Phase setup help?

[Timh]

I have owned a Monolith for a couple of weeks now, and have found setting the phase not as easy as I thought it would be
The subwoofer is on the same wall as my main speakers but in a corner.
I have just set the phase playing Queens "One year of love" as this track has a slow repetitive base thump.
I started at 0 deg which is what it has been setup at since it was first installed.
At 0 deg I found it far to boomy but then moving to 180 deg I found that the base from the subwoofer vanished
I then set it midway at approx 90 deg which seemed to be the best compromise (but with less base).
Have I done this correctly?

All speakers set to small with freq being handled my my amp set to 80Hz.

 

[eviljohn2]

You need to make sure you listen in your seat rather than with your head over the sub changing the values. It's best to set the phase such that the sub is at it's loudest setting and then turn the gain down if it's booming too much.

In fact, turn it down anyway. Less is definitely more although it can take a little while to come to that conclusion.

 

[Timh]

In fact, turn it down anyway. Less is definitely more although it can take a little while to come to that conclusion.

The Sub is already set to the same level as my mains, so would it be ok to reduce the gain to a lower level than the mains?

Thanks for your help

 

[eviljohn2]

Did you set them up using an SPL meter or by ear? If it was by ear then definitely turn it down a bit.

If it was with an SPL meter then bear in mind that if you have any large peaks from your room (which will be affected by phase) then it can skew the SPL reading a bit.

People shouldn't be afraid to turn decent quality subs down a bit as you're really not going to miss the good bits when they can still let loose. It's the cheaper ones where you need to have it a bit louder to compensate for them not being very good.

When I set my equipment up I set everything to the same level using an SPL meter. Then tamed the peaks using a BFD and then set everything to the same level again. My final step is playing a music track (The SLF cover of Doesn't Make it Alright on the John Peel live collection for anyone that knows it) and this usually results in me cutting the bass a fraction more.

 

[Timh]

Hi John

Yes I did use a SLP meter, if anything the sub was set just below the level of the main speakers.
I still think its a bit loud though, so i guess I will have to drop it a couple of db.
Strange as many people on this forum seem to have thier sub set a couple of db above the mains, maybe because its the smaller sub they are using.

ps. thanks for the firefox search plugin for avforums
IE is pants long live firefox

 

[eviljohn2]

If you think it's a bit loud then drop it until you're happy. Having tried that you ought to put a dramatic film on (LOTR battle sequence if you have any of them ) and see for yourself if you're actually missing out on anything.

Since you have an SPL meter have you thougth about plotting a graph of your frequency response? One set of results wouldn't take too long and would definitely help get an idea of where any boominess might be arising.

I used to have my subs a bit hot when I first got them because it's fun but the novelty quickly wore off and just became tiring to listen to. It can take a lot of effort to get the sub right but once you have you'll realise that it was worth all of the effort.

 

[Timh]

Since you have an SPL meter have you thougth about plotting a graph of your frequency response? One set of results wouldn't take too long and would definitely help get an idea of where any boominess might be arising.

Hi John

How would I go about plotting a graph.
Is there an idiots guide to doing this anywhere?
I thought everybody owned LOTR Trilogy

Thanks

 

[Ian J]

Is there an idiots guide to doing this anywhere?

No idiot's guide but Nimby's guide may be close enough and is a sticky here at the top of this forum.

 

[Deleted member 30535]

Over the weekend I lugged my desktop into the lounge to use the souncard to hook up to my RadioShack SPL meter. I took a little while to get the calibration right using the "ROOM EQ WIZARD" http://homepage.ntlworld.com/john.mulcahy/roomeq/index.html
which is free and works a charm.

Once I was happy that the results I was seeing were the same as I was taking manually, it was soooo easy then to get a responses using a frequency sweep on my speakers and sub. Within a couple of seconds it was easy to plot your response with phase set at different settings. With the sub on its own there was little difference in the peaks I saw, but with the mains on as well (using an array of phono plugs & connectors from the pc to the amp) it was as clear as night and day as to which phase was best.

It was also easy to move the sub around the room and gauge the response for different positions. What suprised me the most is that by pure accident my seating position is the best I could find. Just moving the SPL meter forward by 20cm and 40 cm large troughs appeared in my FR. SO all I need now is my BFD that I've ordered and I'll be taming the peaks caused by the room at 26-28 Hz. (+15 db too hot).

With the right leads/adapters tpo get sound in and out of your pc line-in line-out (don't use microphone or headset sockets) you can get some real good data. My only gripe was the set up and calibration which requires you to loop the left out to the left in on the soundcard with the SPL meter on the right in. I found the set up worked with the meter on 80db range and the reference source set to 83 db (amp at -2db with Avia wideband pink noise on 5 channels).

Good luck!

 

[Timh]

Thanks Malice.. I will take a look at the software.