Blown horns or crossovers &$#&***$

[JLNorthGA]

The speakers are the ones up on the walls. Didn't really sound right at the last concert - now we know why.

They are a pair of older Nady PS115 speakers - evidently this speaker has a history of having the horns blow (pun NOT intended). This week we had time to really listen to them - they have no highs worth speaking of - probably just what the crossover allocates to the 15" speakers. I hear the bass and the 15" speakers. I hear no highs.

I will have to pull them down and give them a look see. Fortunately the only thing we have going this weekend is a puppet show. He has a soundtrack - but no real demanding music.

Anyone have any quick diagnostic tests to determine if it is the crossovers or the horn drivers?

 

[wolfman005]

I'd be interested in learning too. Our school has some older speakers that the high end is blown out of, and it would be really beneficial if we could use them.
Also to take it a step further, what do you do to prevent it from happening again? We already have limiters on out amps and signal processor. Is there something more we can do?

 

[Les]

The speakers are the ones up on the walls. Didn't really sound right at the last concert - now we know why.

They are a pair of older Nady PS115 speakers - evidently this speaker has a history of having the horns blow (pun NOT intended). This week we had time to really listen to them - they have no highs worth speaking of - probably just what the crossover allocates to the 15" speakers. I hear the bass and the 15" speakers. I hear no highs.

I will have to pull them down and give them a look see. Fortunately the only thing we have going this weekend is a puppet show. He has a soundtrack - but no real demanding music.

Anyone have any quick diagnostic tests to determine if it is the crossovers or the horn drivers?

My educated guess would be to test the continuity of the pins or posts at the horns (while disconnected). Not sure about the crossover. Luckily if it is the horns, diaphragms are easy to replace if you can find them.

I used to work at a theatre where we thought a visiting sound tech had blown the horns, but it turned out that the amp was faulty.

Here's the thread, which I unfortunately never updated.
http://www.controlbooth.com/forums/sound-music-intercom/2049-what-do-you-do-when-mains-blown.html

 

[neotrotsky]

Blowing the horns out of Nady speakers could only improve their sound quality :neutral:

That being said, this gives you a great chance to save some cash and replace the speaker horns with something of better quality. And, I have seen some sweet deals around the net for horns lately. I would check to see if your rig is putting out a clean consistent power feed after the crossover, and then compare that number to the rating of the horns. Being Nady, it's not unusual to have them over-speced and to find out you have actually been over driving them this whole time without being aware

 

[museav]

Semantics, but I found it hard to believe the horns failed, however the compression drivers on the horns may have.

You could take apart the speaker, disconnect the HF compression drivers and measure the resistance of the drivers. Since you are measuring simple resistance rather than impedance it may be some odd number but it should give some idea if the drivers are open (infinite resistance) or shorted (zero resistance).

But before doing that you might consider what you would do if the drivers have failed. If it is pretty clear that the speakers have a problem, a tone sweep or similar should be easy to find online and running that through the system should make that obvious, would you try to replace the drivers or crossover or would you replace the speakers? No sense spending a lot of effort on determining if it is the crossover or driver if either failing would result in new speakers.

I'd be interested in learning too. Our school has some older speakers that the high end is blown out of, and it would be really beneficial if we could use them.
Also to take it a step further, what do you do to prevent it from happening again? We already have limiters on out amps and signal processor. Is there something more we can do?

Make sure the limiters are properly set for your speakers and amplifiers. Also realize:

• Many limiters will let a little bit of a peak through before they react. The hard cough, the dropped mic, etc. may still have the leading edge get through.
• Peak limiters may address peaks in the level but do not necessarily affect high long term levels that can lead to thermal failures.
• Power or averaging limiters may look at the levels over a longer period but not try to stop peaks.

 

[JLNorthGA]

Semantics, but I found it hard to believe the horns failed, however the compression drivers on the horns may have.

You could take apart the speaker, disconnect the HF compression drivers and measure the resistance of the drivers. Since you are measuring simple resistance rather than impedance it may be some odd number but it should give some idea if the drivers are open (infinite resistance) or shorted (zero resistance).

But before doing that you might consider what you would do if the drivers have failed. If it is pretty clear that the speakers have a problem, a tone sweep or similar should be easy to find online and running that through the system should make that obvious, would you try to replace the drivers or crossover or would you replace the speakers? No sense spending a lot of effort on determining if it is the crossover or driver if either failing would result in new speakers.


Make sure the limiters are properly set for your speakers and amplifiers. Also realize:

• Many limiters will let a little bit of a peak through before they react. The hard cough, the dropped mic, etc. may still have the leading edge get through.
• Peak limiters may address peaks in the level but do not necessarily affect high long term levels that can lead to thermal failures.
• Power or averaging limiters may look at the levels over a longer period but not try to stop peaks.

Interesting that you mentioned "tone sweep" - because that's one of the things we noticed. We were using a pink noise generator and saw that there were no highs. We talked to the Nady technical support (the lack of scintillating intellect was obvious) - and they did suggest that the drivers were blown - and that we could go online and search for Piezo drivers and find them for less than $10 - or we could buy theirs. I'll be taking them down and doing the diagnosis this coming week.

 

[Aman121]

Even though the parts are cheap, it might be time to consider upgrading the speakers completely now that you have an excuse to. Tell your board that they are shot and to budget 500-1k for new speakers. I really enjoy hearing about your venue, and it seems that you have a variety of music and theater acts come through. Better sound would undoubtedly increase your marketability. Assuming that your current setup of the 2 15s on stands worked satisfactorily for you, a new pair of passive 15s or 12s to be installed as a direct drop in seems like a viable solution. Maybe look for used speakers locally, the JBL sr series was quite nice, and can usually had for a reasonable price used. Or look into new stuff, the EV sx300es are great sounding and will probably work great for you.

 

[JLNorthGA]

Just purchased a new pair of JBL speakers - JRX115. They have 1000 W peak power and 250 W continuous.

These should work as the new main speakers. We'll use our old Yamaha speakers (400 W peak/200 W continuous) as fill speakers and the other old set of Nady PS115 as fill speakers.

 

[Aman121]

Just purchased a new pair of JBL speakers - JRX115. They have 1000 W peak power and 250 W continuous.

These should work as the new main speakers. We'll use our old Yamaha speakers (400 W peak/200 W continuous) as fill speakers and the other old set of Nady PS115 as fill speakers.

Besides the shiny JBL logo, you really didn't upgrade to much unfortunatly. The jrx series really isint that great and can be thrown in the same pile as seismic/Pyle/Nady ect. Your really buying the name more than anything. But there are worse sounding speakers out there, and they can sound half decent with a bit of eq. Hopefully they will work a bit better than the nadys, they do at least have a compression horn driver instead of a piezo tweeter which helps.

 

[neotrotsky]

At least with the JBL you get a modicum of durability. The Chinese brand speakers off Amazon are always questionable in longevity as they are poor in quality. If they can get the job done consistently then you can trade for quality with a bit of skill in mixing.

 

[JLNorthGA]

At least with the JBL you get a modicum of durability. The Chinese brand speakers off Amazon are always questionable in longevity as they are poor in quality. If they can get the job done consistently then you can trade for quality with a bit of skill in mixing.

We really don't need much in terms of speakers. Quite frankly, a decent 100 W might system work well for the house as the acoustics are reasonably good. A reasonable singer who can project does not need amplification. You don't really need to put microphones on an acoustic piano, brass, saxophones, etc.

As an example, I used four monitor speakers (75 W RMS, 150 W peak) - for the last dance recital. They wanted control of their music from their laptop. So I set up the four monitor speakers with two behind the back curtain and the other two in the wings. I used a 100 W RMS at 8 ohms amplifier. The sound was reasonably clear (even over the clogging!) and sounded good. It couldn't be mixed - but it was a recorded track and didn't really need to be mixed.

We typically are at 1/4 level using our GX5 amplifier for the main speakers (the soon to be replaced Nady speakers). The speakers under the stage are a somewhat different story - we're trying to boost the low frequencies.

More power isn't necessarily needed - just good control.

 

[JLNorthGA]

Update on the blown Nady tweeters.

I got them down from the wall after we received the JBL speakers. The tweeters are pieces of garbage. I don't have a problem with the horns being plastic - that is a reasonable choice. When I put a multimeter on the leads to the tweeter, there was a spotty infinite resistance. When I unscrewed the back of the driver out of curiosity, I discovered why the infinite resistance. The lead tabs have wires which lead to the coil and the coil has wires to the piezo disk. The wires to the disk were quite flimsy and evidently break reasonably easily. The wire on one side of the disk broke right near the solder joint. It had intermittent contact which probably happened as vibration moved the housing.

Next question - to repair or not to repair?
I can get a new horn and driver for ~$37 per unit - this is replacement with a higher quality horn and driver rather than the Nady replacement. The 15" speaker and crossover are in good shape as in the speaker case. I figure the cost of repair is on the order of 13% (or less) the cost of a new speaker that would be better than the Nady. The new hybrid speaker would probably be of better sound quality - at least in the high end frequencies - than the old Nady.

 

[museav]

My usual caution on these situations is that the crossover and drivers work together as a circuit so if you change drivers you potentially change that circuit. How a different driver and horn will work with the current crossover and LF driver goes beyond just matching the HF driver nominal impedance and sensitivity so while a different driver and horn might be worth trying, you might want to try if for one speaker first.

 

[FMEng]

Piezos are very different than compression drivers in terms of their impedance. Therefore, the existing crossover isn't likely to be compatible with a compression driver. Unless you want a bigger project of trying to match a new horn with a new crossover to the woofer, you'd be better off replacing with a factory replacement.

 

[JLNorthGA]

I'll give it a try - if it works, I'll buy more drivers and horns. If it doesn't work, I can build some new crossovers.

 

[JLNorthGA]

Update - received a driver and horn from Parts Express (really good service!) after picking a driver that had the same wattage and impedance. Replaced the driver and horn in the Nady. Tested it. WOW! What a difference.

The driver/horn on the Nady was essentially one piece. Really light weight. The new driver and horn are two pieces. The Pyle driver is quite heavy. Adds several pounds to the speaker. Tested the speaker - makes a big difference. The highs are crisper and more powerful than in the remaining intact Nady. So basically for about $37 each, I can replace the drivers. I think that it is a reasonable cost - much less than the cost of a new speaker.

This will work as an interim solution until we can afford new subwoofers and fill speakers.