I recently purchased a HSU Research VTF2-MK2 from a friend, it's about a year and a half old, and from what I could hear, sounded good on his system. When I first hooked it up to my receiver (Yamaha) using the sub out, I wasn't getting any sound from the sub. When I put it on the test tone, and turned the level in the receiver, and the volume on the sub all the way to max, I heard a very very light rumbling coming from the sub. When I watched movies, or music, no sound that I could hear came from the sub.
While I had it on the test tone, I turned the base on the reciever to maximum, turned the volume up to -10db, and suddenly the sub was making a very loud rumbling. Now when I have it on a movie, if I turn the volume up to -10db or louder, the sub makes sound, but it is a very loud, almost burbling sound when it fires, it only does it when loud action is taking place on the movie, but the sound it produces is not what I would call good, it doesn't match well with the soundtrack coming from the main speakers, just a loud burbling base sound.
Also there doesn't seem to be any mid ground to the volume level coming from the sub, it's either way loud, or so soft you can't hear it. I messed with the volume on the reciever with the volume on the sub volume maxed, and if I have it at -15db, no sound can be heard from the sub, but if I up it to -10db, the sub comes on very loudly.
Any ideas on what would cause this to happen? I've ruled out the receiver as the cause (tried two different receivers, same model, same result).
First: TURN THE VOLUME DOWN. If you move the right control at full volume, the sub will launch and you will damage something... Read the Manual...... Try to understand the controls. Did your friend use the Speaker level inputs or the low level inputs (RCA)?? If I remember correctly, a single RCA should be connected to the LEFT input.
Don't forget to power down when making/breaking these connections.
Looking at the back of my VTF-2, the only other thing I can think of is that you have the crossover switched in or out when it should be the other way.
I understand the volume up that high could damage something, but I was desperate to get at least some sound out of the sub.
I read the manual for both the receiver and sub, and I understand the controls.
He used the RCA input, exactly how I have it set up (same cable even). You are correct, it is a single RCA into the left input.
Thanks for the tip on powering down before making switches. Crossover isn't switched, I've tried both using the internal crossover in the sub, and the crossover in the receiver. I actually posed the same question to Hsu, and they think the Amplifier needs maintenance, and asked me to send it to them, so I think that will be my next step unless someone else has a suggestion.
I can think of 2 more things to try. 1. Try a different cable. It is possible that your cable is shorted....maybe somebody pulled it out by the wire without gripping the connector? 2. Turn sub vol ALL THE WAY DOWN and try plugging sub into any fixed level output. play anything and then SLOWLY turn the sub's vol.control UP> If you get something out, it ain't the sub, but the receiver.
ALSO, one other thing just occurred to me. Have you checked the receiver's menus? Is there a speaker size selector or sub setup submenu? If the sub isn't 'enabled' somehow, this could shut you down.