Speaker Repair

Rate this item
(0 votes)
November 26th Written by 

Loudspeaker repair is generally quite simple if you have the right replacement woofer, midrange or tweeter and a soldering iron on hand but first we should say a few words about why speakers fail. 

Whether it is hifi stereo, home theater, sound reinforcement, automotive or PA loudspeakers, the most common cause of failure is too much of the wrong kind of power. Not too much available power. 

When overdriven, an amplifier “clips” the top off the sine waves it is trying to produce because it reaches its maximum voltage ceiling. This clipping effect produces a large amount of high frequency energy which goes straight to the tweeter. Tweeter burnout is the number one type of loudspeaker failure. 

A 200w per channel amp is less likely to fry tweeters than a 50w amp because it has so much more headroom and can produce a cleaner wave at higher power. 

Low power amplifiers can burn out any tweeter and low power amplifiers are more likely to be overdriven. If you hear the sound becoming hard or distorted, that is the sound of clipping. Back off!! 

The next is woofer burnout or overdriving which causes scaping or rattling. Crossover components rarely fail except in extreme cases. If you can see the woofer cones moving, they are being driven fairly hard. Use common sense. 

Once you have diagnosed the problem, you can call the dealer or service centre and decide if the speaker is worth repairing. 

If you can’t get any support or if you would like to tackle the repair yourself, here are some steps to consider. 

1. Pull out the defective driver. 

2. Do the battery test on it. A volt meter impedance tests works as well. Don’t be alarmed if your 8 Ohm speaker tests as low as 4.5 Ohms, that is a dc reading and the 8 Ohms is only nominal. 

3. If it is “dead”, time to track down a replacement. 

4. If it is live, then the issue is inside the enclosure (very rare) and you’ll have to pull the crossover.

A FEW TRICKS

How do you know your speaker has failed? Could it be a connection? Apply the voltage of a small 9 volt or smaller battery across the binding posts (with the amplifier speaker cables disconnected) and see if you get a lick or pop. If you do, the speaker is working to some degree. Check your wiring to the amp. 

If there is no sound or distorted sound, press gently in on the cone of the woofer with your fingers spread across the diaphragm. If it doesn’t move, it is fried with the voice coil melted and jammed in the magnetic gap. If it does move but scraping and scratching is audible, it may not be as bad but it probably indicates the driver still must be replaced. 

If the scraping goes away when you push on only one side of the cone, a mickey mouse fix is possible if you can’t get a replacement woofer. If this is a nothing to lose situation, take a piece of masking tape and stretch it over the baffle and over the side of the cone so the tape slightly presses on the rubber or foam surround. This can equate to your finger pressure. If this works, you can try something more permanent with duct tape. 

Note this is a last resort and the frequency response of the speaker will be affected. Also, taking off the tape may well rip the woofer surround. 

If it is difficult to pry the woofer or tweeter out of the baffle without damaging it, here is an option.  

Find a screw slightly larger than the screw hole on the frame of the driver. Turn the screw into this so it becomes jammed. No need to really force it in, just make it snug. 

Take a small wood block, place it on the baffle beside the screw and use a hammer to pull up the on the head of the screw. The driver should come up with it. 

Repairing Newform Research speakers is a little different. If a Ribbon fails, call us first. Absolutely do not take off the faceplate as this will result in further damage. Our Ribbons are extremely robust so failure is very unlikely. Our Ribbons require no maintenance. If you detect a problem of some kind, if the Ribbons are making sound, they are almost certainly working to spec. Look elsewhere for the problem and talk to us! 

Where can you get replacement speakers? The number one source in the USA is Madisound (www.madisound.com ) who is also a large supplier of loudspeaker kits for DIY projects. 

In Canada, Solen Electronics is the source (www.solen.ca). 

Loudspeakers Unsurpassed in Soundstage, Transparency, Detail and Dynamics in High End Stereo and Home Theater Systems 

 

Read 3989 times Last modified on Wednesday, 25 December 2013 16:17
Published in Audio Planet