My Mackie HD1531 has a high pitched whistling sound, all other speakers work fine with the same power connection and desk connection. It whistles regardless of whether it has a sound input or not.

If your Mackie SR1530 is powering on but you're not getting any sound, there could be a number of potential causes. Here are a few things you can try to troubleshoot the issue:

1. Check your connections: Make sure that all cables are properly connected and securely plugged in. Check both the cables going into the speaker and the cables that are connected to your audio source.
2. Check your audio source: Make sure that your audio source is turned on and properly connected. Try connecting a different audio source to the speaker to rule out issues with the source.
3. Check the volume levels: Make sure that the volume on both your audio source and the speaker are turned up. Try turning up the volume to see if you can hear anything.
4. Check the input settings: Make sure that the input settings on the speaker are correct. For example, if you are using an XLR cable, make sure that the input on the speaker is set to XLR.
5. Test the speaker with a different audio source: If you have access to another audio source, try connecting it to the speaker to see if you can get any sound.

If none of these troubleshooting steps work, there may be an issue with the speaker itself. It may be a good idea to contact Mackie customer support or a qualified audio technician for further assistance.

You need to contact Mackie support for their recommendations. Here's the links-
Warranty Repairs Parts Mackie
Contact Support Mackie

Some kind of feedback perhaps? Are you using a multi core with sends & receive inside it but NOT individually screened? i.e. "pick up" inside the cable? Is it both speakers? Try them one at a time in case one is faulty but affecting the other? Unplug the input leads & see if the speakers by themselves are making any sound ( a small hiss?) If the speakers with no input (but powered :-) makes no whistle then it's coming from other gear...... Also the speakers may have switch mode power supplies & if you don't have a decent ground you could have problems. Make sure you have a good ground connection back to the fuse board. If you studio is in a shack at the end of the garden running on extension cords you may need a local connection to ground..... Good Luck!

Sound like either the crossover or the driver has blown or, if you're lucky there is a loose connection internally if you have only checked external connections.

Make sure you are using BALANCED interconnection cables to the speakers, either XLR or TRS connections. ALSO make sure all interconnected equipment such as the speakers AND the mixer are powered from the SAME receptacle at the venue... yes you have to run extension cords... the pro's do it so they don't have hum and other noise and don't damage their equipment.

Consider having it reconed... usually costs half of new speaker. Search google for "speaker repair" such as
http://www.reconingspeakers.com/speaker-repair/repair-services/?gclid=CNjQmrqT96kCFRJ6gwodVlDddw

Make sure you have ALL interconnected parts of the system powered from the SAME receptacle or power conditioning module. This MAY require you running an extension cord back from where your speakers plug in to supply power to the mixer. The ground bounce in power wiring in building can cause feedback or even destroying the sensitive input circuits of your system. As an electrical engineer I see these problems frequently. I think they should include this information with sound equipment user manuals, but they don't and people have trouble and damage their equipment. Doing this MAY also fix the problem you are having.

Did you have this speaker AND the device that drives it connected to the same power source? If run by a mixer you MUST run a power extension from the same place your powered speakers are powered to the mixer. Ground bounce due to wiring in a building can destroy input circuits due to ground faults and static discharges. ALWAYS use balanced lines either XLR or TRS cables to interconnect the audio.

Also verify your power receptacle is properly wired. Carry one of those plugs with the indicators showing receptacle is wired correctly. Don't plug anything in until you verify it. Some venues are noted as having bad electical service.

Let your speaker sit for a minute and repower it... sometimes they have a lockout that takes time to reset.

You can try this site:

http://elektrotanya.com/mackie_sr1530_active_speaker.rar/download.html

This MAY be very close to your system... there are several parts to the schematic in this compressed file...

OFTEN companies do NOT re-engineer things so one has to use intution as to what the model number thisng might be listed...

You often find modules are identical between units even though the model is labelled differentely.

First thing is to run a known signal from a simple device like a small CD player to verify the problem.

If these are driven from a mixer, the EQ could be set to kill the highs.

Assuming it isn, something simple like an EQ setting, probably the units will have to be serviced. I know you would already have checked the EQ on the back of these things as a first step.

Remember to ALWAYS power these from the same source as the devices connected to them to avoid ground loops and damage.

Supersonic feedback can fry these. Oscillations higher pitch than you can hear can put too much power into the tweeters of these.