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View Full Version : Subwoofer calibration help, please!



curtis
06-04-2004, 07:51 AM
So the sub is calibrated to 85dB with the rest of the speakers? Did you test tones and calibrate the whole system at the same time? What is the receive set at?

Using test tones from the receiver or test disc, you play the tone through each individual channel and adjust the channel trim to the that each channel matchs 85dB...including the sub channel.

-curtis

Big_Nate
06-04-2004, 11:13 AM
I was using VE's test tones, setting each speaker to 75db but setting the sub a little higher at 85db. I guess what I'm not understanding is, what do I set the volume knob on the sub to when doing this? Do I leave the reciever sub level at 0 and only adjust the volume knob on the sub to reach 85db, or do I set the volume knob on the sub really low and the up the reciever level on the sub to achieve the needed db level?

curtis
06-04-2004, 12:19 PM
and it is bottoming out? Do you have the EQ switch on the sub set properly with and without the port plug?

Either way of adjusting should be fine. but generally you would want to keep the receiver setting close to 0.

-curtis

Lou-the-dog
06-05-2004, 02:12 AM
It seems that you prefer your sub settings pretty hot in relation to the rest of your speakers. If you are using a Rat Shack meter, due to low frequency insensitivity, your sub is really set somewhere around 90db... not 85db as the meter indicates. If you like loud listening levels then it is possible that you've pushed your sub to the limit. As Curtis suggested, if you have the EQ switch set to "one port open" and you don't have your port plug in then you could have bottoming and possibly push the unit to damage.

Randy

Big_Nate
06-06-2004, 08:38 AM
Thanks for the help guys, I'm understanding more now! Ok, the "port" switch is set to "1 port open", which I have, the other is plugged tight. I made some adjustments last night and ended up putting the volume knob on the sub a little past a quarter up (say, 15-17%?) and using the test signals put the reciever level up to +3. I put in Episode II and queued up the scene where Jango Fett is dropping those charges that explode various asteroids, this is the same scene in which I heard the sub bottom out on before. I turned up the volume on the reciever to -15db off the 75db ref level of 0 and go nice thundering couch-shaking bass with no bottoming out at all. I think before I could have had the sub's volume turned up too high? I'm still not sure what caused the bottoming out to happen, but it seems ok now.

With the VTF-2, should I be able to, in theory, calibrate it at 75db (maybe a little lower, due to the insensitivity of the SPL meter that Lou mentioned) and then run it at 0 or ref 75db level on my reciever? I'm thinking how I have it now, with the volume on the sub at a quarter way up and +3 on the sub level in the reciever that putting it much past where I had it at -15 would bottom it out or damage it.

Lou-the-dog
06-06-2004, 02:02 PM
I think you're getting it dialed in Nate. For movies, I prefer a setting on the hot side myself...there's nothing like watching the picture frames jump around on the walls. One needs to keep in mind that movies are all mixed differently and some have some huge LFE peaks mixed in. This is where you can get into trouble reaching the excursion limits of your sub...running your sub settings extremely hot AND listening at high volume levels. Set your sub levels where YOU like to listen but try to stay a tad short of the bottoming level. If eventually you find you NEED to dislodge even more plaster from your walls then add an additional VTF-2 or opt for a VTF-3.

On another note, have you optimized your sub placement? Usually moving the sub closer to a corner or wall will maximize your subs output. Also a near-listening position placement might be useful. A different placement might allow you to get the effect you desire but allow you to run your sub at a considerably lower setting.

Randy

Big_Nate
06-07-2004, 12:18 AM
Honestly, I haven't worked much on placement, mainly because of the wife factor. As long as it stays on the other end of the couch outta sight it's fine hehe. I do have the open port facing a wall, and the sub itself is really close to a corner (say 2 feet from it).

I played with it more after I posted it, I think I've got it dialed in just fine. The ultra low LFE hits in Episode II were just bottoming it out because I had too much volume on it. Turning it down and adjusting more from the reciever side seems to work great, now I rattle dishes in the kitchen and the couch gets a nice rattle as well without any sign of bottoming. I couldn't imagine an additional VTF-2 when one already sounds like this, much less at VTF-3!