it's hard to advise, and hoping I'm not being too patronising, but make sure that you are connecting your laptop to the Line inputs of the mixer and not the Inserts (or the Mic inputs of Mono channels). If the channels have a Mic/Line switch make sure that these are also set to Line.

[ramdram]

As a general topic for discussion and not directed at the OP and the premise it's not "continuing the patronising" theme...suggest you read and reread the manuals, then go through the manual with "hands on" the desk.

 

If you have time you might even find some tutorials on YT...amazing what gets posted.

 

It may be of course that "a" desk could be duff or, my favourite target, duff cables and leads/connectors. Some cables can get abused for ages and they are never the first point in system fault finding...and you don't need a manual to test "a" cable.

[alistermorton]

thanks for any pointers . . .Zulu.

 

Is the output from the laptop matched to the input of the mixer? I've always found that just plugign the hones output of a sound card into the line inoput on the amp results in a horrible thin and lifeless sound. The sound card will likely be meant to drive low inpedance headphones, the line input impedance will be somewhat higher. A load resistor on each output channel may help?

[timsabre]

Is the output from the laptop matched to the input of the mixer? I've always found that just plugign the hones output of a sound card into the line inoput on the amp results in a horrible thin and lifeless sound. The sound card will likely be meant to drive low inpedance headphones, the line input impedance will be somewhat higher. A load resistor on each output channel may help?

A thin and lifeless sound is not due to this... low drive impedance into high input impedance is no problem. It's trying to run something with a high drive impedance into a low input impedance that gives you thin sound.

[ojc123]

On the basis of recommendations from the Blue Room I got one of these. It cured all my problems. Well all the ones related to laptops and PA systems anyway.

 

It just goes into the USB port of the laptop and plugs into two XLR sockets. The Jack version is also available and might be better if there is any possibility that phantom power might be applied. Apparently they don't like phantom power. On some laptops I've needed a restart before it works properly.

 

If you need to learn about gain structure

is a good start. Mr Rat is quite good at his job.

[ninjadingle]

Zulu - one thought just occurred. What operating system are you using on your laptop?

 

Multiplay has known issues running on Windows 7 with MP3 giving a crappy sound - see here.

 

Try running your music / SFX through Media Player and see how that sounds?

[Zulu]

Zulu - one thought just occurred. What operating system are you using on your laptop?

 

Multiplay has known issues running on Windows 7 with MP3 giving a crappy sound - see here.

 

Try running your music / SFX through Media Player and see how that sounds?

 

I'm using Windows XP, so the Windows 7 issue shouldn't be aproblem.

 

thanks anyway, Ninjadingle.

[Zulu]

Reporting Back . . .

I thought I'd add an epilog to this saga: GOOD NEWS ! I tried a couple of the things suggested, and I glad and grategul to say I found the missing volume.

 

A combination of:

Using 2 mono channels

learning a bit of gain structure

Adjusting / Normalising the source files

 

So many thanks to all who contributed. RESULT !!

[Bobbsy]

Thanks for coming back...it's always nice to hear that advice hasn't gone into a vacuum!