setting up my subwoofer


Active Member
Well I went out and purchased my subwoofer a Monitor Audio asw1000. I`m
trying to set it up with my Sony str-db925 amp. I cannot find my original
instructions for the amp. I have set the subwoofer to on. But trying to make
head or tail of the frequencies. Has anyone got a guide for this?
Also trying to set a good level for the base by messing with the gain,
frequency and phase but are playing in the dark.
Any help?



Standard Member
Perhaps a picture of the sub's controls would help but here goes with a rough guide anyway.

Phase Control - This can either be a toggle switch with normally 0-180 as choices or it can be a dial with a range starting from 0 and finishing with 180. The phase control is important for setting up the sub to match the other speakers in your setup. For instance if you position the sub behind you but the front speakers are 3 metres in front of you then the bass output will not match, the phase control enables you to match the delay of the sub's output to more closely match the other speakers. A good test I've found for this is to play a soundtrack like Blade (opening rave scene) with a fast pumping bass track, an incorrect phase setting will make the thud from the sub come after the thud from the speakers creating a horrible sound, adjust the phase till the thud from the sub is at it's closest to the thud from the speakers (tightening the bass).

Frequency Cut Off - It would help a lot if you could state your hardware but again I'll try and give a rough guide. If you have a THX amp/pre&power then it has it's own sub cut off of 80Hz. If your sub has an option to turn the frequency cut off to "Off" then choose it and let the amp take over. If you can't turn the cut off point off then choose "80" Hz from the dial. With a non-THX amp you should ideally still try and keep a cut off of 80Hz, set the speakers to "Small" in the settings. I've found that even if you have powerfull main speakers a setting of small to allow the sub to handle the bass gives better results.

Sub's Volume - This one is easy if you are prepared to put the time in. Find a DVD that contains a bass heavy soundtrack (Godzilla/Independence Day/Titan AE etc) and from your listening position turn the sub's volume dial to the point just before any boomy bass occurs, that will be the starting point. Now you MUST try the subwoofer in diff locations to find the point where you can actually increase the sub's volume without any boomy bass, the point in the room that allows the greatest amount of bass with the lowest amount of boom/distortion is the sub's sweetspot. That method actually took me about 3 weeks to finally discover the sweetspot and when you do find it you will be very pleased at the results as I was.

If you list your hardware and any relevant pictures/specs of the sub's controls you'll get a more detailed answer from the real experts on this forum. I'm no expert in anyway, the above constitutes what I've picked up from using diff subs over the years and has always worked for me.


Active Member
As I say the amp is a sony str-db925 with Tannoy m3 floorstanding at front and m1 at rear with the Tannoy mc as a centre speker. Thanks for you help so far guess I shall be playing for a while.


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