My diy 2 x15" 1KW sub isnt loud enough

[bob123]

I have built a 1kw vented sub and the bass from it is not as loud as it should be for 1kw (This is a real sub not a car one). It has 5 vents and is tuned to 25hz, The volume is about 0.25M³ (250 litres). I have used padding in the sub (the stuff avi use) is this a good idea. It is also well braced and the drivers have spl of 93dbm.
The ports are rear firing i am concerned that this would cause destructive interference of the bass.

It is running from a 2 x 500w (RMS) TOA power amplifier.

How could this be improved?

[richie00boy]

In what conditions are you using this sub? In a house that should cause severe deafness and loss of coherence, balance etc! What drive unit are you using?

At what frequency are you crossing over to your mains? What are your mains?

[bob123]

I use it for partys - Drum and Bass mainly. Some inside some outside, I need bass that makes your arm hairs move realy LOL.

The bass is cut off at 200hz, the mains have full range through a 200wpc amplifer.

I am looking to get realy pumping bass, could this be done by tuning to a higher frequency? What frequency of bass are humans most supseptable to. As it is D&B no one realy cares if it has a linear SPL. I just need it to be LOUD!
I have atached a picture of the setup.

The drivers are skytec 500w (250w RMS) per channel, I know im over powering them but they seem to be able to stand it.

The speakers look a bit scraggy and will be painted soon LOL

[richie00boy]

1. your mains are very efficient so any bass will struggle to keep up with them - imo you need 4 of those bass cabs to keep up with your mains like that
2. you are feeding the subs with too much very low frequency which is eating up valuable excursion and usable SPL - solution a sub-sonic filter
3. you will need to model the driver performance in the cabinet to see what you need to tune it to ideally to get the most out of them
4. the subs might not be up to the job - solution buy better drivers

[bob123]

SUBSONIC FILTER. What would you suggest, Do you have a circuit diagram? What frequency should it cut off?

I never thought of that but now that you mention it the drivers are moving about 2" and very little bass is noticable but the room is shaking a lot!

Thank you very much!

[BobEllis]

Bob,

For strictly party use there's not much sense going much below 40 Hz. That vibrate your chest feeling comes from 60-100 Hz.

If you need a filter board, I am running a group buy - http://www.diyaudio.com/wiki/index.p...Filter+Boards+

You can set the board up as a bandpass filter to take care of both the subsonic filter and the low pass for the sub, or you can just use the high pass for the subsonic filter.

There is a spreadsheet near the end of the thread that will help you calculate circuit values.

If you need a power supply for the boards, see the group buy section, I've got that group buy, too. both close April 14th

Bob

[Bogie]

Two drivers? Could one of them be wired wrong? Cancelling each other out?

[bob123]

No the drivers are not canceling each other out.
I have taken the the bass reflex tubes out causing the sub to be tuned to 50hz rather than 25hz. I am also considering removing the padding inside the sub. Would this increase the bass?
I will test it in a bit when my neibour goes out LOL.

[richie00boy]

50Hz tuning is too high IMO, you should be aiming for about 40Hz to avoid damage but maximise SPL.

[RobWells]

Is the whole box stuffed ? This would stop your ports working properly. Any padding should just line the walls, about 1" thick should be ok.

Definitely take it all out and try with the higher 40Hz tune.


Rob.