2 x Ultimax 18's Unrealistic expectations or something wrong?

[joshp214]

^^^Readings

Here's the subwoofer setup.

2 x Dayton Ultimax 18's in PE knockdown sealed cabinets
Behringer Inuke6000dsp
Yamaha RX-V765
To start, I understand the concepts behind ported vs sealed boxes and whatnot. I also understand that it takes lots of displacement with sealed boxes to achieve a decent level of spl when it comes to sub 30hz fq.

My question however is about the sound quality of my setup at these lower frequencies. Overall, the subs are loud, and sound "pretty good" above 30 hz, but when lower frequencies come in during movies, or simply playing bass tracks the subs just fall on their face, and almost have an "unlinear" sound, i.e. floppy, or just down right dirty sounding.

Am I being Unrealistic with my expectations of this setup? My 2 10's in the car actually sound nice and clean when playing the same material (also understand comparing these are like apples and oranges).

I do have a UMIK-1, and looking at the graphs tell me the same thing my ears are hearing. Severe roll off after 30 hz, and under 20 hz it almost looks like a sin wave lol....just looks dirty. Maybe I have something wrong in the dsp on the Behringer, or maybe I am being unrealistic. I do not have access to the graphs at the time of this posting, but can anybody give me a little direction, or a point of view? Thanks!

[killa]

Re: 2 x Ultimax 18's Unrealistic expectations or something wrong?

Can you post measurements? Also where are the located in the room? Room modes have caused many great subs to sound like poop.

[joshp214]

Re: 2 x Ultimax 18's Unrealistic expectations or something wrong?

Like my original post said, I don't have access to the graphs at this time, but I can post them at a later time hopefully. I know that would help to be able to see them.

[killa]

Re: 2 x Ultimax 18's Unrealistic expectations or something wrong?

Like my original post said, I don't have access to the graphs at this time, but I can post them at a later time hopefully. I know that would help to be able to see them.

Thats what I get for skimming :o also I added to previous post

[Pete Basel]

Re: 2 x Ultimax 18's Unrealistic expectations or something wrong?

Do you have a scope to look at the waveform at the speakers or input to the power amp,
is something clipping upstream?

[joshp214]

Re: 2 x Ultimax 18's Unrealistic expectations or something wrong?

Subs are located in front of the room, one in a corner, other is on the opposite side of the TV and both are facing to the right (toward the corner). The room is very big, 37l x 19w x 11h, and opens to the dining area/kitchen. It definitely has areas where the sound dies, but the problem I am referring to is evident anywhere in the room, whether right beside the sub (either one), or out into the room.

[joshp214]

Re: 2 x Ultimax 18's Unrealistic expectations or something wrong?

Do you have a scope to look at the waveform at the speakers or input to the power amp,
is something clipping upstream?

No I dont, but that could be a possibility. I do need to mention there is a 60 hz hum issue that I need to fix as well.

[Jeff B.]

Re: 2 x Ultimax 18's Unrealistic expectations or something wrong?

Are you using anything to increase the input voltage from your receiver to the iNuke? Receivers by themselves often don't have enough output to drive prosound amps.

[joshp214]

Re: 2 x Ultimax 18's Unrealistic expectations or something wrong?

No, it's plenty loud, and the amp can drive the speakers beyond full excursion. Low output isn't an issue

[kevintomb]

Re: 2 x Ultimax 18's Unrealistic expectations or something wrong?

How many cubic feet are the enclosures?

[killa]

Re: 2 x Ultimax 18's Unrealistic expectations or something wrong?

This may be stupid but are you sure you wired the subs with the same polarity? A rapid drop after 30hz could be caused by cancellations of some sort. Could also be a highpass filter in the amp but you make it seem like the woofers are moving a lot but not making much sound.

Also as Pete stated you could be clipping the input. I remember another thread recently where someone had different input voltage selections on their amp and they were clipping because it was set to the wrong input voltage.

[joshp214]

Re: 2 x Ultimax 18's Unrealistic expectations or something wrong?

How many cubic feet are the enclosures?

They are the Parts Express 4 cu ft knockdown sealed boxes

[joshp214]

Re: 2 x Ultimax 18's Unrealistic expectations or something wrong?

This may be stupid but are you sure you wired the subs with the same polarity? A rapid drop after 30hz could be caused by cancellations of some sort. Could also be a highpass filter in the amp but you make it seem like the woofers are moving a lot but not making much sound.

Also as Pete stated you could be clipping the input. I remember another thread recently where someone had different input voltage selections on their amp and they were clipping because it was set to the wrong input voltage.

Yep, woofers are moving alot below 30 hz, but sound like poop. Already checked polarity, everything is good there. It could very well be something in the crossover, or could be some clipped signal somewhere.

I know thereally are some folks that have this exact woofer/amp setup, and I'm hoping somebody will chime in to say I'm crazy or that they have the same issue.....

[killa]

Re: 2 x Ultimax 18's Unrealistic expectations or something wrong?

Are you using anything to increase the input voltage from your receiver to the iNuke? Receivers by themselves often don't have enough output to drive prosound amps.

From what I have read the inuke works just fine with HTRs without a voltage box thingy (forgot what they call them) but I think this amp might have a select-able input voltage.

[killa]

Re: 2 x Ultimax 18's Unrealistic expectations or something wrong?

Yep, woofers are moving alot below 30 hz, but sound like poop.

It is odd that the woofers move a lot below 30hz even though you measured a huge dropoff after 30 hz To me that screams cancellation of some sort.