Distortion at higher volumes.

[Maximo]

I am guessing amp (HK AVR25) but I am curious to your oppion about hte following. I fired up my garage system for the first time in a while and at louder volumes I encountered unwanted audible distortion. The Speakers are some old PA speakers Matt B sent me. I tried two different sources with the same results. What do you think?

 

[Flint]

Probably maxing outthe system (amp or speakers or both) as well as saturating the room (acoustic saturation).

 

[DIYer]

Severe reverberation may sound like distortion. At least that's what I've experienced before.

BTW, Matt didn't charge you for those, did he?

 

[Maximo]

Sexual Favors only.

I don't think it is acoustical saturation as I have heard cleaner/higher volume in my garage before. And let me say that it wasn't THAT high.

 

[Flint]

Then it is either the amp or the speakers reaching the limit of their capabilities.

 

[MatthewB]

Maximo, if I recall (and my mind is getting hazy in my old age) but those have the 15" woofers correct (or is it the 12's) anyway if it is the 15" those require a tad bit of power to drive when played loud. I recall those could only handle 100 watts and were 84db @1 watt/1 meter. So your HK amp may not have enough juice to drive to insane levels with those huge woofers. You may want to buy a stereo amp to drive those monsters.

Another thing to check are those Piezo tweeters. I recall that I had two pairs of those speakers and I gave you the good set and sold the other pair to a pawn shop and it had a faulty tweeter which would distort. They can be found online and are really cheap. Either that or turn it down you young whimper snapper.

Amd about those "sexual favors" I'm still waiting there Big Boy. bscene-birdiedoublered:

 

[Flint]

Most decent PA speakers typically have a very high sensitivity and generate considerably more output per watt than home speakers. What kind are these to be so terribly inefficient???

 

[yromj]

Maximo, if I recall (and my mind is getting hazy in my old age) but those have the 15" woofers correct (or is it the 12's) anyway if it is the 15" those require a tad bit of power to drive when played loud. I recall those could only handle 100 watts and were 84db @1 watt/1 meter. So your HK amp may not have enough juice to drive to insane levels with those huge woofers. You may want to buy a stereo amp to drive those monsters.

A PA speaker that's only capable of 104dB at 1m? As they say here in the south, "Summin' ain't rat."

I'm also suspicious of room saturation due to the presence of things like a concrete slab.

John

 

[Maximo]

I still don't think I am playing them loud enough for room saturation. Maybe I am wrong. I would switch sources and amps and see what happens.

 

[Flint]

What are the speakers?

There a tons of really truly crappy PA speakers out there which look loud but are indeed not loud at all. I've been in pawn shops and lower end pro music stores and have seen speakers which look to be serious PA speakers but cost WAY too little to be convincing. A 15" driver and a horn does not inherently make for loud.

 

[Maximo]

They have no name on them. I rememebr driving them harder than this. At least I think I do. I will do some A/Bing acrosss the board for the equipment and see what I come up with.

 

[DIYer]

Do you have SPL meter and pink tone source you can play? If you do, let us know at what db it starts to distort from 1m (3.28 ft).

 

[MatthewB]

I think they were the Optimus ST-15 or something like that, but I recall pretty inefficient.

 

[MatthewB]

All they had were a Piezo 1" horn tweet and 15" bass driver I could be wrong on the db (it has been years)

 

[MatthewB]

Fro some reason the Optimus ST-1015 is also ringing a bell with me.

 

[Maximo]

I think that is it. I am finally back in town. Once I get my LR set up I will start working on these.