Mackie HR824 Woofer Problem

Archived from groups: rec.audio.pro (More info?)

My HR824's have worked well for about 4 years. Recently, both speakers
have had the woofer cut out entirely. I found that cranking the volume for
a moment or two seemed to "unstick" the woofer and get it going again. (As
the volume is cranked, the woofer emits bursts of sound, as if struggling
to come on, hence my description of "unsticking." )

Anyway, I was able to get a spare woofer off ebay for $30, so I replaced
the woofer that had the problem more frequently. As soon as I put the new
woofer in, it started "sticking" but a shot of high volume got it going
right away. (

Because the problem is so intermittent (and the speakers are out of
warranty) I haven't brought them to my local Mackie repair joint. But that
might be the next step, unless anyone has some insight into the problem?
It seems the woofer may not even be the root of the problem.

Incidentally, I noticed some differences between the old woofer and the
replacement. I'll probably check with Mackie, but here are the details in
case anyone knows about this.

Old woofer marked:
490-001-00 2
04 ‡ 811

New woofer marked:
490-001-00
04 ‡ 703

Which suggests the "new" woofer may in fact be older, due to the lower
part numbers? Also, the "old" woofer had an additional magnet
(doughnut-shaped) epoxied to the back of the speaker. The "new" woofer
lacks this magnet. There's a definite difference to the sound; the bass is
not as strong on the "new" speaker. (By changing the bass response setting
on the back, I was able to get the bass closer to the other speaker.)

Perhaps Mackie's parts department will be willing to sell the magnet--but
of course they're not open at the moment. Does anyone know the details on
the speaker differences? Was the additional magnet a "retrofit" or
something like that?

--
Jedd Haas - Artist
http://www.gallerytungsten.com
http://www.epsno.com

Archived from groups: rec.audio.pro (More info?)

In article <cpfha0$6le$1@panix1.panix.com>, kludge@panix.com (Scott
Dorsey) wrote:

> Jedd Haas <jnh@epsno.com> wrote:
> >My HR824's have worked well for about 4 years. Recently, both speakers
> >have had the woofer cut out entirely. I found that cranking the volume for
> >a moment or two seemed to "unstick" the woofer and get it going again. (As
> >the volume is cranked, the woofer emits bursts of sound, as if struggling
> >to come on, hence my description of "unsticking." )
>
> When this happens, does disconnecting the woofer from the amp fix the
> problem? If so, it's the amp throwing out major DC offset. If not, the
> woofer cone is mechanically sticking.

I'm not following you here; if I disconnect the woofer, how will I know if
the problem is fixed? Are you suggesting putting in another woofer? If
not, won't it be bad for amp to run it with no speaker? Or do you mean to
disconnect the woofer, then reconnect it to see if it works again
immediately?

> >Anyway, I was able to get a spare woofer off ebay for $30, so I replaced
> >the woofer that had the problem more frequently. As soon as I put the new
> >woofer in, it started "sticking" but a shot of high volume got it going
> >right away. (
>
> This sounds to me like a DC offset problem. Try running it on the bench
> with the woofer removed, make it stick, then disconnect it from the amp
> and see if you don't have an amp problem.

Again--if the woofer is removed, how do I make it stick or even know it's
sticking? The problem is intermittent woofer cut-out. I'm not sure how to
get it to stick, it does it on its own at random intervals (sometimes days
apart).

Have you seen DC offset problems on the HR824's before? If so, is the fix
(typically) a few parts, or is it major?

--
Jedd Haas - Artist
http://www.gallerytungsten.com
http://www.epsno.com

Archived from groups: rec.audio.pro (More info?)

Jedd Haas <jnh@epsno.com> wrote:
>In article <cpfha0$6le$1@panix1.panix.com>, kludge@panix.com (Scott
>Dorsey) wrote:
>
>> Jedd Haas <jnh@epsno.com> wrote:
>> >My HR824's have worked well for about 4 years. Recently, both speakers
>> >have had the woofer cut out entirely. I found that cranking the volume for
>> >a moment or two seemed to "unstick" the woofer and get it going again. (As
>> >the volume is cranked, the woofer emits bursts of sound, as if struggling
>> >to come on, hence my description of "unsticking." )
>>
>> When this happens, does disconnecting the woofer from the amp fix the
>> problem? If so, it's the amp throwing out major DC offset. If not, the
>> woofer cone is mechanically sticking.
>
>I'm not following you here; if I disconnect the woofer, how will I know if
>the problem is fixed? Are you suggesting putting in another woofer? If
>not, won't it be bad for amp to run it with no speaker? Or do you mean to
>disconnect the woofer, then reconnect it to see if it works again
>immediately?

Okay, I am assuming that the woofer is stuck at one end of travel, right?
If you unplug it, does it return to the zero point or does it stay stuck?

OR it it acting like a bad connection to the voice coil, where tapping on
the cone with your fingers and wiggling the tinsel wires temporily fixes
the problem?
--scott


--
"C'est un Nagra. C'est suisse, et tres, tres precis."

Archived from groups: rec.audio.pro (More info?)

Mackie used to be very good about supporting their products, even out
of warranty.

Al

On Sat, 11 Dec 2004 13:04:31 -0600, jnh@epsno.com (Jedd Haas) wrote:

>My HR824's have worked well for about 4 years. Recently, both speakers
>have had the woofer cut out entirely. I found that cranking the volume for
>a moment or two seemed to "unstick" the woofer and get it going again. (As
>the volume is cranked, the woofer emits bursts of sound, as if struggling
>to come on, hence my description of "unsticking." )
>
>Anyway, I was able to get a spare woofer off ebay for $30, so I replaced
>the woofer that had the problem more frequently. As soon as I put the new
>woofer in, it started "sticking" but a shot of high volume got it going
>right away. (
>
>Because the problem is so intermittent (and the speakers are out of
>warranty) I haven't brought them to my local Mackie repair joint. But that
>might be the next step, unless anyone has some insight into the problem?
>It seems the woofer may not even be the root of the problem.
>
>Incidentally, I noticed some differences between the old woofer and the
>replacement. I'll probably check with Mackie, but here are the details in
>case anyone knows about this.
>
>Old woofer marked:
>490-001-00 2
>04 ‡ 811
>
>New woofer marked:
>490-001-00
>04 ‡ 703
>
>Which suggests the "new" woofer may in fact be older, due to the lower
>part numbers? Also, the "old" woofer had an additional magnet
>(doughnut-shaped) epoxied to the back of the speaker. The "new" woofer
>lacks this magnet. There's a definite difference to the sound; the bass is
>not as strong on the "new" speaker. (By changing the bass response setting
>on the back, I was able to get the bass closer to the other speaker.)
>
>Perhaps Mackie's parts department will be willing to sell the magnet--but
>of course they're not open at the moment. Does anyone know the details on
>the speaker differences? Was the additional magnet a "retrofit" or
>something like that?

Archived from groups: rec.audio.pro (More info?)

In article <cpgd5002p9r@enews4.newsguy.com>,
Bob Cain <arcane@arcanemethods.com> wrote:

> Jedd Haas wrote:
> > My HR824's have worked well for about 4 years. Recently, both speakers
> > have had the woofer cut out entirely. I found that cranking the volume for
> > a moment or two seemed to "unstick" the woofer and get it going again. (As
> > the volume is cranked, the woofer emits bursts of sound, as if struggling
> > to come on, hence my description of "unsticking." )
>
> Check the bass rolloff switches in back. They can get
> intermittant and "microphonic" in a raggedy sort of way.
>
>
> Bob

To the OP: While you're playing with switches, try reseating any
connectors/switch and switch back any switches/hit any buttons and bring
them back to the position they were in.

I'm with the camp that its something in the amp. Usually speakers either
work or don't work.

--
Cyrus

*coughcasaucedoprodigynetcough*

Archived from groups: rec.audio.pro (More info?)

In article <waxurcarot-C1BB1A.11482312122004@comcast.dca.giganews.com> waxurcarot@normendy.com writes:

> Why not just measure the DC component, once the woofer is stuck?

If the problem is actually DC coming out the speaker output, you don't
want to apply that to a might-still-be-good speaker any longer than
necessary or it may no longer be still-good.

It's still not clear if the woofer is actually physically stuck - like
when it moves from its centered position, it stays put after the
signal and power is removed (that's bad) or if it moves off center
when power is applied and goes back to center when power is removed
(that's an amplifier problem). Or even if "stuck" means that it simply
stops working and we have no information at all about the actual
motion of the cone.

That's the problem with having an idea of what's wrong and not being
able to see the patient.


--
I'm really Mike Rivers (mrivers@d-and-d.com)
However, until the spam goes away or Hell freezes over,
lots of IP addresses are blocked from this system. If
you e-mail me and it bounces, use your secret decoder ring
and reach me here: double-m-eleven-double-zero at yahoo

Archived from groups: rec.audio.pro (More info?)

In article <waxurcarot-C1BB1A.11482312122004@comcast.dca.giganews.com>,
Hannibul Artese <waxurcarot@normendy.com> wrote:
>In article <cpfuhs$isu$1@panix2.panix.com>,
> kludge@panix.com (Scott Dorsey) wrote:
>
>> Okay, I am assuming that the woofer is stuck at one end of travel, right?
>> If you unplug it, does it return to the zero point or does it stay stuck?
>>
>> OR it it acting like a bad connection to the voice coil, where tapping on
>> the cone with your fingers and wiggling the tinsel wires temporily fixes
>> the problem?
>
>Why not just measure the DC component, once the woofer is stuck?

Just because that seems like more work than disconnecting the plug on
the back. But yes, that would tell you what is going on just as well.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

Archived from groups: rec.audio.pro (More info?)

"Jedd Haas" <jnh@epsno.com> wrote in message
news:jnh-1112041304320001@192.168.0.101...
> My HR824's have worked well for about 4 years. Recently, both speakers
> have had the woofer cut out entirely. I found that cranking the volume for
> a moment or two seemed to "unstick" the woofer and get it going again. (As
> the volume is cranked, the woofer emits bursts of sound, as if struggling
> to come on, hence my description of "unsticking." )
>
> Anyway, I was able to get a spare woofer off ebay for $30, so I replaced
> the woofer that had the problem more frequently. As soon as I put the new
> woofer in, it started "sticking" but a shot of high volume got it going
> right away. (
>
> Because the problem is so intermittent (and the speakers are out of
> warranty) I haven't brought them to my local Mackie repair joint. But that
> might be the next step, unless anyone has some insight into the problem?
> It seems the woofer may not even be the root of the problem.
>
> Incidentally, I noticed some differences between the old woofer and the
> replacement. I'll probably check with Mackie, but here are the details in
> case anyone knows about this.
>
> Old woofer marked:
> 490-001-00 2
> 04 ‡ 811
>
> New woofer marked:
> 490-001-00
> 04 ‡ 703
>
> Which suggests the "new" woofer may in fact be older, due to the lower
> part numbers? Also, the "old" woofer had an additional magnet
> (doughnut-shaped) epoxied to the back of the speaker. The "new" woofer
> lacks this magnet. There's a definite difference to the sound; the bass is
> not as strong on the "new" speaker. (By changing the bass response setting
> on the back, I was able to get the bass closer to the other speaker.)
>
> Perhaps Mackie's parts department will be willing to sell the magnet--but
> of course they're not open at the moment. Does anyone know the details on
> the speaker differences? Was the additional magnet a "retrofit" or
> something like that?
>
> --
> Jedd Haas - Artist
> http://www.gallerytungsten.com
> http://www.epsno.com

Sounds like there is some cold solder joint on the PCB in the amp
have a look for something heavy in there that has come loose
do the pencil probe to see if wiggling components makes anything happen.

Doug

Archived from groups: rec.audio.pro (More info?)

Thanks for all your replies. I'm leaning toward the flaky connection
theory. (I had a similar problem about six months back that was solved by
switching from the XLR inputs to the TRS inputs.)

So far it hasn't cut out again, so perhaps it was the bass switch or the
wires connecting to the speaker lugs.

--
Jedd Haas - Artist
http://www.gallerytungsten.com
http://www.epsno.com