new subwoofer king?

[Jay481985]

I don't have it yet, looking for a person to make me one. It will be a 24 inch cube. triple 18 in prs

Contact Kyle, he is back with Thilo and they are supposed to be back soon.

[DrWho]

Can you post a plot where the scale is from 10Hz to 200Hz and from 75dB to 105dB? It will make your frequency response look nasty, but will be more reprentative of what's going on.

But even then, the shape of the frequency response curve doesn't tell you much about the perceived sound quality. I've got a single 12" driver with a 250W plate amp that measures quite similar to your plot, but I can guarantee that they won't sound the same. Although, I might argue that in the same room that they will sound more similar than dissimilar until the SPL gets high enough to cause the weaker system to distort. Even with the most insane subwoofage, the room dominates much of the sound.

Also, you can move the mic a few feet or even a few inches and the response can change quite dramatically.

[robertcharles]

These are the first graphs from my new REW setup. I am working the bugs out, but this is what you asked for? Yes/No?

[DrWho]

Yea, that's unsmoothed right?

Is there any dimension in your
listening space that is about 75 feet long? The two dips right next to
each other around 16Hz could be your tuning not keeping aligned with
your active drivers.

Do you have any stuffing in your cabinets?

You
might need to push the tuning a bit higher to get rid of that dip. The
dip itself isn't so bad, but I have a feeling your actives could be
unloading early which will result in excessive cone motion for the same
SPL....not that excursion is particularly a problem in your setup, but
fixing it should lower the distortion.

Of course that's all
purely speculation at this point....an outdoor measurement would
probably be more informative (albeit a lot more work I'm sure). An impedance plot would be interesting too.

Are
your subs not positioned in corners? And these are sub only plots right?

[robertcharles]

Yep. Unsmoothed.

The cabinets are along a side wall. When measuring, I measured at listening position. I will measure ground plane, but this will only be on one baffleor the other. I could also measure on the side of cab with no direct driver passive radiation.

Subs only.

I will set the REW up and run a few suggestions if you don't mind. I really do not get any room gain. The graph looks very much like the model that I used to build the cabs.

They are pretty much stuffed. The tuning is at 14.2 Hz.

[robertcharles]

My room is 20 wide, 30 long, and 8 feet high.

I will say, I do not really ever get excessive cone movement. I get tremendous SPL levels and the cones are always moving well within xmax. I have seen the LMS drivers going to max in a demo, and I am in no way even coming close to xmax-I do not know if I would even want to approach those levels.

[robertcharles]

The new graph is going through a crown itech 8000. The old graph a few months back was from an old alesis. I think the crown has a built in rolloff at 8 Hz.

I am going to use a different amp to do measures to compare.

[DrWho]

The point isn't that you run outta xmax, but that excessive cone motion for the same SPL creates distortion.

I don't think I'd worry too much about the performance below 8Hz or even 15Hz for that matter.

[robertcharles]

I follow you on that. My point is that I have seen an LMS running all out and it was quite impressive. I have not even come to 2/w3 of what I saw the LMS do in the demo and I have way more than enough from the setup as is. I am trying to get set for some AB measures to see what is going on. I might need a little input.

Thanks,

Robert