View Full Version : 20-39pc+
07-29-2004, 09:27 PM
Just bought a 20-39PC+ and received it today. Set it up as per instructions and calibrated the system with an SPL meter. I am very dissappointed. At higher volumes I can detect an audible rattling in the cabinet with CDs and radio. I can't locate the source but it is definitely coming from the subwoofer unit. No lose fittings around the woofer itself. It is not through the floor or walls either. I contacted the SVS tech staff and am waiting for a reply. I am so upset. I've been waiting all week and now may have to send it back. Any ideas on what could be wrong?
07-30-2004, 02:11 AM
call SVS technical support first. They may have incountered this problem with someone else. I would do that before sending it back to get looked at.
I hope mine does come that way. I am purchasing a 20-39 Pci tomorrow. I can't wait to get mine!
Loud & Clear
07-30-2004, 03:54 AM
Cabinet? Not sure what that means on the 20-39 PC+. Might the grill not be snug? I also own one, and I'm having a tough time imagining "cabinet" rattle.
I am, however, sure that you'll get this problem straightened out by simply calling SVS' customer support and talking the situation out. Once you're through with that, you're going to LOVE your sub. Hang in there and get it resolved.
07-30-2004, 07:22 AM
Did you give the sub a little shake to see if there is something inside that might have been left inside or come loose during the assembly? you can take one of the ports out to look inside it could be an extra nut or a nut may have fallen out during assembly.
07-30-2004, 09:29 AM
When I say cabinet, I mean the cylinder housing. I have done everything from shaking the unit, to moving it, to holding down certain parts (grill, woofer, ports) to make sure all is secure. Customer service told me to contact tech support which I did. No resolution yet.
07-31-2004, 05:26 PM
If the sub is on a hard surface, it might be bouncing up and down and the baseplate is vibrating on the floor, despite the stock rubber feet. Try the optional 3M ruber cupped feet and see if that cures it.
Also, UPS has been known to damage subs in transit and may have knocked something loose or even damaged the driver.
If the cupped feet don't fix the problem, tech support will take care of it.
08-03-2004, 08:50 PM
Originally posted by Dr. Spec
If the sub is on a hard surface, it might be bouncing up and down and the baseplate is vibrating on the floor, despite the stock rubber feet.
I currently have my 20-39Pci on a wood floor upstairs until the HT room is done and this is exactly what was happening to mine. So I put it on a carpet square and problem solved.
08-04-2004, 09:54 AM
For some reason, the rattle has stopped spontaneously. However the sub seems extremely boomy to me. I am frustrated as well with the lack of midrange. My LSi9(s) fronts are tied to this woofer. The sound is less then impressive in the midrange. I used an spl meter to calibrate the system and still can't believe I have spent over 2000 dollars on a system that doesn't even compare to the sound I get with my infinity sm102's on my system up stairs using essentially the same receiver. What am I missing?
08-04-2004, 11:39 AM
what is your subwoofer crossover set at? that may have some effect on the sub being boomy.
also.. turning the sub volume on the rear of the sub to about 12 0'clock is where you want to be at.. lessen the knob to 11 or 10 o'clock if it still seems boomy. also on the rear of the sub amp there is a toggle switch for the crossover. to enable or disable it. that will have an affect on the "boomyness" of the sub too.
don't give up... SVS subs are incredible.
good luck. hope that SVS tech service can help you figure it out.
08-04-2004, 11:42 AM
Originally posted by adiodato
My LSi9(s) fronts are tied to this woofer. The sound is less then impressive in the midrange.
what do you mean here? your LSi 9's are tied to this woofer?
I wouldn't run them this way.. run the SVS with a RCA cable from your receivers sub output. and hook your LSi 9's to the left and right speaker front outputs.
08-04-2004, 11:59 AM
What are your receiver settings?
I would set sub to yes, x-over to 80Hz, fronts to small, run rca cable from sub out on the receiver to the sub. Run speaker wires directly from the receiver to the 9's. Re-calibrate and enjoy.
08-04-2004, 01:26 PM
Boomy bass is usually a result of a large peak somewhere in the 45-55 Hz region. Also, a resonating floor can create its own "sound" and add to the boom; that's why I prefer concrete flooring. You might try a concrete paver under the sub and see if it tightens things up.
Room acoustics and the FR at the listening position play such a huge part in the SQ of the bass. If you don't know the FR of the sub at the listening position, even calibrating with a DVD is a shot in the dark (although way better than nothing).
And the calibration disc makes a big difference too. Aside from the fact that DVE has a 10 dB encoding error, the spectral distribution of the DVE sub signal is vastly different looking than (for example) the Avia subwoofer signal. Depending on what is happening in the room with respect to peaks, nulls, and overall extension, the calibration disc itself can contribute to the problem.
The FR of the 20-39PC+ in the 20 Hz tune is virtually a flat line from 100-19 Hz when measured outside. I should know, I just tested one about 2 weeks ago. If the 20-39PC+ sounds rotten in your room - trust me, it's the room and not the sub.
I suggest you measure the FR at the listening position with burned test tones, and SPL meter, and a spreadsheet with correction factors. Several members here can help set you up with this procedure. Once you see what is happening in the room, you can experiment with sub placement, phase control optimization, isolation pavers under the sub, moving the listening position, etc. Eventually you will find a combination that delivers the clean, flat, deep, and accurate bass SVS is justifiably known for.
08-04-2004, 01:49 PM
Thanks for the replies. I appreciate the input. Currently my floor is concrete. The front speakers (LSi 9)s are set to large, so I will make the change and also change the crossover to 80 from 100. I don't understand what FR is? All of my testing has thus far been done with music CDs not DVDs. Is it possible that good audio is simply not as attainable without larger loudspeaker (i.e. not bookshelf)? My receiver is an Onkyo TSR-800 (100 watts x 7). I wonder if the LSi9s simply steal to much power from this more power conservative receiver.
08-04-2004, 03:16 PM
Definitely set the LSi9 to small with an 80 Hz xo and the sub to on/yes.
FR = frequency response. If the FR is not flat (it has peaks and valleys), the sub will sound bad. If it sounds boomy and "one note"-ish, there is probably a large peak in the response around 40-50 Hz.
08-04-2004, 06:25 PM
Don't forget to check the recievers sub setting (-5) to get a clean signal from the reciever to the sub. For some reason while I was goofing with the speaker settings I moved the sub setting to -1 and it sounded like crap simular to those heard from little kids and their car systems at red lights. Even if you adjust the gain on the sub the sub will still sound like crap because of the rough signal it is getting.
Originally posted by adiodato
All of my testing has thus far been done with music CDs not DVDs.
How did you calibrate the system? If you are using DVD calibration discs such as AVIA or DVE, your sub is way too hot for music. If this is the case, back the sub gain from the receiver at least 6dB for music sources and try if you like it better.
08-04-2004, 09:49 PM
So there is nothing/wrong with/inside the speaker - it is vibrating on your concrete floor?:confused:
08-04-2004, 09:58 PM
100 watt oinker receiver driving lsi9's? :confused:
08-04-2004, 10:59 PM
NO the concrete floor was never the problem. The rattle is now gone after replacing the driver. When I last set the db it was at negative 1, so thanks dave I'll cut back to -5. Is the receiver to weak to fuel to LSi9s? Is that why the midrange is weak. Is that what others believe. When I said the speakers were tied to the woofer I meant paired with, not actually having the speakers running through them.
08-04-2004, 11:02 PM
Originally posted by adiodato
wonder if the LSi9s simply steal to much power from this more power conservative receiver.
if this is the case.. it would not affect your subwoofer. and causing it to sound boomy. subwoofers, most anyways. are powered. and take no power away from your reciever. it has it's own power supply. thats why it plugs into the wall.
I'm thinking it's boomy because it's the wrong settings somewhere. I also hear you saying that the sub isn't providing good mids... i'm not a bass expert.. but I don't t think my SVS is suppose to provide much midrange tones. Usually only the lower bass frequecies. I could be wrong. I'm not certain how much mids a sub is suppose to provide.
It also sounds like you're not happy with the sound coming out of your LSI9's. You may need a seperate two channel amp for those speakers. Say one that is 200wpc @ 4ohms or better.
08-04-2004, 11:06 PM
Thanks for the response danger. The sound from the LSi9s seems to be more the problem now then the sub. Your right, I need to tackle the setting of the sub a little more. I just wish the guys at polk would have told me the LSi9s demanded a more powerful receiver. It almost seems worth it to sell the LSi9s and downgrade to a more efficient speaker to match the receiver. The cost of this thing is just getting out of hand.
08-04-2004, 11:13 PM
maybe the RTi6's or Monitor 40's would be a better match for your receiver if you want to stay with a bookshelf size speaker.. they are not so power hungry as the LSi line is.
Would you ever consider a floor standing speaker? Some of Polks floor standing provide excellent midrange. and will offer you more bass as well. Just a thought here.
08-04-2004, 11:18 PM
I think if I go back, I will go for floor standing speakers.
08-05-2004, 09:12 AM
seems to me if the cost is getting out of hand he would be better off getting the rti6's. He would be able to drive them with his current receiver and should get pretty good mids and highs from them. Combine that with the SVS for the lows. He should be pleased. (at least that is what I am hoping for when I get my SVS :D )
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