My sonosub makes a farting sound (1 Viewer)

[ChristopherJ]

I built a Sonosub several months back and it sounds great with my Samson 700 amp except for the fact that I couldn't adjust the volume on it. Unfortunately, my main receiver doesn't have the ability to adjust the subwoofer volume independently. Anyway...
So I ran the sub out from my main reciever to an old receiver and am using the receiver to power the sub. I can adjust the volume and therefore can get it much louder but now I get a farting sound (the best description I can give) in most movies. A specific seen would be in the second rocket launcher/car explosion scene in Ronin with Robert De Niro. Is this my sonosub (a ported tempest sonotube) or is it my old 60?? watt amplifier I am using to power it? How can I check?
Seriously, thanks for ANY help you can provide!!!

 

[Tony Richardson]

Chris

I sounds to me that you have a leak in your sub somewhere.

I would check the driver seal and caulk all the interior seems very well, including the port. I used a whole tube of caulk on my sonotube interior seems and used a high quality gasket on the driver and it has never given me a problem except from the neighbors complaing because it is so loud and clean.

Good luck, because when you get that baby sealed up it's going to kick you ass with some of the cleanest and loudest bass you have ever experienced!

 

[Wayne A. Pflughaupt]

Chris,



The first thing that came to mind was that the driver was bottoming out. However, since this is a low-powered receiver, I doubt this is the case.



I’ll bet what is happening is that you are overdriving the receiver’s inputs. A receiver’s inputs are designed for low-level source components. Typically, pre-amp outputs are a much higher voltage, especially bass-heavy LFE signals.



A couple of things you might try:

1. Make sure you are using the sub receiver/amp's CD inputs. They often have more headroom than other inputs.
2. Try boosting the sub receiver/amp’s bass controls to the max. This will force the receiver’s pre-amp section to drive the amp section harder. Then you can reduce the main volume control. That might help.

If these tricks don't work, there is a way you could “make” the receiver function as a pre-amp and give the Samson a hotter input signal. However, you will have to be able to solder to do it.



Happy Holidays,

Wayne A. Pflughaupt

 

[RAF]

You might try playing something other than Blazing Saddles in your HT.

Sorry, just kidding. Couldn't resist. The other answers offer some good possibilities.
Happy Holidays.

 

[Mike Dr]

It could be port noise. What is the size of the port(s) you're using? .. are they flared?

 

[Patrick Sun]

I say you're clipping that little receiver's amp.

And what sort of receiver doesn't allow you to adjust the subwoofer pre-out level (from -10dB to +10dB)?

 

[ChristopherJ]

Thank you everyone for all of the input. I will likely end up trying everyone of the suggestions...it can't hurt. I apologize for not responding earlier but I was on a train ride to the North Pole (the Grand Canyon Railway in Williams AZ.) It was my 4 year olds first time to play in snow!!!
Tony, I will plug the port and try some baby powder on all the joints and seals to test for any air escaping.
Wayne, I didn't know that there was a difference in the inputs. I am using the Phono inputs and will switch to CD. I will adjust the equalizer that is built in to the receiver also and see if that helps. Can I buy an equalizer or something to hook to my Samson amp to adjust the volume and completely bypass my old receiver????
Robert, you cannot prove that Blazing Saddles has ever played on my system!!
Mike, 24" Diameter Tube, 26" Internal Height, 15" Adire Audio Tempest Subwoofer, 22" long and 4" wide Precision Flared Port (from end to end), subwoofer and port in the bottom of the sub.
Patrick, the receiver amp may very well be clipping. I don't recall hearing it do that when it was hooked up to my Samson amp. The receiver am using is a Best Buy Sony cheapo that is "Digital Ready". I use the Dolby Digital decoder in my Sony DVP-S500D DVD player to manage the bass output as in Digiyal mode my receivers controls are bypassed.
Thank you all for the great input. I am not working so I have some time on my hands and will start going through the suggestions tomorrow.

 

[Shawn Solar]

If your using the phono inputs that's where your problem lies. the phono input has a little amplifier built in to that input. Wayne's idea of switching to the cd input will most likely fix your problem.

 

[Darrin_R]

Wow, dont use the phono inputs. Phono inputs use a step-up pre-amp. All other analog inputs (CD, Tape, VCR....) on the receiver are the same and do not have the addition pre-amp stage. Any of them will do fine.

I have to disagree that the CD input has more headroom. Headroom is the reserve power that the amplifier can produce in a short burst cycle (not continuous).

Also I would not try to boost the bass on the receiver. A receivers bass control is usually always +/- 10db at 100hz. Your LFE should be rolling off well before 100hz.

 

[ChristopherJ]

Thank you everyone for the input!!! The first thing I tried was to change it from Phono to CD...FIXED!!!!!!
Even with the 60 watts?? that my old receiver puts out, it plays so much louder then ever before and without the distortion that I was getting before. This is mostly what I was hoping for when I built the subwoofer!!!!
The only remaining thing I need to know is if there is something out there that I can place inbetween my receiver and Samson amp that can be used to adjust the volume of the sub. I suspect that I am missing out by having to use my old receiver as the amp but it has the ability to turn up the volume.
Thanks again!!!!!!!!!!!