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Horns and distortion?
Posted: Sun Oct 27, 2013 6:25 pm
by Monomer
Had a hard time at the last show. I was told to not wall-load my t39's (they need it, being the slims) and to put them under the tops, to better phase-align the system. (I also delayed the tops...)
"The kickdrum is more important than output" "This isnt a dj rig"
So, I ended up with the normal subs under tops (not my call) to make them happy. Now, it didnt sound bad - but there was plenty of nulls in the room during the walkaround, and I did push the cabs harder than normal.
Is there a whitepaper anywhere that deals with the lack of IM/harmonic distortion in a horn-loaded system? I'm sure this is the problem, the normal distortion in ported boxs gives a much different sound, esp around the kickdrum.
Regardless, it did put the JBL srx rig that was normally in there to shame.
Re: Horns and distortion?
Posted: Sun Oct 27, 2013 7:45 pm
by Radian
Monomer wrote:Is there a whitepaper anywhere that deals with the lack of IM/harmonic distortion in a horn-loaded system?
Modulation Distortion in Loudspeakers - Paul Klipsch
Eight Cardinal Points in Loudspeakers for Sound Reproduction - Paul Klipsch
In addition, there also two excellent references cited by Klipsch in
Dope From Hope Vol.7 No.3 (1966) on Distortion.
Monomer wrote:I'm sure this is the problem, the normal distortion in ported boxs gives a much different sound, esp around the kickdrum.
It's more of a matter of getting the electronics set up well than fussing over the absolute location. Granted, the later
does facilitate the former.
*edit* Fixed a broken link
Re: Horns and distortion?
Posted: Sun Oct 27, 2013 8:38 pm
by Monomer
I knew you'd have the links I've been searching for.
I bet your bookmarks are all one needs to becomee an engineer, sans piece-o-paper.
Thanks!
Re: Horns and distortion?
Posted: Sun Oct 27, 2013 10:28 pm
by Radian
Monomer wrote:I bet your bookmarks are all one needs to becomee an engineer, sans piece-o-paper.
If only...
Monomer wrote:Thanks!
You're welcome.
Re: Horns and distortion?
Posted: Mon Oct 28, 2013 7:23 am
by Bill Fitzmaurice
Monomer wrote:Had a hard time at the last show. I was told to not wall-load my t39's (they need it, being the slims) and to put them under the tops, to better phase-align the system. (I also delayed the tops...)
"The kickdrum is more important than output" "This isnt a dj rig"
So, I ended up with the normal subs under tops (not my call) to make them happy.
If they were so damn smart how come they weren't using their own system?
The only thing one can be sure of by their comments is that they had no clue.
Re: Horns and distortion?
Posted: Mon Nov 04, 2013 7:56 pm
by Monomer
Bill Fitzmaurice wrote:Monomer wrote:Had a hard time at the last show. I was told to not wall-load my t39's (they need it, being the slims) and to put them under the tops, to better phase-align the system. (I also delayed the tops...)
"The kickdrum is more important than output" "This isnt a dj rig"
So, I ended up with the normal subs under tops (not my call) to make them happy.
If they were so damn smart how come they weren't using their own system?
The only thing one can be sure of by their comments is that they had no clue.
His system was in another room, and sounded great.
Even in the corner I did notice the kick a bit "lacking" normally on non-folded setups it's more prevelent. I know it's there, but I can never get the wall shaking kick that usually defines a "loud" system. Must be overpowered by that smooth, clean bass.
At higher spl, I notice a bit boxey-ness, As if the horn is choking. These are slims, When I set the crossover on the dsp it's usually at 80Hz for LP and 110hz for HP (24 db/oct L-R) on the tops. This gets rid of the boxeyness, but I believe I'm losing a bit of very important bandwidth. I've spent plenty of time trying different slopes and frequencys - still never completely happy.
Re: Horns and distortion?
Posted: Mon Nov 04, 2013 10:18 pm
by Bill Fitzmaurice
Monomer wrote:When I set the crossover on the dsp it's usually at 80Hz for LP and 110hz for HP (24 db/oct L-R) on the tops.
I wouldn't have that much spread between the filters with that steep of a slope. Maybe 90/100 at 24dB or 80/110 with 18dB. You need for the combined response of the tops and the subs to fill in the space in between their passbands, and it can't do that with the combination of too wide a space and too steep a slope.
Re: Horns and distortion?
Posted: Tue Nov 05, 2013 12:29 pm
by gdougherty
Linkwitz-Riley filters sum to flat when you match the frequencies. You are usually best off having no frequency spread since it will leave a little hole in response otherwise.
I also use eq to counter the rising slope of the cabinet and leave a little bump at 80hz. You're doing that a bit with the lower crossover point but your slope is probably steeper than you want there.
Re: Horns and distortion?
Posted: Tue Nov 05, 2013 2:12 pm
by Radian
gdougherty wrote:Linkwitz-Riley filters sum to flat when you match the frequencies.
Only when the two signals are flat.....typically only on paper.
In practice, the trick is to know what each individual cab response is doing when setup in application, then choosing an appropriate filter slope based on that which, in combination with the acoustic response, achieves the desired crossover.
For example:
A technician could put a LR24 high pass on the very tail end of a DR200 and still end up with an 18 dB/oct Chebyshev in the crossover region.
When one factors in how the response of each cab changes (subs and tops alike) due to the unique dispersion (hence placement) requirements of every application, setting up filters results in a juggling act where no one specific solution is applicable to every case. It is the crux of using active filter networks in a portable rig. The electronics will have to be tailored each and every time.
This is where getting the gear out or into to a large space and doing some low-level experimentation with RTA and documenting the findings really helps. That or purchasing an automatic, close-looped DSP to accomplish the same thing.
This is parameter-driven (or parametric) setup technique and is what separates an "okay" sounding system from a "spectacular" sounding system.
Re: Horns and distortion?
Posted: Tue Nov 05, 2013 5:55 pm
by Monomer
Bill Fitzmaurice wrote:Monomer wrote:When I set the crossover on the dsp it's usually at 80Hz for LP and 110hz for HP (24 db/oct L-R) on the tops.
I wouldn't have that much spread between the filters with that steep of a slope. Maybe 90/100 at 24dB or 80/110 with 18dB. You need for the combined response of the tops and the subs to fill in the space in between their passbands, and it can't do that with the combination of too wide a space and too steep a slope.
The slims seems REALLY sensitive in that range, and crossing that high simply doesn't sound good. I swear it seems as if I'm trying to push to much air outta such a small horn. Sounds....boxy, and not very musical.
Perhaps is the lacking low end, which usually isn't a problem when they're properly placed in the room.
Re: Horns and distortion?
Posted: Tue Nov 05, 2013 6:28 pm
by Bill Fitzmaurice
Monomer wrote:
Perhaps is the lacking low end, which usually isn't a problem when they're properly placed in the room.
Look at the SPL charts. If you're not wall loading them the low end won't keep up with the high end unless you've got eight of them, or you tame the upper end with EQ.
Re: Horns and distortion?
Posted: Wed Nov 06, 2013 8:49 am
by gdougherty
Radian wrote:gdougherty wrote:Linkwitz-Riley filters sum to flat when you match the frequencies.
Only when the two signals are flat.....typically only on paper.
In practice, the trick is to know what each individual cab response is doing when setup in application, then choosing an appropriate filter slope based on that which, in combination with the acoustic response, achieves the desired crossover.
For example:
A technician could put a LR24 high pass on the very tail end of a DR200 and still end up with an 18 dB/oct Chebyshev in the crossover region. :noob:
When one factors in how the response of each cab changes (subs and tops alike) due to the unique dispersion (hence placement) requirements of every application, setting up filters results in a juggling act where no one specific solution is applicable to every case. It is the crux of using active filter networks in a portable rig. The electronics will have to be tailored each and every time.
This is where getting the gear out or into to a large space and doing some low-level experimentation with RTA and documenting the findings really helps. That or purchasing an automatic, close-looped DSP to accomplish the same thing.
This is parameter-driven (or parametric) setup technique and is what separates an "okay" sounding system from a "spectacular" sounding system.
General practice I learned is eq the responses flat as much possible then apply the crossover. Certainly if you just left the rising response of the T39 in place, that would contribute to a bump in the crossover region like my response implied.
Re: Horns and distortion?
Posted: Wed Nov 20, 2013 10:06 pm
by Monomer
Bill Fitzmaurice wrote:Monomer wrote:
Perhaps is the lacking low end, which usually isn't a problem when they're properly placed in the room.
Look at the SPL charts. If you're not wall loading them the low end won't keep up with the high end unless you've got eight of them, or you tame the upper end with EQ.
Thats exactly what i'm doing with the crossover.
Itstead of pulling a bunch out with graphic eq, isnt one filter set a little lower a better solution?
Re: Horns and distortion?
Posted: Thu Nov 21, 2013 1:55 pm
by sine143
I usually compensate using 1 of 2 methods
a hishelf set around 110hz pulling down around 4 db (with a slight paremetic boost, Q, 2.0 around 60ish, about 1 to 2 db) with a 24 db/oct LR filter at 95hz
I just set a L/R filter at around 80 to 85hz).
this is for a stack of 4 t48s. when using 6 t48s, I use method 1 but loosen the hishelf a bit (to around 2.5db). Generally I use method one for things like house/techno (so you can still get the 100 to 200hz chest thump from the kick), and method 2 for DEEP dubstep (where the brunt of the track is centered between 35 and 50).