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Question on mid-horns [message #15850] Mon, 15 December 2003 21:20 Go to next message
hurdy_gurdyman is currently offline  hurdy_gurdyman
Messages: 416
Registered: May 2009
Illuminati (1st Degree)
When listening to my Heresy 1's, I sometimes hear what I can best describe as a "break-up" on some complex music and pushed vocals. This is in the mid-horns mid to upper range. I haven't been able to determine if this is the horn, the recordings, or something else.
Any thoughts on this? Is this typical of horns? Perhaps I need better equipment up front? I'm using a nice running Scott LK-48-B integrated tube amp from 1964 to power them. It's not a big problem most times, but sometimes it's irritating.

Dave :^/

Re: Question on mid-horns [message #15852 is a reply to message #15850] Mon, 15 December 2003 21:55 Go to previous messageGo to next message
Wayne Parham is currently offline  Wayne Parham
Messages: 18669
Registered: January 2001
Illuminati (33rd Degree)
Hi Dave!

The description you give makes me think of the sound of a compression horn that is pushed past its limits. They get rough when overpowered or used at too low frequency.

Of course, the source signal can do this too. When the amp clips, the sound that results is similar. And I've heard it on some 60's and 70's recordings. A great example is "Dear Diary" from the Moody Blues album, "Threshold of a Dream." You'll hear this sound on the best system in the world. Ironically, it sounds better on a mediocre system.

The engineer must have overdriven the panel or tape when he mixed down the master, because it isn't present on the greatest hits album, "This is the Moody Blues." I notice that the effects vocal is reduced on this song and on the poem "In the Beginning," also originally from "Threshold of a Dream." So I guess the mix-down engineer caught it second time around.

Wayne

Re: Question on mid-horns [message #15854 is a reply to message #15852] Mon, 15 December 2003 22:23 Go to previous messageGo to next message
hurdy_gurdyman is currently offline  hurdy_gurdyman
Messages: 416
Registered: May 2009
Illuminati (1st Degree)
Hi Wayne,
I don't think I'm overdriving the Heresy's, as most of my listening is in the upper 70's to lower 80's dB range. The distotion I am hearing is on a lot of recordings. Is it possible that the horns may have been damaged from misuse by the previous owner? Do compression drivers wear out when used hard?

Dave


Re: Question on mid-horns [message #15855 is a reply to message #15854] Mon, 15 December 2003 22:48 Go to previous messageGo to next message
Wayne Parham is currently offline  Wayne Parham
Messages: 18669
Registered: January 2001
Illuminati (33rd Degree)
Maybe you're on to something. All machines have a life-span, and all can be damaged. Loudspeakers are constantly moving when in use, and some parts are prone to wear out after time. The surround will eventually fatigue from steady use, even if the device is never used beyond its operating limits. So you might want to check them to see if they have been damaged or fatigued.

Re: Question on mid-horns [message #15856 is a reply to message #15855] Tue, 16 December 2003 00:15 Go to previous messageGo to next message
hurdy_gurdyman is currently offline  hurdy_gurdyman
Messages: 416
Registered: May 2009
Illuminati (1st Degree)
Wayne,
Any ideas on how to tell if they are damaged from examining them?

The reason I suspect they had a hard life is I bought them at a yard sale from a collage student who said they belonged to her boyfriend (only $5.00!). They look awful, like maybe they were the offical frat party speakers for the last 20 years or so.

Thanks for the help.

Dave

Re: Question on mid-horns [message #15857 is a reply to message #15856] Tue, 16 December 2003 00:53 Go to previous messageGo to next message
Wayne Parham is currently offline  Wayne Parham
Messages: 18669
Registered: January 2001
Illuminati (33rd Degree)
You might want to confirm that it isn't the amplifier or crossover before concentrating on the compression driver. Use a known-good amp and crossover so you can be sure that isn't the cause. Once you've isolated the trouble to the driver, you can repair it. But it would be nice if you found out your problem was just a $5.00 capacitor.

So I'd make sure it wasn't something else first, and then once I was sure the problem was the midrange horn, I'd remove the midrange horn, open it up and and inspect the diaphragm. If the surround is cracked, you'll be able to see it.

If you're uncomfortable taking the compression driver apart, perhaps take it to a repair shop for inspection.

Re:mid-horns - maybe try a test cd? [message #15858 is a reply to message #15850] Tue, 16 December 2003 06:15 Go to previous messageGo to next message
wunhuanglo is currently offline  wunhuanglo
Messages: 912
Registered: May 2009
Illuminati (2nd Degree)
I'm thinking if you can "sweep" the speakers it will reveal mechanical damage to the drivers because it will tend to be resonant. At least that's what I'd try first.

Re: Question on mid-horns [message #15860 is a reply to message #15854] Tue, 16 December 2003 08:26 Go to previous messageGo to next message
HenryW is currently offline  HenryW
Messages: 44
Registered: May 2009
Baron
Dave - I cannot speak to heart of your problem than to say that I do not have such a consistent problem with my Heresy. Over the years they have been pushed in all sorts of directions and over 15 sources have been used.

I did experience something that sounds like your issue with the tweets on my older Heresy and after much wrangling found that my CD deck was the culprit. Without researching diligently, when the problem first happened it was only apparent on the 80 Heresy, not on the 87 HII. As it progress the HII started to have the same symptoms.

Not much help on specifics...

Re: Question on mid-horns [message #15861 is a reply to message #15857] Tue, 16 December 2003 09:36 Go to previous messageGo to next message
hurdy_gurdyman is currently offline  hurdy_gurdyman
Messages: 416
Registered: May 2009
Illuminati (1st Degree)
>You might want to confirm that it isn't the amplifier or crossover before concentrating on the compression driver. Use a known-good amp and crossover so you can be sure that isn't the cause. Once you've isolated the trouble to the driver, you can repair it. But it would be nice if you found out your problem was just a $5.00 capacitor.

So I'd make sure it wasn't something else first, and then once I was sure the problem was the midrange horn, I'd remove the midrange horn, open it up and and inspect the diaphragm. If the surround is cracked, you'll be able to see it.

If you're uncomfortable taking the compression driver apart, perhaps take it to a repair shop for inspection.

Re:mid-horns - maybe try a test cd? [message #15862 is a reply to message #15858] Tue, 16 December 2003 09:38 Go to previous messageGo to previous message
hurdy_gurdyman is currently offline  hurdy_gurdyman
Messages: 416
Registered: May 2009
Illuminati (1st Degree)
Good idea. I have Stereophile's test disc 1 and 2. One of them has a frequency sweep, if I recall correctly.

Dave

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