Discussion:
How much power to Yorkville LS1208
(too old to reply)
Tom Hole
2004-08-11 11:48:42 UTC
Permalink
I have 2 Yorkville LS1208's. Yorkville lists them as 1200W program. As you
know, I have been driving them both with a single RMX2450 @ 1200W each. I
am putting a 2450 on one and a Behringer 2500 on the other which will be
1500W each. Over on the Harmony-Central board, they say that's nuts,
waaaayyy too much power. Whadyall think? I plan to use the limiter in the
01v96 to keep the amps out of clipping. I DO NOT want to blow the 1208's.
They are doing great with whatever the single 2450 was providing before, so
I would like to keep it at that.

Thanks in advacne,

Tom
Mike
2004-08-11 15:00:16 UTC
Permalink
Post by Tom Hole
I have 2 Yorkville LS1208's. Yorkville lists them as 1200W program.
As you know, I have been driving them both with a single RMX2450
@ 1200W each. I am putting a 2450 on one and a Behringer 2500
on the other which will be 1500W each. Over on the Harmony-
Central board, they say that's nuts, waaaayyy too much power.
Whadyall think?
You'll see a litle improvement in the output, but not a lot. The built
in circuit breaker will pretect the driver from too much power, but not too
much voltage (over extension) so watch the peak levels your sending the
subs. Also, watch your tuning. Make sure you're not trying to run freqs
that are below the tuning of the cabinet.
Post by Tom Hole
I plan to use the limiter in the 01v96 to keep the amps out of clipping.
That's good.
Post by Tom Hole
I DO NOT want to blow the 1208's.
We've got 48 ES1004/LS1004 cabinets between our portable and installed
rigs running 2000W per cabinet. We've only had one driver quit on us. Not
because it was blown, but because the cabinet got dropped and the magnet
shifted and messed up the gap.
Post by Tom Hole
They are doing great with whatever the single 2450 was providing before, so
I would like to keep it at that.
OK, if they're working fine, why the change??

Mike Borkhuis
Audio Images Sound & Lighting, Inc
www.audioimagesonline.com
Tom Hole
2004-08-11 23:32:18 UTC
Permalink
Post by Mike
Post by Tom Hole
They are doing great with whatever the single 2450 was providing before,
so
Post by Tom Hole
I would like to keep it at that.
OK, if they're working fine, why the change??
Mike Borkhuis
Audio Images Sound & Lighting, Inc
www.audioimagesonline.com
The cabs were fine, the 2450 was not. My fault, of course, as it was
showing a clip light and I pressed on anyway. I had the built in limiters
engaged and the amp has shut down on me twice. Figured 2 2450's would ease
up on the amps. Just want to make sure there is no failure mode and that
means I need to be more disciplined with the gain structure.

The wise folks on the Harmony Central board are telling me that I should
only give the 1208's 700Watts / cab and that I am an utter moron for driving
them with 1200W let alone 1500W. I have been driving them with the 2450
bridged for almost 3 years with no cab failures. Why the heck would I move
down to 700W / cab? Snitty bunch of folks over there.

Tom
Pooh Bear
2004-08-12 00:35:26 UTC
Permalink
Post by Tom Hole
The cabs were fine, the 2450 was not. My fault, of course, as it was
showing a clip light and I pressed on anyway.
Ok - that means that the 1208s weren't providing the SPL you were looking for
and consequently the amp was clipping.

Your ideal solution would be to use cabs that are more efficient ( dB/W ).
Post by Tom Hole
I had the built in limiters
engaged and the amp has shut down on me twice.
RMXs normally 'shut down' with no leds illuminated in a particularly unhelpful
way. Normally that means the amp has 'thermalled' - i.e. over heated due to
being asked to provide high average power levels.
Post by Tom Hole
Figured 2 2450's would ease up on the amps.
Yup , that will be the case ok. Your SPL won't increase much to talk of though
so you'll still be stuck with lower SPL capability than you apparently really
require.
Post by Tom Hole
Just want to make sure there is no failure mode and that
means I need to be more disciplined with the gain structure.
Your suggested change has no 'failure mode'. You'll certainly stress the amps
less.
Post by Tom Hole
The wise folks on the Harmony Central board are telling me that I should
only give the 1208's 700Watts / cab and that I am an utter moron for driving
them with 1200W let alone 1500W. I have been driving them with the 2450
bridged for almost 3 years with no cab failures. Why the heck would I move
down to 700W / cab? Snitty bunch of folks over there
Since I'm unfamiliar with the cabs, it's hard to comment but be aware that if
*they* think you're pushing the limit at 1200W/cab then you're closer still to
problems @ 1500W/cab - especially so since you're clearly driving them very hard
now and will doubtless drive them harder still when you have the extra power to
hand.


Graham
Tom Hole
2004-08-12 00:41:05 UTC
Permalink
Post by Pooh Bear
Post by Tom Hole
The cabs were fine, the 2450 was not. My fault, of course, as it was
showing a clip light and I pressed on anyway.
Ok - that means that the 1208s weren't providing the SPL you were looking for
and consequently the amp was clipping.
Your ideal solution would be to use cabs that are more efficient ( dB/W ).
Post by Tom Hole
I had the built in limiters
engaged and the amp has shut down on me twice.
RMXs normally 'shut down' with no leds illuminated in a particularly unhelpful
way. Normally that means the amp has 'thermalled' - i.e. over heated due to
being asked to provide high average power levels.
Post by Tom Hole
Figured 2 2450's would ease up on the amps.
Yup , that will be the case ok. Your SPL won't increase much to talk of though
so you'll still be stuck with lower SPL capability than you apparently really
require.
Post by Tom Hole
Just want to make sure there is no failure mode and that
means I need to be more disciplined with the gain structure.
Your suggested change has no 'failure mode'. You'll certainly stress the amps
less.
Post by Tom Hole
The wise folks on the Harmony Central board are telling me that I should
only give the 1208's 700Watts / cab and that I am an utter moron for driving
them with 1200W let alone 1500W. I have been driving them with the 2450
bridged for almost 3 years with no cab failures. Why the heck would I move
down to 700W / cab? Snitty bunch of folks over there
Since I'm unfamiliar with the cabs, it's hard to comment but be aware that if
*they* think you're pushing the limit at 1200W/cab then you're closer still to
now and will doubtless drive them harder still when you have the extra power to
hand.
Graham
Graham,

Here are the specs on the speaker in the 1208:

http://www.bcspeakers.com/compproducts/speakers/18pzb46.htm

700W rms, and they use the double the rms to get program method. There are
2 other guys on that board that are driving their 1208's with a single 2450
each, but they aren't beeing foolhardy with their gain structure clipping
control. My plan is to set up a hard limiter on the 01v96 and keep the amp
out of clipping, period. The best advise I have received through this whole
thread has been:

If you need more SPL, buy more speakers, not bigger amps.

Sage advise, to be sure.

Tom
Pooh Bear
2004-08-12 01:33:30 UTC
Permalink
Post by Tom Hole
Graham,
http://www.bcspeakers.com/compproducts/speakers/18pzb46.htm
700W rms, and they use the double the rms to get program method.
That's a pretty standard convention but not *entirely* 'foolproof' so to speak.
The dynamic range of the amplifier can be compressed as the limiter comes into
action, making the true average power surprisingly close to the rms power ( as
in closer than -3dB ). Depends entirely on the signal of course.
Post by Tom Hole
There are
2 other guys on that board that are driving their 1208's with a single 2450
each, but they aren't beeing foolhardy with their gain structure clipping
control. My plan is to set up a hard limiter on the 01v96 and keep the amp
out of clipping, period.
But how will you set the limiter on the Yammie bearing in mind that these are
just subs ? It's also likely to end up sounding harsh or may hold back on the
power compared to the amp's internal limiter. Trust me, I've designed internal
limiers before and theny are designed to be realively transparent at the edge of
running out of headroom.
Post by Tom Hole
The best advise I have received through this whole
If you need more SPL, buy more speakers, not bigger amps.
Sage advise, to be sure.
Also consider using speakers with a higher dB/W to avoid carting round more cabs
( and weight ) than you'ld like to ! Higher efficiency may be more expensive but
you're saving on the cost of amplifiers and the inconvenience and weight of
multiple cabs.


Graham :-)
Tom Hole
2004-08-12 01:46:39 UTC
Permalink
Post by Pooh Bear
Post by Tom Hole
Graham,
http://www.bcspeakers.com/compproducts/speakers/18pzb46.htm
700W rms, and they use the double the rms to get program method.
That's a pretty standard convention but not *entirely* 'foolproof' so to speak.
The dynamic range of the amplifier can be compressed as the limiter comes into
action, making the true average power surprisingly close to the rms power ( as
in closer than -3dB ). Depends entirely on the signal of course.
Post by Tom Hole
There are
2 other guys on that board that are driving their 1208's with a single 2450
each, but they aren't beeing foolhardy with their gain structure clipping
control. My plan is to set up a hard limiter on the 01v96 and keep the amp
out of clipping, period.
But how will you set the limiter on the Yammie bearing in mind that these are
just subs ? It's also likely to end up sounding harsh or may hold back on the
power compared to the amp's internal limiter. Trust me, I've designed internal
limiers before and theny are designed to be realively transparent at the edge of
running out of headroom.
Post by Tom Hole
The best advise I have received through this whole
If you need more SPL, buy more speakers, not bigger amps.
Sage advise, to be sure.
Also consider using speakers with a higher dB/W to avoid carting round more cabs
( and weight ) than you'ld like to ! Higher efficiency may be more expensive but
you're saving on the cost of amplifiers and the inconvenience and weight of
multiple cabs.
Graham :-)
Graham,

The LS1208 is pretty darned efficient at 105 dB. Of course, Yorkville is
cheating a little in that I think they are including the 1/2 space
adavantage of the horn design. Still, take away that 3db and they are a
respectable 102 dB.

Anyway, I am trying to get a handle on what to use to properly power the
1208's. I have been using the 2450 bridged on them for 3 years and the cabs
are still in one piece. I have been undisciplined and let the 2450 go into
heavy clipping twice and the result has been 1 protect mode with self
recovery and 1 blown fuze. Remove the stupid factor, and I think the
single, bridged 2450 was doing a good job. I just thought that I could
relieve some strain on it by going to 1 per cab. That has elicited many
deriding inputs from folks, most just calling me stupid. Real world users
have illustrated that this works just fine for them and for some reason,
they are not considered idiots, just me.

The recomendation is to use a 3402 on them, one per channel for 800 watts
each. Personally, I think that would leave them underpowered, but
apparently I am an idiot.

I am listening.

TOm
Pooh Bear
2004-08-12 02:55:41 UTC
Permalink
Post by Tom Hole
Graham,
The LS1208 is pretty darned efficient at 105 dB. Of course, Yorkville is
cheating a little in that I think they are including the 1/2 space
adavantage of the horn design. Still, take away that 3db and they are a
respectable 102 dB.
Ok - I was just looking at the driver specs - not the cab as a whole. I'm quite
a fan of horns, so it seems I missed something here.
Post by Tom Hole
Anyway, I am trying to get a handle on what to use to properly power the
1208's. I have been using the 2450 bridged on them for 3 years and the cabs
are still in one piece. I have been undisciplined and let the 2450 go into
heavy clipping twice and the result has been 1 protect mode with self
recovery and 1 blown fuze. Remove the stupid factor, and I think the
single, bridged 2450 was doing a good job.
I would suggest that the problems with the amp are down to powering both cabs in
bridged mode. The RMXs are QSC's least expensive amp and don't ( IMHO ) take
kindly to being driven really hard into the lower impedances - 2 x 8 Ohm cabs
bridged is like driving both channels @ 2 ohms for example. Hence the 'HD'
versions of the RMXs.
Post by Tom Hole
I just thought that I could
relieve some strain on it by going to 1 per cab. That has elicited many
deriding inputs from folks, most just calling me stupid.
Actually it seems perfectly sensible to me - it's like driving each amp @ 4 ohms
where they are much more happy. What was the reason behind the 'stupid' comments
?
Post by Tom Hole
Real world users
have illustrated that this works just fine for them and for some reason,
they are not considered idiots, just me.
Isn't that always the case !
Post by Tom Hole
The recomendation is to use a 3402 on them, one per channel for 800 watts
each. Personally, I think that would leave them underpowered, but
apparently I am an idiot.
My opinion ( and I'm sure it'll be shared by many here ) is that it's daft to
use an 800W rms amp for a 700W rms speaker when the amp has an internal limiter.

I was initally concerned that your initial proposed solution would over power
the cabs with 1500W rms available but the spkr specs' 700W rms suggest that
won't be so, although you should be careful not to drive the amp into clip
regularly.


Cheers, Graham
Dale C
2004-08-12 03:02:19 UTC
Permalink
Post by Tom Hole
The recomendation is to use a 3402 on them, one per channel for 800 watts
each. Personally, I think that would leave them underpowered, but
apparently I am an idiot.
I am listening.
TOm
I have a pair of 218 cabs. They are Peavey DTH with the higher quality BW
speakers in them. These are rated at 2000W rms and 4000W program each cab. I
think I am seriously underpowering them with 1/2 of a QSC 3402 (1100W) on
each of them.

I did try to use the QSC in bridge mode for a night on one cab, and another
QSC on the other. This gave me 3400W for each cab and I think this is where
they are comfortable. I just need another amp to do this on a regular basis.
Not so much for SPL volume, but for the headroom.


Dale
Mike
2004-08-12 04:21:53 UTC
Permalink
Post by Dale C
I have a pair of 218 cabs. They are Peavey DTH with the higher quality
BW speakers in them. These are rated at 2000W rms and 4000W
program each cab. I think I am seriously underpowering them with 1/2
of a QSC 3402 (1100W) on each of them.
I did try to use the QSC in bridge mode for a night on one cab, and
another QSC on the other. This gave me 3400W for each cab and I
think this is where they are comfortable. I just need another amp to do
this on a regular basis. Not so much for SPL volume, but for the
headroom.
Check out the new Crown I-Tech amps. The I-Tech 8000 puts out 4000W per
channel @ 4 ohms. Just what the doctor ordered. =)
Another plus of the I-Tech is that you have not only a clip limiter, but
a RMS power limiter AND a peak voltage limiter. Properly set, those can
prevent the amp from clipping, the speaker coil from melting (over powered)
and the driver from over excurding (to much peak movement).

Mike Borkhuis
Audio Images Sound & Lighting, Inc
www.audioimagesonline.com
Blind Joni
2004-08-12 20:39:08 UTC
Permalink
Post by Mike
Check out the new Crown I-Tech amps. The I-Tech 8000 puts out 4000W per
Another plus of the I-Tech is that you have not only a clip limiter, but
a RMS power limiter AND a peak voltage limiter. Properly set, those can
prevent the amp from clipping, the speaker coil from melting (over powered)
and the driver from over excurding (to much peak movement).
Mike, any input on how they sound compared to say a QSC PL9.0 or other
Crowns..in real woprld apps?
Sub applications mostly.
John A. Chiara
SOS Recording Studio
Live Sound Inc.
Albany, NY
www.sosrecording.net
518-449-1637
Mike
2004-08-13 05:07:30 UTC
Permalink
Post by Blind Joni
Mike, any input on how they sound compared to say a QSC PL9.0
or other Crowns..in real woprld apps?
Sub applications mostly.
We had an I-Tech 4000 and 8000 in the shop for a demo. Didn't get a
chance to play with them too much or take them to a gig.

Mike Borkhuis
Audio Images Sound & Lighting, Inc
www.audioimagesonline.com
Dale C
2004-08-13 02:31:59 UTC
Permalink
Post by Mike
Check out the new Crown I-Tech amps. The I-Tech 8000 puts out 4000W per
Post by Mike
Mike Borkhuis
Audio Images Sound & Lighting, Inc
www.audioimagesonline.com
Do you have any idea what this unit will cost?


Dale
Mike
2004-08-13 05:06:25 UTC
Permalink
Post by Dale C
Post by Mike
Check out the new Crown I-Tech amps. The I-Tech 8000 puts out
Do you have any idea what this unit will cost?
Have to check the price sheet.

Mike Borkhuis
Audio Images Sound & Lighting, Inc
www.audioimagesonline.com
Douglas R. Allen
2004-08-13 23:03:41 UTC
Permalink
Post by Dale C
I have a pair of 218 cabs. They are Peavey DTH with the higher quality BW
speakers in them. These are rated at 2000W rms and 4000W program each cab. I
think I am seriously underpowering them with 1/2 of a QSC 3402 (1100W) on
each of them.
I did try to use the QSC in bridge mode for a night on one cab, and another
QSC on the other. This gave me 3400W for each cab and I think this is where
they are comfortable. I just need another amp to do this on a regular basis.
Not so much for SPL volume, but for the headroom.
Dale
I own 4 dth 218b's . Each speaker in the box is rated at 500rms,
1000 program with 2000 peak.
The two in the box gives you 1000 watts rms , 2000 program, with 4000 watts
peak for the box. It says so on the back input plate.
3400 watts is asking allot from these guys. I use a rmx1850 bridged per box
for 1800 watts rms and they work well. I have used my gps3500's bridged per
box for 3500 watts at 4 ohms and I felt power compression kicked in at that
level. The voice coils got to hot and output dropped. Headroom is nice but
continue to use common sense as it seems you do.

Kindest regards.
Doug

Mike
2004-08-12 04:11:48 UTC
Permalink
Post by Tom Hole
The best advise I have received through this whole
If you need more SPL, buy more speakers, not bigger amps.
I'd say buy more speakers AND amps. =)

AND, run your amps at a 4ohm per channel load, not 4 ohm bridged.

Mike Borkhuis
Audio Images Sound & Lighting, Inc
www.audioimagesonline.com
Mike
2004-08-12 04:08:35 UTC
Permalink
Post by Tom Hole
The cabs were fine, the 2450 was not. My fault, of course, as it
was showing a clip light and I pressed on anyway. I had the built
in limiters engaged and the amp has shut down on me twice.
Ah ha....
Post by Tom Hole
Figured 2 2450's would ease up on the amps. Just want to make
sure there is no failure mode and that means I need to be more
disciplined with the gain structure.
Sounds like you're not getting enough out of the subs in general. If
that's the case, you'd be best off doubling the whole rig, subs and amps.
That would provide you with the headroom you're looking for to stop clipping
tha amps.
Something else to look at would be your crossover and high pass filter
settings. Tuning those affects how much sound (the bandwidth) that the subs
are trying to reproduce. EQ settings also come into play...

Mike Borkhuis
Audio Images Sound & Lighting, Inc
www.audioimagesonline.com
Tom Hole
2004-08-12 12:43:11 UTC
Permalink
Post by Mike
Post by Tom Hole
The cabs were fine, the 2450 was not. My fault, of course, as it
was showing a clip light and I pressed on anyway. I had the built
in limiters engaged and the amp has shut down on me twice.
Ah ha....
Post by Tom Hole
Figured 2 2450's would ease up on the amps. Just want to make
sure there is no failure mode and that means I need to be more
disciplined with the gain structure.
Sounds like you're not getting enough out of the subs in general. If
that's the case, you'd be best off doubling the whole rig, subs and amps.
That would provide you with the headroom you're looking for to stop clipping
tha amps.
Yup, I think you are correct, sir. Until I can add a sub or two, I need to
use the system properly.
Post by Mike
Something else to look at would be your crossover and high pass filter
settings. Tuning those affects how much sound (the bandwidth) that the subs
are trying to reproduce. EQ settings also come into play...
Right now, the subs get 30-75Hz. I feed them through an aux, then a xover.
Now I'll just use the 4 band PEQ on the 01v96.

Low shelf - 30Hz
2 PEQ's
High shelf - 70-78Hz depending on the room

Tops are EF500P's crossed at 100Hz. Assymetric to account for the hot subs
(heavy metal band).

The 2 PEQ's will be nice to have. I tried a 31 band eq, but there just
aren't enough sliders between 30 and 80 Hz to make much of a difference.
Post by Mike
Mike Borkhuis
Audio Images Sound & Lighting, Inc
www.audioimagesonline.com
Tim Padrick
2004-08-12 20:38:10 UTC
Permalink
I think a 2450 per box sounds about right.

I think your hi-pass might be a bit low, however.

Even though the subs are cranked, are you sure you still don't have a dip
between the subs and tops?

Getting the tops properly delayed to the subs can make quite a difference in
how much sub you seem to have. Owing to the delay that's put on the subs by
the high pass and low pass filters, even with front-loaded subs the required
top-box delay can be substantial (with my system it's almost 13').

Make sure the subs are less than 1' or more than 8' from any boundary (wall,
floor) (Boundary Cancellation).

If possible, put the subs together (The Power Alley).

http://www.padrick.net/LiveSound/SubwooferInfo.htm
Post by Tom Hole
Post by Mike
Post by Tom Hole
The cabs were fine, the 2450 was not. My fault, of course, as it
was showing a clip light and I pressed on anyway. I had the built
in limiters engaged and the amp has shut down on me twice.
Ah ha....
Post by Tom Hole
Figured 2 2450's would ease up on the amps. Just want to make
sure there is no failure mode and that means I need to be more
disciplined with the gain structure.
Sounds like you're not getting enough out of the subs in general.
If
Post by Tom Hole
Post by Mike
that's the case, you'd be best off doubling the whole rig, subs and amps.
That would provide you with the headroom you're looking for to stop
clipping
Post by Mike
tha amps.
Yup, I think you are correct, sir. Until I can add a sub or two, I need to
use the system properly.
Post by Mike
Something else to look at would be your crossover and high pass filter
settings. Tuning those affects how much sound (the bandwidth) that the
subs
Post by Mike
are trying to reproduce. EQ settings also come into play...
Right now, the subs get 30-75Hz. I feed them through an aux, then a xover.
Now I'll just use the 4 band PEQ on the 01v96.
Low shelf - 30Hz
2 PEQ's
High shelf - 70-78Hz depending on the room
Tops are EF500P's crossed at 100Hz. Assymetric to account for the hot subs
(heavy metal band).
The 2 PEQ's will be nice to have. I tried a 31 band eq, but there just
aren't enough sliders between 30 and 80 Hz to make much of a difference.
Post by Mike
Mike Borkhuis
Audio Images Sound & Lighting, Inc
www.audioimagesonline.com
Pooh Bear
2004-08-11 17:42:42 UTC
Permalink
Post by Tom Hole
I have 2 Yorkville LS1208's. Yorkville lists them as 1200W program. As you
am putting a 2450 on one and a Behringer 2500 on the other which will be
1500W each. Over on the Harmony-Central board, they say that's nuts,
waaaayyy too much power. Whadyall think? I plan to use the limiter in the
01v96 to keep the amps out of clipping. I DO NOT want to blow the 1208's.
They are doing great with whatever the single 2450 was providing before, so
I would like to keep it at that.
2 x 1500W gives exactly a 0.97 decibel increase over 2 x 1200W.

Barely audible. Why bother - especially when you're increasing the potential for
damage.

The limiters in the amplifers will stop the clipping anyway too. I assume you
have them engaged.


Graham
Rupert
2004-08-12 00:12:37 UTC
Permalink
Post by Tom Hole
I have 2 Yorkville LS1208's. Yorkville lists them as 1200W program. As you
am putting a 2450 on one and a Behringer 2500 on the other which will be
1500W each. Over on the Harmony-Central board, they say that's nuts,
waaaayyy too much power. Whadyall think? I plan to use the limiter in the
01v96 to keep the amps out of clipping. I DO NOT want to blow the 1208's.
They are doing great with whatever the single 2450 was providing before, so
I would like to keep it at that.
Thanks in advacne,
Tom
A few hundred watts over the program rating should not be a problem.
Unless the signal source has an extremely low crest factor (less then
6dB-which no modern music is), you won't exceed the RMS rating of the
drivers. And, a few hundred more unclipped watts is not going to cause
over excursion of the drivers. If anything, you gain a slight amount
of clipping headroom. Remember, most speaker program ratings are a
guildline. A little under or a little over is usually a non-issue.
Since different amps behave differently with the same load, you can
never be sure exactly how much power an amp gives a speaker anyway.
Just keep the match up within common sense (hopefully) reasonable
limits.

Rupert
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