Cables robbing SPL?

[Kolia]

Okay so I bought a new toy last night, the famous Radio Shack SPL meter #33-4050. Hurray!

I got home and started playing with to set all my speakers to 75dB using the receiver test tone. I’ll get a “tuner DVD” soon to work on that in depth.

First finding, 75db from a sub is pretty loud compared to the rest of the speakers! Bad placement, it sounds boomy.

Second finding, in order to get the center channel to 75dB, I had to set it at -6dB on the receiver. ?!? That doesn’t make sense in my mind. Here are some basic specs for these Monitor Audio speakers:

-Fronts (RS6): Frequency Response=38Hz-30kHz Sensitivity=90 Impedance 6ohm Power Handling 120W
-Center (RSLCR): Frequency Response=45Hz-30kHz Sensitivity=91 Impedance 6ohm Power Handling 120W

Note that the center channel sits farther away but is pointed directly at the listener.

I’ve been reading about speaker cables and got a major headache out of it. My electricity class at the university was a long time ago.

Yet, cables are the only thing that is different between these speakers. I have an old set of MIT TMax terminator with coax cable for the fronts while the center uses a Z1 Monster Cable.

Could it be the MIT gizmo are robbing power?

 

[MDS]

Is the main concern a center channel level of -6 dB?

All that matters is that the SPL at your ears from each speaker is the same and you adjust the channel trims for each channel to achieve it - it doesn't matter what the actual values turn out to be. If you move the speakers slightly or move or change furnishings, the next time you calibrate you might end up with different numbers.

The center is slightly more sensitive than the other speakers and that will cause its level to be lower than the front speakers even if the front speakers were exactly in line with the center.

 

[jcPanny]

Speaker wire

Is this what you are using for speaker connections?
http://audiovision.dk/mit_tmax_onewire.htm

Any 14 AWG or 12 AWG coper speaker wire is adequate for your speaker connections, MIT, Moster, or other lables will not improve the performance. I wouldn't recommend using coax for speaker wire. The impedance of coax is 75 ohms and the area or coper is much smaller than traditional speaker wire which will compromise performance.

 

[mtrycrafts]

Yet, cables are the only thing that is different between these speakers. I have an old set of MIT TMax terminator with coax cable for the fronts while the center uses a Z1 Monster Cable.

Could it be the MIT gizmo are robbing power?

Unless there are serious issues with that cable, no, that would not cause a 6 dB spl level change.
If they are not in-wall cables, you should try plain 14ga speaker wires. Then, you have no issues to conjure up.

 

[Kolia]

Is this what you are using for speaker connections?
http://audiovision.dk/mit_tmax_onewire.htm

Any 14 AWG or 12 AWG coper speaker wire is adequate for your speaker connections, MIT, Moster, or other lables will not improve the performance. I wouldn't recommend using coax for speaker wire. The impedance of coax is 75 ohms and the area or coper is much smaller than traditional speaker wire which will compromise performance.

Yes, this is the thing. I couldn’t find any info on these anymore. The MIT web site isn’t user friendly either.

I think I’ll get “regular” cables, bi-wire all 5 speakers and be done with it. What do you guys think of the Monster Cable THX wires? 30$ for a 100’ spool is relatively cheap!

 

[AVRat]

Don't bother with bi-wiriring or the Monster cable, both are a waste of money.

 

[Sheep]

www.Monoprice.com

www.bluejeanscable.com

Don't spend a lot, get a lot.

SheepStar

 

[Kolia]

www.Monoprice.com

www.bluejeanscable.com

Don't spend a lot, get a lot.

SheepStar

Yep! Bluejeans cable underway

 

[Ampdog]

I’ve been reading about speaker cables and got a major headache out of it.

Yet, cables are the only thing that is different between these speakers?

Kolia

Don't get a headache from what you read.
[I do like to illustrate this sort of thing with an experience I once had: Not sure which motor lubricant would interfere with which (also as a result of articles) and NOT desiring to ruin my car, I phoned the oil expert at our S.A. Buro of Standards. A gentleman of obviously Scottish descent answered, and I nervously started to put my well-prepaired case. I did not get half-way, when I got a very important lesson-of-life: "Laddie, ya shouldna listen to all the old wives' tales ya hear!" (With respect to the Scots; I do really like their accent.)]

And no, the cables are not necessarily the only difference. It might be small or not - do not ignore room acoustics. You will have to be the judge of that in your case. If you want to make sure of your cables, you could check the resistance, but it would require a meter capable of measuring low resistance. Regarding effect of capacitance and inductance - see the above lesson!