non SVS sub question

phoneisbusy

Okay, I'm jealous! The church organ music thread results has me droolin' but a new sub is not in the cards. I do have a generic $200 sub that a friend hooked me up it. For the price, I believe it's good value. The cabinet is well made and heavy as hell.
It's a 12" woofer, port on the bottom with a 150W amp and they gave me a remote (well, I actually don't use it).

I've got a SPL meter on the way so I can measure/benchmark properly and I have Dr. Spec's handy spreadsheet.

I downloaded the sine waves from 100 - 10 Hz and tried it last night. My question is what is reasonable performance from a sub?

It plays the tones from 100 down to 31.5 Hz very loud and clear. The volume begins dipping significantly at 25 Hz (it's subjectly about half as loud) and you can't hear anything below 25 hz although some knick-knacks by the sub rattle.

Just curious if there are any tips I should be aware of when I try and measure the SPL this weekend?

Thanks

Dave

Dr. Spec

Advice?

Don't play the tones too loud or you will fry the VC on the driver. I use about 80 dB at 100 Hz as a starting point.

And the RS meter needs correction factors. My spreadsheet probably has them, but I have a few versions floating around so make sure the one you have has the RS meter correction factors.

Based on what you said, the sub is probably tuned at around 35 Hz, and with room gain you will see extension to around 32 Hz. Below that it will drop off at 24 dB/octave (i.e., pretty steeply). So your subjective impressions about a significant loss of output at 25 Hz make sense.

The organ recordings (if you have them) have 16 Hz content, and you probably won't feel anything from the sub at those ultra deep frequencies.

Doc

Pauly

can i get a copy that RS Spl meter SS?

paul_pelletier@verizon.net

Thanks

phoneisbusy

Originally posted by Dr. Spec
Advice?

Don't play the tones too loud or you will fry the VC on the driver. I use about 80 dB at 100 Hz as a starting point.

...

Based on what you said, the sub is probably tuned at around 35 Hz, and with room gain you will see extension to around 32 Hz. Below that it will drop off at 24 dB/octave (i.e., pretty steeply). So your subjective impressions about a significant loss of output at 25 Hz make sense.

Doc

As always, thanks for the suggestions Doc.

Is 35Hz a typical tuning point for subs? Just curious as to how this sub stacks up to typical low/mid range consumer subs (no illusions of this kicking any sub's butt here... ).

I've head of Polkster's plugging the ports to get a bit lower extension and/or using granite plates under subs on carpet. Are these tweaks applicable to most subs?

regards

Dave

Dr. Spec

Originally posted by phoneisbusy
As always, thanks for the suggestions Doc.

Is 35Hz a typical tuning point for subs? Just curious as to how this sub stacks up to typical low/mid range consumer subs (no illusions of this kicking any sub's butt here... ).

I've head of Polkster's plugging the ports to get a bit lower extension and/or using granite plates under subs on carpet. Are these tweaks applicable to most subs?


regards

Dave

Sure...this sounds like a PSW450 type sub - 12" driver, 150 watts, ported. 35 Hz is a pretty standard tune for an entry level sub like this.

You only have one port though, so I wouldn't recommend plugging it - the sub might not respond properly because the T/S parameters of the driver might not be appropriate for an acoustic suspension application.

The slab under the sub is if you have a wooden floor that booms. The slab can help decouple the sub from the floor and reduce boom. The A/C unit concrete pad for less than $10 works well.

gatemplin

For what its worth, I tried plugging my 202 and wasn't an improvement. It sounded like it was straining.