Galaxy CM-140 range (Newbie Question)

**Graham N** · **07-28-08, 10:44 AM**

Hi all,

I have just ordered a PB13 Ultra. I expect I will have some REW and Behringer related questions for you later.

For now my query is related to the Galaxy. There probably is an easy answer but it doesn't make sense to me as I have no idea how this all works apart from trying to follow idiot proof instructions.

The question is if your sub goes down to 15Hz or even less how is the Galaxy any good for taking measurements when it is rated as 31.5 Hz to 8kHz?

Thanks for the answer,

Graham

**tonyvdb** · **07-28-08, 10:50 AM**

First of all, Welcome to the Shack Graham!

As with most SPL meters you use a calibration file to correct the readings this is available with REW and should be selected before running the test but also generally the measurements below 30Hz dont have much effect on your room response. The area that usually causes problems is in the 40 to 80 Hz range or just around the crossover frequency range.

**Graham N** · **07-28-08, 11:12 AM**

Quote:

tonyvdb wrote:

First of all, Welcome to the Shack Graham!

As with most SPL meters you use a calibration file to correct the readings this is available with REW and should be selected before running the test but also generally the measurements below 30Hz dont have much effect on your room response. The area that usually causes problems is in the 40 to 80 Hz range or just around the crossover frequency range.

Hi Tony,

thanks for the prompt reply.

Graham

**brucek** · **07-28-08, 01:16 PM**

Take the time to read the REW HELP FILES and the REW Connection and Cabling Basics. It will help you a lot.

brucek

**Graham N** · **07-28-08, 01:48 PM**

Quote:

brucek wrote:

Take the time to read the REW HELP FILES and the REW Connection and Cabling Basics. It will help you a lot.

brucek

Thanks for the links brucek,

It all looks a bit beyond my capabilities to be honest, so it may be money wasted on all the equipment required. Also with regards to the choice of meter. On the links it shows the Radio Shack meters as being suitable but in the forums it seems to suggest that there is problems using these and the recommendation is to go for the Galaxy CM-140? I can get the RS ones easily here in the UK but not the Galaxy. (Not for reasonable money anyway (E-bay £103)).

My PB13 Ultra will be here tomorrow, with regards to the peq adjustment, do I need all this gear to be able to make adjustments using peq. In other words is there an idiots guide to setting up this sub without any extra gear?

thanks,

Graham

**salvasol** · **07-28-08, 01:55 PM**

Quote:

Graham N wrote:

On the links it shows the Radio Shack meters as being suitable but in the forums it seems to suggest that there is problems using these and the recommendation is to go for the Galaxy CM-140? I can get the RS ones easily here in the UK but not the Galaxy. (Not for reasonable money anyway (E-bay £103)).

Welcome

Just get the RS meter ... if you'll use it to calibrate just the sub is fine

The problem with RS is that is not reliable above 3K-5K ... but for just the sub is fine, and cheaper too

**jaspal kallar** · **07-30-08, 06:11 AM**

Quote:

salvasol wrote:

Welcome

Just get the RS meter ... if you'll use it to calibrate just the sub is fine

The problem with RS is that is not reliable above 3K-5K ... but for just the sub is fine, and cheaper too

I'm new here also. I'm in a similar position living in Europe (Sweden). I've only a 2 channel set up, no sub and the amplifier is integrated.

My speaker (kef 103/4) specs say:

Effective Frequency Range:

50Hz - 20kHz ± 2.5dB, -6dB at 38Hz measured at 2m on reference axis

Directional Characteristics:

Flat within 2dB from 50Hz - 17kHz up to 30º off reference axis in any direction

Okay, does this mean I can use the Radio shack SPL?

Cheers
jaspal

**brucek** · **07-30-08, 07:13 AM**

Quote:

does this mean I can use the Radio shack SPL?

Tell us what you plan to do with the Radio Shack meter... what is the goal?

brucek

**jaspal kallar** · **07-30-08, 11:55 AM**

Quote:

brucek wrote:

Tell us what you plan to do with the Radio Shack meter... what is the goal?

brucek

I have no room treatments in my room at the moment.

I want to find what modes are effecting my room so that I can better buy suitable acoustic room treatments accordingly. I want to know how much echo is effecting my room (that is a problem I already experience today).

After adding room acoustic treatments I would like to use REW again too check if the acoustic treatments have made any measurable difference, although I will use my ears as well

I don't intend on moving my speakers around. My living room is my hifi room.

Cheers
jaspal.

**tonyvdb** · **07-30-08, 12:12 PM**

Hi jaspal,

one really simple room treatment that makes a huge difference if you dont have carpet in the room is by placing a throw rug down on the floor this will absorb allot of reflection. I have even seen people put one on a wall and actually looks quite good.

**jaspal kallar** · **07-30-08, 02:13 PM**

Quote:

tonyvdb wrote:

Hi jaspal,

one really simple room treatment that makes a huge difference if you dont have carpet in the room is by placing a throw rug down on the floor this will absorb allot of reflection. I have even seen people put one on a wall and actually looks quite good.

tonyvdb, thanks for your tip. My floor is wooden (typical here in Sweden) and do infact have a large rug. I was thinking of putting a rug on the back wall as well... maybe later after I've done some measurements

cheers
jaspal

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