VX-10 In room response curve

[Guiria]

I've created an in-room response curve of my VX-10 using the following:

RadioShack digital SPL meter placed on tripod
AV123 bass test tone cd adjusting pink noise to 60 db as instructed by AV123
Table I created in Excel to log the test tone data

Attached is the graph. I'd be interested in some of your interpretations of the graph. Especially about why the upper frequency tones of the sub are so weak. I'd also like to know if there are any additional steps that should be taken when plotting response curves. Keep in mind I'm just an enthusiast and I'm not interested in super calibrated SPL meters and expensive software

My interpretation is this.
The sub does not have a lot of output reaching only 75 db during the test. AV123 said that in some frequencies the sub should reach 80 db, I never saw that. The output beyond 78 Hz is weak. The graph reflects a slight boost in db (about 6 db) from my bookshelves. The sub alone looked worse without the bookshelves kicking in at 100 Hz. Obviously there is a room null around 85 Hz.

The sub is in a room 15x19x8. I think it is underpowered to deliver reasonably powerful sound across its rated frequency range of 36-120 +/- 3 db inside a room that large (2280 cubic feet). Now if only my wife would buy into an argument for a new sub with some data backing me up...

 

[Sheep]

Could you possible spread the graph out a bit? It's hard to see the volume and frequency.

SheepStar

 

[Bassman2]

I don't know if this makes a difference to your situation but I keep my X over all the way up and use the x over in the receiver instead. That last little bit noticeably bumps up the higher frequencies, even with the amp crossover set at 80 or 90hz.

That's interesting though, I'd like to hear what others say. It was nice to see however that there is some life below 36hz.

 

[Bassman2]

One other thing, is your VX-10 one of the ones I've heard about that require the preamp output level to be turned way up to get adequate volume from the sub? I've read this in a few reviews but don't have that problem on mine. The receivers sub output is only about half way up. The sub itself is set at less than half. Any more and it starts drowning out the speakers.

 

[Guiria]

I currently use the xover set at the receiver and not on the sub. The volume on the sub is turned up to about the one o' clock position.

I did have the low volume signal problem, however, on an older pioneer receiver of mine. I now own the HTR-5960 and I do not have the problem of the sub receiving enough signal and in my receiver the volume trim is below the 1/2 mark.

 

[Guiria]

new zoomed in response curve

This response curve is zoomed in with minor gridlines added. Hopefully it's a little easier to see whats what

 

[Bassman2]

I currently use the xover set at the receiver and not on the sub. The volume on the sub is turned up to about the one o' clock position.

I did have the low volume signal problem, however, on an older pioneer receiver of mine. I now own the HTR-5960 and I do not have the problem of the sub receiving enough signal and in my receiver the volume trim is below the 1/2 mark.

OK, mine's at 11:00 and just over half at the receiver (RX-V659)

 

[jcPanny]

Receiver crossover setting

Try lowering the crossover setting on your receiver to 80 Hz to reduce the null in your response. Unless you have small satellite speakers, they should easily play down to 80 Hz. You also might be able to experiment with sub locations and how they effect the response.

To improve the sub auto turn on, increase the sub db level on the receiver and turn the sub volume knob down to compensate. The sub line level input will get a higher voltage from the receiver and turn on properly.

 

[Guiria]

Try lowering the crossover setting on your receiver to 80 Hz to reduce the null in your response. Unless you have small satellite speakers, they should easily play down to 80 Hz. You also might be able to experiment with sub locations and how they effect the response.

Excellent suggestion...I'm trying that tonight.

 

[j_garcia]

Looks like it is intended for a smaller room based on your numbers. Response isn't too bad overall, but that dip is definitely an issue. I had something similar with my PB-10, with a huge dip around the x-over frequency. I sold it and bought a new sub though and the new sub didn't have that dip in my room.

 

[Guiria]

setting the xover at the receiver to 80 Hz made a huge difference. The null is gone. Before, the null at 80 Hz was 55 db. Now with my bookshelves kicking in a little lower the frequency is 66 db at 80 Hz...that was easy.

 

[Sheep]

Are you sure the Second graph is 60db? It reaches up to 75....

Down that low, 25Hz isn't going to be very audible, usually 80-85dB is where i would cut it off.

SheepStar