20-39 PCi vs PC plus

shiu

Doc, I downloaded the tones from Paul's link. These tones are much louder. I have to turn my receiver volume to -33 in order to get the same level that I got with the sweep tones on the test DVD. I am still not sure if my PCU volume is set too low. I used the same downloaded tones on the RTi38 mains, with sub set to "no". With volume set at -33, I was getting 5 to 7 to 25 dB louder within the range of 25 to 100 Hz (25 dB higher at 100 Hz). My mains and surrounds are all calibrated to the same level, using either the reciever's test tones or the test DVD. Either way I got around 73 to 75 dB with receiver volume set at -26.

I am really wondering if I have the PCU volume set too low. It sounds great in H.T. movies but it does sound weak in music. Is there a simple test I can do?

Dr. Spec

Please explain your speaker set-up and bass management set-up, and make sure you addressed all points I made in that earlier post about checking for set-up errors.

ken brydson

God I'm glad I'm not a tweeker. I just plugged my new 25-31PC+ in, turned it on and it's blowing my socks off.
Hope you can get yours to where you want it

shiu

Doc,

After I read your previous post, I reset the DA4ES to factory default condition, then I set things up again as follow:

1. All speakers set to small.
2. Mains RTI38 XO set to 80 Hz.
3. Center CSI30 XO set to 100 Hz.
4. Surround RM2350 set to 100 Hz.
5. Surround back RM2350 set to 100 Hz.
6. All speaker levels set to obtain 75 dB from listening position.
7. Sub level to -10 in the pre/pro. The available range is -20/+10.
8. DVD player set to bitstream. No problem playing DTS6.1.
9. All dynamic range/compression control circuits are "off".
10. There are no bass limiters in the pre/pro.
11. There are no LFE channel level, but there is a LFE mix level, I left it in the default setting of "0", that is the maximum.
12. Low pass filter disabled at the PCU.
13. All ports open, tune switch to 20 Hz.

Doc, so far your predictions have come true, I am getting that "huge" room gain at the low end, and the PCU is going all the way down below 16 Hz in stock configuration. The plug is still in the seal plastic bag. My main concerns are:

a) My mains are about 6 dB louder than the sub between say 30 to 70 Hz, at the same receiver volume setting and playing the same down loaded test tones, yet all speakers would register 75 dB at my listening position with either the internal test tones or those from the DVD test disc. The only sub test tone the DVD test disc has is the LF sweep so I set the sub volume to register the same 75 dB using those tones. The sweep is actually quite slow. It took a long tome to sweep from 120 to 20 Hz.

b) When I played the down loaded test tones through both the mains and the PCU sub, I noticed a dip at around the 50 Hz point, obviously due to some cancellation. I dare not adjust the phase knob because it is in the best position now when the sub is on its own. So looks like there is no way to avoid this cancellation.

c) When I played the THX test tones that come with the Star War DVD, each of the 7 speakers registered 73 dB, only 2 dB lowered than what I got with the test DVD, but the PCU sub only registered 61 dB. The THX test tone does seem to have a much lower frequency signal for the sub, that is the main reason why I think my sub volume is set too low. The PCU gain knob is turned only 1 notch above its minimum position.

I hope you now have enough info to help me. Thanks,

Shiu

Dr. Spec

What calibration DVD are you using? Is it the older Video Essentials, the new DVE, Avia, or S&V?

Everything seems set up perfectly, but you are having sub level calibration problems. Could be the calibration DVD.

On your internal AVR test tones, when the speakers read 75 dB, what does the sub read?

Don't worry about the calibration DVD for now. Start with the AVR test tones first, and adjust the sub plate amp so the meter reads 75-77 dB on C-weighted Slow. Then tell me how it sounds on music and movies.

gatemplin

Originally posted by Dr. Spec
Could be the calibration DVD.

he uses a disc called "Home Theatre Optimizer", never heard of it.

Shiu,
From what I understand the THX tones are just there to make sure you have the right wires connected to the right speakers, not for setting levels. I think it says that on the screen.

shiu

The calibration DVD is "Home Theatre Optimizer" by allsop (website www.allsop.com). I bought it from RS, together with the SPL meter.

Using the receiver's test tones, I am getting 75 dB for all 7 speakers, with the volume set at -26, but I only get 61 dB from the sub. I thought it was because the frequency of the receiver's tone was too high for the sub. If I crank up the sub to get 75 dB, I know the bass will be much louder. Do you really want me to try that? I hope the PCU can take it without bottoming out. It is 11:18 pm right now so I will try it tomorrow.

shiu

Morning Doc:

I set my sub gain to the 2.5 mark, now I get 71 dB from the AVR test tone when the other speakers are getting 75 dB. Listening to the Telarc 1812 I am getting 75 to 77 dB from the background during the last part without the cannon fires. When the cannon fires it peaks to between 85 & 87 dB (looking at the LCD display. I can tell it was doing that 1 sec averaging, I wish I had the analog one). I would be willing to bet that the instantaneous level would have been closer to 100 dB. This is my normal listening level (master volume at -33)for classical music. The difference now is that my couch is starting to complain about those cannons. I watch Diana Krall in Paris again and I am definitely getting the bass that I need for my taste. I am not sure if I want more.

I am going to watch X men and Star War again before I crank it up all the way to 75 dB. You are sure the PCU can take on X men right? These things are way too big and heavy to ship back to the States you know!

Dr. Spec

Jack it up to 75 dB, Shiu! The PC-Ultra can take it and more. Sounds like it was your calibration DVD. Until you get another one (like Avia), use 75 dB with the AVR test tones.

Your AVR "should" be able to remember different sub level settings for stereo CD vs. DD/DTS, so you can optimize HT and music settings for the subwoofer.

No, you won't break the sub. Trust me, in that size room, you can easily hit 113-115 dB at the seat without straining the sub. It's not even working hard at 100 dB bass peaks. If you are still a little tentative, don't be afraid at all to "at least" look for 105-108 dB bass peaks (c-weighted fast) at the seat for HT.

And the design is totally modular - if any part ever breaks, SVS will ship you a new part, and it can be swapped out literally in minutes.

If would take a seriously deranged mind (like Sid's dad) in a really huge room, to damage a PC-Ultra, and even then the user would have to consistently ignore the warning signs that the sub is being overdriven. The TV-12 is a VERY rugged driver, and SVS can count on one hand the number of field failures at the hands of even the most abusive of customers.

Have fun and work up a little courage!

shiu

WOW! my R.E. just got an unexpected massage! It hit 108 dB on the first explosion scene in Attack of the clones. DOC, you're right, the PCU shows no sign of bottoming out at all.

I still want to buy a good calibration DVD, is AVIA the way to go?

gatemplin, I understand what you're saying, but so far I found the THX audio test included in the DVD movies quite consistent with my AVR's internal test tone. They seem to give a couple of dB lower across the board.

I think I am going to stop tweaking for a while and do some serious listening.

Thank you everyone again for all your help,

Shiu

Dr. Spec

Glad you are loving it.

You are in the ball park now with sub level calibration and getting some pretty serious power and SPL with 108 dB bass peaks (as read on the meter).

Since the meter is c-weighted, the actual SPL on the AOTC ship explosion would be about 111 dB since that passage is largely centered in the 30 Hz region.

I agree, sit back and listen and feel and fine tune the sub level for music and HT - you'll arrive at preferred settings over time for each.

gatemplin

Glad you like what you are hearing now. I havent heard anything bad about the Avia disc. A simpler, cheaper alternative is the sound and vision disc.

rlam01

Three nubie questions:

1. On my PSW303, what is the phase switch for?

2. What tools are needed for analysis of one's system (like the pic posted by Dr. Spec)?

3. Why are there amp binding posts on my sub?

Thanks all.

Dr. Spec

Three nubie questions:

1. On my PSW303, what is the phase switch for?

2. What tools are needed for analysis of one's system (like the pic posted by Dr. Spec)?

3. Why are there amp binding posts on my sub?

Thanks all.

1) It reverses the polarity on the subwoofer. It can be useful if the sub is not placed on the same wall as the mains. Whichever setting provides the best bass should be used. Often the difference between the two settings will be inaudible. Phase refers to the timing of the signal to the subwoofer in relation to the other speakers. If the phase is incorrectly set, the sub will compete with the other speakers rather than compliment them. Some of the better sub on the market have variable phase instead of a 0/180 switch, and this is even more flexible, and allows fine tuning of the phase control.

2)

measurement mic
mic preamp for phantom power
professional calibration of both above
software (several programs out there)
sound level calibrator
connectors and cabling
a steep learning curve
about $800 for above gear
a powerful PC

3) For a high level (speaker level) connection. You can send the subwoofer a signal from the L/R mains speaker outputs, and then select the frequency you want to crossover to the sub. From the sub, you run back to your main speakers. It's messy and has several downsides compared to digital bass management with the sub cable. Very few people use high level sub connections these days.

Doc

weavercr

Dr Spec, what are the inside diameters of the 3 ports in the SVS? Are the ports different lengths?

Dr. Spec

The SVS Plus and Ultra cylinders use three 3" I.D. wide-flared ports (on btoh ends). So does the PB1-Plus and the PB2-ISD.

Depending on the model, the vent length does differ. Shortest on the 25 series, and longest on the 16 series, etc.

But all three vents are all the same length in a given sub.

up2youjoe

Dr. Spec,

My PB2-ISD shipped today. What will I need (software/tones)to plot a curve?

Thanks in advance as I'm sure there will be more questions

Dr. Spec

RS meter
http://beyond_gomer.tripod.com/ - test tones
spread sheet - see pdjami for a version with RS correction factors

up2youjoe

Dr. Spec,

I have the meter

I emailed Paul for the spreadsheet earlier and that website for the tones doesn't seem to work. Can I get them somewhere else?


Thanks

gatemplin

You can also get a spreadsheet and test tones from http://www.snapbug.ws/bfd.htm

Dr. Spec

Sometimes that website is down. Try again later, or try the snapbug sites.

shiu

I just realized I forgot to post the latest F.R. of my PCU. I also plotted the F.R. of the PCU with a) the RTI38 mains on, and b) with the Energy reference 22 Connoisseur on. With the Energy, the F.R. was within +/-3dB from 18 to 100 Hz, but with the RTI38, there were significant dips between 47 & 90 Hz. The RTI38 sits right on top of the Energy so they are virtually in the same location. I tried adjusting the phase but there was no way I could eliminate those dips. I was not going to spend too much time on it because I will be buying a new pair of mains soon, hopefully next week. The RTI38 will go to the L/R surround positions. I guess once I get the new main speakers, I will have to re-calibrate the PCU again. This is dreadful!

Dr. Spec

That is a fabulous looking "house curve". You must have been researching the topic of house curves with Wayne over at HTF!

The PEQ "Q" only ranges from 0.1 to 0.9 - is the 2.1 a typo?

I can't imagine the PC-Ultra not sounding good with that curve? How are you liking it after several weeks of ownership and getting used to what it can do for music/movies?

up2youjoe

Dr. Spec,

How does this curve look for my PB2? I got the tones from Pjdami. The phase is et to about 60 and the gain on the SVS is set to about 10 oclock. I have one port plugged.

VR3

killer curve

pjdami

up2youjoe,

Looks like you got some more predictable results this time with those test tones / spreadsheet compared to what you got on your thread with the PSW505 with the other tones. Anything that you can explain?

Looks like a good curve. Plenty of room gain there. Doc always says that gain below 30 hz is good. The 30 - 40 hz bump you may want to tame a bit by moving the sub out a few inches from the corner one way or the other and see if it tones it down some.

20 hz tune looks good there. The 25 hz tune in the same position will exaggerate the hump more (at least that was my experience).

Your sub may be just a smiggin too "hot" in the calibration as well judging by the consistent +5 db you are getting between 45 - 75 hz. Just a hunch here. Looks like you started off at 85 db @ 100 hz.

Dr. Spec

Try messing with the phase a bit more to minimize those irregularities from 60-100 Hz. Otherwise really decent curve with extension right to 20 Hz - awesome.

Play ROTK where Frodo's heart is beating at the end - killer 20 Hz and below content in that scene. You'll know it when the ports start moving some air.

shiu

Doc, actually I stopped playing with it since May 22, I just forgot to post the latest version. By Q=2.1, I meant 2.1 divisions, so you're right it is really 0.21. I'll edit it tonight.

I do enjoy the PCU's clean bass, for a while I have to get use to the fact that I no longer hear the kind of "bass" that I used to hear from the PSW404 all the time. The PCU produces more defined low frequencies, obviously without exaggerating it.

up2youjoe

Dr. Spec,

With the crossover on the receiver set at 80hz, I assume the SVS won't get to play anything above 80hz. Correct? Also, Would I gain anything by plugging the second port? I am sure I would still have plenty of headroom.

Thanks,

Steve

gatemplin

You will still get output above 80 Hz from the SVS but it will slope off at probably 12 dB/octave. Plugging a second port will get you a lower tune and more extension at the sacrifice of output higher up. Try both and see how you like it.