SUB THREE sensitivity setting for equalization?

[Robertsmania]

I own a pair of SUB THREEs and its been a little more than six months since I first did the low end equalization.  I did let them break in when they were new before doing the first pass but now that they've been in heavy use for a while I wanted to run through it again.

I see now that there is a manual for the subwoofers, which was not available when I purchased mine:
SUB THREE MANUAL

There is also the setup worksheet:
Vandersteen Setup Worksheet for the SUB THREE and Original Vandertones Test Disc

This video on YouTube is also very helpful with Richard going through the similar process on a pair of Model 7s:
https://www.youtube.com/watch?v=7C60LoHGtI0

 

My question is about the sensitivity setting while performing the bass equalization.  

When I did it the first time, I had it set at "noon" which reads 90dB on the dial.  

Is that indeed correct?

 

I only ask because now that there is a manual, I see that it states:

Quote

3. On the SUB THREE Amplifier set the low frequency contour control to minimum (#1) and verify that all eleven room compensation band are set straight up (slot vertical). Set low frequency level to 0dB.

And the worksheet says:

Quote

-woofer Level set "0" and Contour "1".

I suspect its just a difference in the way the various speakers label the Sensitivity/Level dial and that the documentation is largely duplicated from the instructions on the other products.  But since we do the adjustments with a target of 70dB it does cause me to wonder if the sensitivity should be turned all the way down to be in that range rather than up at 90dB?

[Richard Vandersteen]

This is an error in the manual.  It should say to set the woofer sensitivity to the what ever the main speakers are.  This is not hyper critical as the Sensitivity (level) and Contour will be adjusted by ear with a standup bass recording (track 13 and 14) anyway.

RV

[Brad O]

Thank you for pointing out these errors.  Both the manual and the setup sheet have been updated for download from the website.

[Robertsmania]

Splendid, thank you for the prompt reply and corrections!

I'm going to use 86dB on the Sensitivity since that's where I've had it set since adjusting the user controls after the first calibration.

The next question I have is related enough that its probably okay to ask in this thread rather than start a new topic.

What's the correct way to read the sound level meter with the warble tones on the fast response mode?

Here's a short video to demonstrate what I'm seeing doing the initial readings of track 9, 10 and 11 to get their average to 70dB.

To be honest, when I did this the first time I somehow missed the instructions for using Fast and did the calibration with the meter in the Slow response mode.

Looking at how the needle moves in the Fast mode, I'm not sure if its best to say the value is the midpoint in the swing, or the peak?

Or is there user error with how I'm trying to do the measurements and the needle really shouldn't be moving around that much?

 

 

[Richard Vandersteen]

Warble tones by design warble!  You are looking for the average but not unusual peeks as they are noise and evidence digital meters are always wrong.  This is true because the obvious unusual peeks are still averaged into the reading but are corrupted.  It won't take long to know what the real answer is.

RV

[Robertsmania]

Thank you for the replies.

I've gone through the process a couple times in the last few days and feel pretty comfortable with it now and have a better intuition for how the adjustments may be affecting their neighbors.

Also using the fast setting on the sound level meter does seem like I can get a good sense of what the average reading is in spite of the swinging needle on the warble tones.

 

Previously, I had been running my M5-HPB set with switches 2,8,9 ON (undocumented setting) which crosses over right at 80Hz with my Sunfire TGA-5200 amplifier as verified with the  volt meter testing.  0.732V@80Hz with 1.022V@1000Hz.

In this pass I've changed the crossovers to use switches 1,8,10 ON which crosses over just above 100Hz.  0.712V@100Hz with 1.019V@1000Hz.

 

The first time I did the equalization, the subs were set at 90dB Sensitivity but I ended up turning them down a bit to ~86dB when adjusting the user controls.  This time, I experimented with doing the equalization lower and ended up doing the final pass with it at 84dB.  The difference may be negligible, but I think it sounds better to do the equalization a little low and adjust up to match the mains.  

Listening to it now, I'm very happy I went back through and re-did the equalization.   I'm going to run it like this for a while and continue to evaluate, but my initial response is that the 100Hz crossover sounds fine and pulls the subs into the room a bit more.

[Robertsmania]

The other suggestion I would like to make for people doing this on their own is to be able to see the SPL clearly from the sub across the room.

I had really good results attaching a webcam to the SPL with some thin plumbers tape that bent easily for adjustment.

Using a long USB cable to my laptop it made it easy to see the meter and adjust the pots at the same time.

[TomicTime]

don’t over EQ..perfectly flat is the  enemy..

great Mcgyver work on remote view…..

Facetime w two devices can also work

[ctsooner]

Wow. Now we are getting technical.  I can envision Richard setting up a device like that to test and set up. Lol.