I recently setup my Denon reciver and Velodyne DLS 3750R sub and am having a bit of an issue. For starters I performed that auto speaker setup thru the Denon which stated to turn the Crossover on the sub to "direct" and the volume to the middle (so 50 out of 100). Anyway, auto setup put the chaennl level for the sub at -9db, and the sub would boom when I turned the reciver on and boom louder when I turned it off. So, I lowered the volume on the sub to 35 or of 100 and auto setup put the channel level at -3 db. The boom is lower but still present. I guess I can continue to lower the sub volume until the auto setup reads 0 db for a cahnnel level but my concern is am I going to just be producing less bass the more I lower it.
Are you confusing the crossover setting with the level set? You refer to both as "out of 100". Normally the crossover point on the sub is set as high as possible if you are allowing the receiver/processor to do the actual low frequncy effects roll in/out.
I asssume the problem is with the "boom" at power up and down and not that the sub "booms" when playing music. This is a distinct difference that I can't follow in your post. If the problem is at power up and down only, you probably have a fault in a mute circuit. It can be in either the receiver or the sub. Which is the newer of the two?
Sorry, the out of 100 figures are the volume I set on the sub itself. At first trying 50 out of 100 (based on the receivers instructions for auto setup)and then lowering it to 35 out of 100. The channel level I spoke about was the level that the receiver gave the sub after the setup, -9db when I set the sub at 50 and -3db at 35.
You are right, I did set the crossover as high as possible (called Direct on the sub) because that's what the receivers auto setup function said to do.
The problem is only at the power on and off. Both the receiver and sub are brand new, less than two weeks old.
Don't bother with setting loudspeakers to small it defeats the whole purpose they should be set to large. The Sub bass should when in Dolby stereo digital 5.1 mode play the LFE.1 as and when it's in the film mix and it should only accompany or support the sequence not overwhelm it where it would stick out like a sore thumb.
If I was there I could solve this matter in less than an hour.
Now if your fronts are lacking slam kick and depth within a small degree than I should seriously consider getting matching fronts or better still pop into a local cinema one that holds THX status and ask a few questions to the projectionist get him to show you around what is behind the screen and you'll soon twig on.
I assume Nuck is trying to determine whether the receiver or the sub is at fault here. If you can follow his directions, you might find one or the other has a problem, though typically most active subs don't have an actual on/off switch. Unplugging the sub from the AC outlet is quite often the only way to power down an active subwoofer and quite a few subs thump when plugged into the AC outlet. So, do what you can but I would simply call the shop where you made the purchase and ask for some after the sale assistance. Or, haul one or both units back down there and ask them to demonstrate how to solve this problem. That's what brick and mortar shops are all about, customer service.
ok, so as long as i followed the Nuck correctly i played some music with the sub off. Mine does have an on/off switch. I then lowered the volume on the receiver to nothing, then powered on the sub and then slowly turned up the volume on the receiver.... no thump was produced.
Now for your last post - no I don't turn the volume all the way down prior to powering the unit on or off. Seems strange that i would have to do that. That being said though... with the reciver volume all the way down I still get the boom from the sub when i power on and off.
It seems to me that for what ever reason the reciever is sending out a loud signal to the sub when i power on and off.
If the seller admits there is a problem but cannot solve the problem, they should offer a replacement after only two weeks of ownership. Asking them to do so will probably speed up their ability to determine which unit is at fault.
I worked thru a few things with them today but it still didn't work. They gave me a replacement sub but that had to effect. Next will be the receiver, hopefully that does it.
Your problem was in the mute circuit for the sub which is part of the receiver architecture. All Denon receivers use two mute transistors to keep transients out of all the preouts during turn on and turn off as well as when changing functions. These are special transistors typically 2SC2238's or 2SD1915's (Your's was using a newer surface mount version of this type of transistor) and are prone to becoming defective especially in the subwoofer circuits where you are connecting a seperate active device to the receiver. Static electricity can damage the transistors and what you are hearing is -11 volts being pumped directly to the sub. These transistor bases are switched from +5 volts (mute on) to -11 volts (mute off). When damaged they leak this voltage onto the emitter connected to the signal line and you hear it as a loud thump. Also, contrary to an earlier post, if you set your front speakers for "Large" then virtually all of the LFE content is steered to them and leaves the subwoofer out of the picture regardless of how you set it up in the menu. Most manufactures follow this rule, i.e. Sony, Yamaha, Denon, etc. I don't have all the answers but I've be repairing/modifying consumer audio equipment for 40 years and can answer most technical questions regarding problems consumers experience and can't find answers to. Don't ask me to critique this stuff though, I just fix it, modify it, or re-engineer it to work like it should.