Yorkville Ls801p (B) measurements.

[Douglas R. Allen]

I have some Yorkville LS801pb subs now. Some say these subs are boomy and need eq. I took the time to measure them and found they are flat and within spec. If you use the Loud/Deep switch in the Loud spot they are flat. If you put it at 12 o'clock it has a 3 db boost at 50 hz and all the way to Deep it has a 6 db boost at 50hz. This could be what some call boomy.
I'll post my measurements should anyone use these subs or wanted to see how they look when using the Loud/Deep switch. I did all measurements with a 6db down at 120hz point. Later in use I set the knob to 90.

First picture is my measurement setup.
2nd is the back settings I started with.
3rd is the reading I got.

Douglas R. Allen

 

[Douglas R. Allen]

Re: Yorkville Ls801p (B) measurements.

Next I turned the Shape knob to Deep.
You'll see a big boost at 50hz. 1st picture. This gave a 6db down point at 38hz instead of 45hz. But the uneven response may be what some say is boomy?
Wanting the extension in response but not the boost I add a filter at 50hz. This gave a flat response and still a 6db down at 38hz but no 50hz boost
On my 01v96 I added a filter with a Q of 6.3 with a 5.5 db cut at 50 hz to give a 38hz 6db down point yet a flat response to the 6db down point of 120hz high cut.

Douglas R. Allen

 

[Rob Timmerman]

Re: Yorkville Ls801p (B) measurements.

I note that the internal crossover in this sub is a 12db/octave unit, not a steeper 18 or 24 db/octave unit that it may be assumed to be. The shallower rolloff could contribute to the "boomy" characteristics if the system tech is expecting a steeper rolloff, as there will be more energy around and above the crossover region than might be expected. This is especially the case if these subs are being combined with tops that have a steep rolloff and the crossover point is set symmetrically.

 

[Douglas R. Allen]

Re: Yorkville Ls801p (B) measurements.

I note that the internal crossover in this sub is a 12db/octave unit, not a steeper 18 or 24 db/octave unit that it may be assumed to be. The shallower rolloff could contribute to the "boomy" characteristics if the system tech is expecting a steeper rolloff, as there will be more energy around and above the crossover region than might be expected. This is especially the case if these subs are being combined with tops that have a steep rolloff and the crossover point is set symmetrically.

Could be. The Low cut looks like a standard 24db cut but the High Cut looks to be some kind of stagger pole design. Starts off with a single 12db then another one seems to comes in higher up for a steeper slope at the end. Not sure why they did this. I do know the EF500p tops I use combine with them fine and have what looks like a 100hz 24db cut in them. Next time I have a chance to measure them I'll spin the High Cut knob and see if it stays the same in all frequency settings.

Douglas R. Allen