Crossover frequency settings

[alastairpearce]

Hello,

I'm new to the home cinema realm, I've been more of a hifi enthusiast in the past.

However, I've just invested in a new surround system, and am looking to optimise the settings.

My system is pretty budget really:

- Denon AVR-1312 receiver

- Cambridge Audio S90 sub

- Cambridge Audio Lusso 10 satellite speakers

I chose the satellite speakers because I live in a small terraced house and didn't want to overwhelm the room (plus I've got small space and not annoying the neighbours to contend with!)

Anyway, the speakers have the following ranges:

Sub 35Hz - 180 Hz

Speakers - 150Hz to 20kHz

My questions are thus:

1. I presume the crossover should be in the range 150 - 180 Hz? This seems high compared to some recommended values of 80Hz, but I suppose this is symptomatic of the small satellite speakers.

2. The S90 sub has a dial on the back to change the crossover frequency. Do I need to adjust this dial as well as the crossover frequency, to match the settings on the receiver and the subwoofer?

Thanks in advance for your help.

 

[Lee H]

Hi there,

1. I presume the crossover should be in the range 150 - 180 Hz? This seems high compared to some recommended values of 80Hz, but I suppose this is symptomatic of the small satellite speakers.

Correct - probably around 160. 80 is an oft quoted THX figure, but in reality it's whatever your sub/speakers need it to be

2. The S90 sub has a dial on the back to change the crossover frequency. Do I need to adjust this dial as well as the crossover frequency, to match the settings on the receiver and the subwoofer?

I turned the dial on the sub all the way up and do your adjustments on the amp.

 

[alastairpearce]

Thanks for the reply - changing the settings seems to have really hit the spot.

If anything there's a bit too much bass now, so I'm going to have to adjust the respective speaker levels a bit until it's tip top, but it's starting to achieve the sort of performance I was hoping for now.

 

[sta99y]

thats great to hear!!! is sub in a corner? is it ported or sealed?

 

[alastairpearce]

Yes the sub is in a corner; it is about 100mm from the back wall and 50mm from the side wall.

And yes it's ported at the rear.

I tested the sound levels of all the speakers in turn last night and balanced the sound levels. It seems to be getting there now, there don't appear to be too many more adjustments to make before i'm totally satisfied with the sound.

 

[Lee H]

Yes the sub is in a corner; it is about 100mm from the back wall and 50mm from the side wall.

And yes it's ported at the rear.

I tested the sound levels of all the speakers in turn last night and balanced the sound levels. It seems to be getting there now, there appear to be too many more adjustments to make before i'm totally satisfied with the sound.

Chances are you bass is "booming" somewhat. Essentially, your sub is firing in to a wall and creating all sorts of reflections and reverb, which is why your bass might sound too loud. If you can, try playing with the position of the sub too.

If you've not had full cinema bass before, it can often sound too loud. Maplin sell a cheap sound pressure meter that will allow you to set all the levels properly.

 

[alastairpearce]

To tell you the truth, I used the SPL meter app for iphone to measure the test tone sound levels for each speaker.

I then balanced the sound pressure levels at the 78dB level; however from reading guidance online I understand it may be better to balance the sound levels at 75dB, as this is the calibrated sound level that the test tone is recorded at?

Once the value were balanced the bass sounded much less boomy.

I don't know how accurate the iphone sound pressure meter apps can be considered to be; if they are really not that accurate I wouldn't begrudge paying £30 for a maplin sound meter if it get's the system accurately calibrated.

 

[Lee H]

They're not great. For the sake a few beans I'd get a Maplin one.

 

[alastairpearce]

Fair enough I'll give the maplin one a go.

Would you calibrate the test tone levels at 75dB or 78dB? And does this figure really matter?

 

[Lee H]

Doesn't really matter as long as it's consistent. Mine is done to 75.

 

[alastairpearce]

I gave the Maplin sound level meter a go, and I must say I am finding it very difficult to balance the speakers to 75dB, and the results are not what I was hoping for.

I'm using these settings on the sound meter: dBC weighting, slow response.

Using the Maplin sound meter all the satellite speakers balanced at 75dBC at the following settings:

FL -3.0 dB

C -3.0dB

FR -1.5dB

SW -7.5dB

SL -3.0dB

SR -3.0dB

The subwoofer gain dial is set to 12:00.

I found it very difficut to balance the subwoofer using the Maplin meter, and when it did balance the results were very thin on the lower end and I'm not getting the base I would hope for. There was also a big difference between the subwoofer level and the other speaker levels, which I couldn't understand.

So I tried again with the iPhone app, with the following settings on the SPL meter app: dBC weighting, slow response.

This time I balanced at 75dBC with the following levels:

FL +3.0dB

C +2.5dB

FR +4.0dB

SW +5.0dB

SR +3.0dB

SL +2.0dB

To be fair, the numbers themselves are probably irrelevant to any other situation other than my own, but it just goes to show the disparity between the sound meter and the iphone, although I can't fathom the reason for the disparity.

However, with the iPhone app there wasn't such a big difference between the sub level and the other speakers, which seemed more consistent.

I've tried my hardest to keep the parameters for both tests the same, including the test position, and if I'm being honest I think I prefer the all round balance of the iPhone results, including the bass feel.

At the end of the day, it must be better to go along with personal preference over the hard numbers is it not?

 

[sta99y]

Absolutely Alastair, what you could do is cibrate the spl on iPhone with the Maplin spl meter so it will be more accurate. I use the iPhone spl and think its good enough for 69p. Do a google search on "Crawling for bass" then follow the steps. It's a beth interesting subject.

Glad you're getting more satisfied with you're setup.

Its a shame no one nearby on the forums offer setup help if they are local.

 

[fr0g]

With a crossover of 160 Hz, you are best keeping the sub within a couple of metres of each speaker to avoid directionality of bass.

See here...

http://www.sengpielaudio.com/calculator-wavelength.htm

 

[alastairpearce]

I've read several set up guides online which say that the sub should be set up approx +5dB from the main speakers - this would seem to fit in with the set up that I have found most pleasing.

Also, with the size of living room that I have (typical small London terraced house) it would be difficult to get the subwoofer more than a couple of metres from the main speakers anyway without putting it in a different room.

Unfortunately, I'm quite limited due to space restrictions on where I can position the sub; obviously I wouldn't want it in the middle of the floor as it wouldn't make a very good coffee table.