subwoofer shuts off

JKroon -- Mon, 05/29/2006 - 11:04

I'm having trouble setting up a new surround sound system. I bought an NAD T763 receiver, 2 pairs of Epos ELS3s, ELS center channel and ELS sub. My source is a Toshiba DVD player. The DVD player is connected to the receiver via a coaxial digital cable. My problem is, whenever there is a loud bass passage in a movie, for example the first scene in Star Wars Episode II where the star cruiser flys by, the subwoofer makes a loud pop and shuts off. The only way I can figure out to get around this problem is to turn the subwoofer's volume down, but I had to turn it down to the point where the subwoofer is barely audible. I e-mailed Epos about my problem and they told me to turn the sub channel down on the receiver because the ELS sub is designed for a 2 Volt preamp output and they said some a/v receivers have preamp outputs as high as 10 volts. I have the sub channel on the receiver turned to -10. The volume control on the sub is turned up about 1/4 of the way, and the sub doesn't shut off anymore. However, for the bass to sound balanced with the rest of the system, I need to turn the subwoofer's volume control up half way. This works fine for music, but the sub seems like it can't handle movies. Am I doing something wrong?

Tom Martin -- Thu, 06/01/2006 - 17:25

How big is your room?

CEO and Editorial Director, Nextscreen LLC

JKroon -- Mon, 06/05/2006 - 09:52

20 ft. by 30 ft.

Tom Martin -- Mon, 06/05/2006 - 16:20

That's big. I would suggest that maybe one sub isn't enough for high level low frequencies in such a room. How big is the driver in your sub?

Tom Martin -- Mon, 06/05/2006 - 16:24

I would also try adjusting the low frequency cutoff (I'm not sure what it is called on the Epos sub) to a higher frequency. The Epos will go very low, but the lower you go, and the larger your room, the more the driver has to move, and, well, at some point it can't move any farther.

JKroon -- Mon, 06/05/2006 - 16:48

You may be right about one sub not being enough. The sub has two crossovers, one for the high frequency cutoff and one for the low frequency cutoff. I have the high set at 70 Hz (I used a test tone disc and SPL meter) and the low set at 20 Hz. Before I set the cutoff frequencies the sub had output down to 10 Hz (only 55 dB, 88 dB from 20 Hz to 70 Hz +/- 5dB. I tested it in 1 hz increments with the receiver volume set at my normal listening level)

Tom Martin -- Mon, 06/05/2006 - 18:51

My room is 26 x 19 and I use 2 Velodyne DD15s. That means, assuming similar excursion capability vs the Epos, that I have 5X the air movement capability in 85% of the volume. And I will say the Velodyne's work hard in my room and I don't listen at terribly high levels. I also use at 24 hz low frequency cutoff. These things are hard to compare, but raising the lf cutoff is a worthy experiment until you can add a woofer.

Chris Martens -- Tue, 06/06/2006 - 17:15

Let me second T. Martin's commentary on the Epos subs vis-a-vis your room size.

I did the original AVguide/TPV/TAS review of the Epos surround system, and I thought the Epos ELS sub offered considerably more truly low bass output than many of the more mid-bass-oriented subs I had heard. But one corollary of this is that you can easily reach the ELS Sub's output limits in a large or even a mid-sized room (though I would consider yours to be a very large room).

The ideal solution would be to add more ELS subs, if your budget permits.

However, a temporary workaround is to use a higher low frequency roll-off setting when listening to films. This will still give you a relatively satisfying mid-bass "Ker-woomph" on low frequency effects, but without letting the woofer bottom out quite so easily.

Best,

Chris Martens
Audio Editor, The Perfect Vision
Senior Writer, The Absolute Sound

Chris Martens
Editor, Avguide.com/Playback/The Perfect Vision

JKroon -- Wed, 06/07/2006 - 14:29

Sounds like a plan. Thanks guys!

JKroon -- Sat, 06/17/2006 - 16:12

I bought the second subwoofer, adjusted both subs, problem solved!