Originally Posted by Pete_Hsu
I recommend picking up a Radio Shack SPL meter so that you can use the test tone CD to take measurements at your listening position from 16-200Hz.
Regarding the Auto-On functionality, very very few customers have any issues with it kicking on when the subwoofer volume knob is relatively low, but a simple and easy fix is to set the On/Off/Auto switch to 'On'.
Where are you placing the subwoofer in room, and what are the room dimensions (including openings to other areas)? What settings are you using on the back of the subwoofer amplifier, and what are the speaker/subwoofer settings on the receiver set at?
You may want to make use of some Auto-EQ to smooth your in-room response. The Sunfire has this functionality already included I believe.
We've tried (4) four locations for the sub. Rear Left and Rear Right and Front Left and even Front Left away from the corner. Sub is still the same. Used all the same cables as the Sunfire. Swap the HSU out and put the Sunfire in and the issue is gone. So it's not room placement as the Sunfire in same positions sounds fine. Pushing the Sunfire and the ULS-15 around the room is a lot of work. My wife is screaming at me about the carpeting so I'm being careful.
As for Room dimentions it's 14 D x 27 W x 9 H. I don't think it's the room size that distorts the sound as the Sunfire has no issue with it.
With the Sunfire I feel as if the Drum set is in the room. I've worked for RCA, SONY, ARISTA, BMG, JIVE, WEA and others and I've been blessed to sit in on many studio recordings I know what drums sound like. I can get the effect of snap, speed, clarity and punch with the Sunfire with a kick-drum. Now I work most in TV and have great reference points for what real drums sound like at the lower registers. Granted I'm an Executive not a Tech but I do know quite well what the real thing sounds like.
I've tried the following:
1. Trim settings all the way from 15 to 50 in ten steps
2. I've tried the volume... at too low there is no power when I get to pressure levels near the Sunfire I get boomy and muddy. The music is distorted.
3. I've set the phase in both directions with some very slight bump up but no effect on trying to get the boomy muddy effect out
4. I've tried having the Denon control everything by setting up the Room EQ as this is a function of the 4308IC
5. I've tried taking the EQ out from the Denon and using the roll off, and trim, and volume on the ULS but I still can get the puch without the boomy muddy effect. Again if I take the ULS out of line the sound stage is pure and clean.
6. I've tried rolling off the 6 Canton CT 1000's at 40 - 60 and 80
7. I've tried 4 room positions and even swaped out the HSU ULS-15 with the Sunfire and the Sunfire sounds clear, crisp and sharp and fast. I can't get that same setting on the ULS-15
8. I've tried every combination on the Denon from "Pure Direct" to "EQ" to "Stereo" with 7.1 Material, 24/96, FLAC, SACD, and some very high end mastered recordings. They all lack the "speed" "clarity" and "being there" feeling on the lower bass side.
9. I thought something could be wrong with my system so I did a hard re-boot for the ULS-15 and did a total new EQ of the Room wiping out all my setting. I did the EQ from 8 locations near the sweet spot in the room.
10. I've used the ULS with and without the feet
11. I tried using a splitter for left and right input as opposed the the single SUB out on the back of the Denon
12. I've tried wireless vs. wired and that's someplace I'm not ready to go. No help and wireless seems like the music is not in sync as well as wired.
13. I've hooked a Good Panasonic CD player directly to the ULS-15 that allows me to take the AMP and PRE-AMP out of the chain and control the volume / gain on each channel. Then I took an old Krell 2 channel AMP that's a great product and hooked up two of the Canton CT-1000's. With the Sunfire the sound is amazing in stereo. With the ULS-15 even in this pure direct mode I get a clear muddy boomy sound.
One thing I must say is that the EQ in the Sunfire is dedicated to the SUB. Two, the Sunfire cost twice as much.
The issue with the Sunfire is that I've had to repair it a few times. It sounds fantastic BUT I'm tired of getting it fixed.
The Auto on works on the Sunfire by the way. The Sunfire runs hot, the ULS-15 does not. I'm sure 2700 watts causes the Sunfire to run hot.
I have a friend coming over who is a recoring engineer from the RCA Recording Studio in New York City on Sunday. I used to sit in on his recordings at 1133. He's offered to help this Sunday. Perhaps an engineer will be able to figure this out.
I feel like I've tried just about everything and need an expert at this point.