New Subwoofer Recommendation

**kberg** · 01-20-2003 09:24 AM

Hi guys,

I'm interested in the SVS line of subwoofers. I've read all of the threads on sub recommendations, so no need to refer me to any of these threads. I just was soliciting for recommendations on what SVS sub would be a best match, given the bass output of MY current speakers (see profile). Room size is roughly 17' x 22'.

Opinions/suggestions welcome. Seems to me I would need one of the PC rather than the CS series, as I do not have or want to supply separate power.

Dr. Spec? Others?

Dr. Spec - haven't forgot about you on getting you feedback on my Infinity sub, in terms of determining at what point dB-wise my sub just begins to not sound "clean".

Thanks in advance.

Kevin

**Dr. Spec** · 01-20-2003 10:56 AM

I run my RT800i (essentially the same speaker - output and bass-wise as the RTi70) on SMALL with the receiver filter at 80 Hz and the filter disabled at the sub.

In that size room, if you want really powerful bass to "live the war movies", the PC+ is your guy. That's a big room. Try to corner load the sub along the same wall as the mains. Mine is not quite corner loaded, but is close enough. Try to stay within 10-12 feet of the sub for maximum SPL.

Ron S and Tom V over at SVS will steer you in the same direction, I'm sure. Their Cust. Service is outstanding. It pays to ask them before final purchase. Email Tom V a room diagram. Copy Ron in and tell 'em I sent ya!

Tomv@svsubwoofers.com
rons@svsubwoofers.com

**kberg** · 01-20-2003 11:09 AM

Sounds good. Yeah, my RTi70's are set up the same as your mains and they sound great.

As usual, thanks for the reply. So, it sounds like the 25-31 PC-Plus or 20-39 PC-Plus would be the ticket. Just have to decide between these two and more importantly, save up the bones to buy it! Before purchase I will certainly contact Tom/Ron for their advice.

**Dr. Spec** · 01-20-2003 02:23 PM

Originally posted by kberg
So, it sounds like the 25-31 PC-Plus or 20-39 PC-Plus would be the ticket.

The 25-31 will play the loudest of the three above its tuning point of 25Hz. It is the best choice for people who want to eek out that last dB of output for music and most movies.

The 16-46 has the absolute deepest extension. In exchange for that, its overall maximum output is about 3 dB less than the 25-31. In its stock tune (all three ports open) the 16-46 will capture 99.9% of the SS content on any DVD.

The 20-39 is the pinch hitter of the line-up, a really good mix of extension and sheer output and the best selling enclosure size. With all three ports open, you can expect a 20 series to have an in-room F3 of about 16 Hz if you have the SS filter set at 16 Hz. This practice is perfectly safe for sane volume levels, but if you are REALLY pushing it hard, set the SS filter to 20 Hz to prevent woofer bottoming below the tuning point.

Just for fun, I have tuned my 20-39 with one port plug and the in-room response stays flat to 11 Hz if I set the SS filter to 12Hz. With one port plugged, you lose about 2-3 dB of max output capability.

If you have email listed, I'll send you my FR sweeps with various phase and tune settings.

Remember, we are talking in relative terms. Even a 16-46 will get damn loud in your room. The smaller guys will get just a bit scarier.

In your room, I'd go for the 16 or the 20 series (with my nod going to the 20 as the first choice). I think you will definitely appreciate the deeper tune of either one for many of today's best DVDs with significant SS content.

**Dr. Spec** · 01-20-2003 03:44 PM

Originally posted by Dr. Spec
If you have email listed, I'll send you my FR sweeps with various phase and tune settings.

Kevin: You don't have email listed. Send me an email and I'll reply with the Exel file.

Ed

**HBombToo** · 01-20-2003 03:48 PM

Originally posted by Dr. Spec

Kevin: You don't have email listed. Send me an email and I'll reply with the Exel file.

Ed

Doc. would you mind sending me the exel file?

hnavaroli@alamosapcs.com

Thanks in advance

HBomb

**Dr. Spec** · 01-20-2003 04:00 PM

Originally posted by HBombToo

Doc. would you mind sending me the exel file?

hnavaroli@alamosapcs.com

Thanks in advance

HBomb

You've got mail!

**HBombToo** · 01-20-2003 04:14 PM

Originally posted by Dr. Spec

You've got mail!

for some reason I can't hit the first link...

www2.markfitzsimmons.com:8000/gomer/

I don't understand?

Thanks
HBomb

**kberg** · 01-20-2003 05:02 PM

Dr. Spec,

Here ya go:

Thanks again!

jbkb@prodigy.net

**Dr. Spec** · 01-20-2003 05:17 PM

http://www2.markfitzsimmons.com:8000/gomer/

Try this Bomber. It should work. I could send the file, but it's too damn large for most email servers to handle, even zipped. It's better to download.

Ed

**goingganzo** · 01-20-2003 10:48 PM

i concer in subs go low or go home. in the new movies like lotr,aotc, spiderman and u571. all have low and loud llfe. i have tuned my new sub to 17 hz. hopefully my subs come soon. my velo will play to 20 hz prety good.

and dock is the man just gives the hook up to all of us. i bet you will get some sort of disc.

**goingganzo** · 01-20-2003 10:49 PM

just ran the test on my comp speakers and they have a lower limit of 43 hz lol

**faster100** · 01-21-2003 01:34 PM

what do you do with the download?? burn to a cd? i am downloading it now... just curious

**Dr. Spec** · 01-21-2003 05:07 PM

Yes, burn it to a CD and run it through your DVD player. Be careful on volume - I burned mine so the 100 Hz tone started first, and I set it to 80 dB at the seat and then let the sweep run from 10 Hz on up after that.

Record your SPL at each frequency, add in the RS Correction Factor, and plot the results vs. the Frequency. This will be the in-room FR of your sub.

I have the Excel file done, if you want I can email it to you and you can just follow my lead on the spreadsheet - hard part's already done.

I've got 4 charts on the spreadsheet:

1) 0 phase 3 ports open
2) 180 phase 3 ports open
3) 0 phase 2 ports open
4) 180 phase 2 ports open

**faster100** · 01-21-2003 05:17 PM

My dang dvd player won't play cdr's... I can borrow a ps2 from my nephew to run it on.... e-mail me the sheet i'f you would...

**goingganzo** · 01-21-2003 11:22 PM

just put in a cd player. this is cool i am burning it as we speek. i will tripple the 100hz to get some lead time and add it to where it is suposto go too.

**Dr. Spec** · 01-22-2003 06:51 AM

Each tone is 10 seconds long - that's the beauty of it - lots of time to set the volume and take a reading and write it down.

Make sure to use the RS Correction Factors for deep bass - it's way off down really low.

**faster100** · 01-22-2003 09:56 AM

so when the 100 hz test tone plays you set what to where??? The volume to 80db first then each tone you just let play and record the reading via spl meter.. i played a few of these on my computer and some are pretty low, will this damage my sub at 80 db or should i lower the volume after the initial tone

**Dr. Spec** · 01-22-2003 02:22 PM

No 80 dB is perfectly safe for your sub. If you are afraid, set the 100 Hz tone to 75 dB instead. Don't touch the volume after that. You are establishing a reference level from your mains (where they are almost exclusively responsible for the 100 Hz tone) and then you will be evaluating not only your deep bass response relative to that, but also evaluating how well the mains transition to the subs.

You will notice from my charts that I had a nasty dip at my 80 Hz filter point with the phase set to 0 degrees. It went away when the phase was set to 180.

It is clear my sub and my mains are out of phase and this can be corrected by setting the sub to 180. But I don't know exactly why.

I suspected one of three things:

1) The Kenwood is sending the LFE signal out of phase with the signal to the mains.

2) The variable phase control on the SVS amp is wired backwards.

3) I wired the mains out of phase with respect to the LFE signal. I used red/+ and black/- so I didn't think the problem lay there. SVS assures me the variable phase control on the Indigo amp is wired correctly. That leqaves the Kenwood as the culprit. SVS says they have seen this on low end receivers before. Truth be told, they said the relationship between the phase of the sub and the phase of the mains is quite complex, and they are not directly related.

Bottom line, running the sweep immediately pointed out the phase problem at the filter point and I was able to easily fix it. Another unforseen benefit of this project.

**Tour2ma** · 01-22-2003 02:47 PM

Doc,

If you don't mind, please e-mail me your spreadsheets as well.

tour2ma@earthlink.net

Thanks...

**Dr. Spec** · 01-22-2003 05:19 PM

You got it - I'll send it later tonight.

Edit: You've got mail!!!!!

**dbournival** · 01-22-2003 08:05 PM

What are the correction factors for the RS SPL meter? When I did my system 1 with the BA PV600, to even it out with the main speakers it had me dial it back 12db. I thought that was too much so I cut it in half. My polks came in at 0 and they sound weak, I just ordered a PSW404 to add to it...

**Dr. Spec** · 01-22-2003 10:27 PM

Originally posted by dbournival
What are the correction factors for the RS SPL meter?

http://members.tripod.com/~terrycthe...um/page11.html

**dbournival** · 01-23-2003 01:34 PM

Thanks Dr.Spec.

So at 25hz is says to add 5, so if my reading is "75db" it is really 80db correct?

**Dr. Spec** · 01-23-2003 04:46 PM

Originally posted by dbournival
Thanks Dr.Spec.

So at 25hz is says to add 5, so if my reading is "75db" it is really 80db correct?

Correct.

**goingganzo** · 01-23-2003 05:07 PM

and at 23 you woulf add 6.25 db? i think just ran a sewwp on my ht i have a dip at 70hz, it is like 66 hz and both adkacent # are 76 this is wierd. and i dont get anything below 20 hz with calibrated to 70 hz at 100 .

**goingganzo** · 01-23-2003 05:22 PM

man i get alot of room gain siting on the rear couch and allmost none siting on the front couch. the rear couch is on a platform and the front is on the tile/carpet concrete floor.

**Tour2ma** · 01-23-2003 05:35 PM

Height factors into standing wave patterns, it's a floor/ ceiling thing.

Probably in a reinforcing zone on the rear couch and a cancelling zone on the front. Often we focus too much on the former, as they tend to be the most annoying, and too little on the latter.

**Dr. Spec** · 01-23-2003 06:26 PM

Originally posted by goingganzo
and at 23 you woulf add 6.25 db? i think just ran a sewwp on my ht i have a dip at 70hz, it is like 66 hz and both adkacent # are 76 this is wierd. and i dont get anything below 20 hz with calibrated to 70 hz at 100 .

Man, keep your units straight! You're confusing me. You are using 70 dB as your reference volume at 100 Hz, right?

So you have a sharp 10 dB dip at 70 Hz and are OK on both sides? Try reversing your phase on the sub. That could be your filter point.

**goingganzo** · 01-23-2003 11:31 PM

i think the filter point is 80 hz i am running thx setup on the recever. i think i am going to get a stand for my mic. i did some more tests they were just random. if i turned the mic just a bit it would gain like 5 db+. my responce from 56-63 has like a 16 db hump and drops fast to 66 at 70 and rebounds at 75 and my sub dident get any readings from 10 to 18. this is all with my velo just want to get some referance levels befor i get my new subs. the bass is good up front but it just gets alot boomey in the rear. i had to drop the celing to conseil a air duct and their is a platform below it. i think there is just more to vibrate there so that is y it is louder.

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