20-39 PCi vs PC plus

shiu

I am planning on adding a 20-39 PCi or plus to my PSW404. Just 2 questions:

1. Is the tunable port and more power worth the extra $226 to get the plus.

2. What will be the best way to use the 404 to supplement the SVS.

Thanks.

Dr. Spec

With the Plus line, you get:

- a much more capable woofer, the dB-12
- a 525 watt amp
- triple flared ports with variable tuning
- a CV 0-180 phase control
- custom EQ curves and infrasonic filters at each tune point

Easily worth $225 extra IMO. The Plus line of subs rocks.

You won't need the 404 with a Plus sub. I'd move it to a different rig in the house.

racer4551

I definately echo Dr.specs thoughts on not needing the other sub,i purchased a 20-39pc+ and had paradigm pw2200 and did not need the paradigm at all in my setup, the svs more than covers all your low end needs!It basically drowned out the paradigm sub which is a very fine sub in its own right.

kberg

shiu, I had the same type of question when I was debating between the two SV subs, but Doc and others quickly convinced me to go with the plus. Now I wasn't able to do a side by side comparison between the two, but I honestly believe, just from the stats alone, that it really is worth the extra coin. And it may seem like a big difference in change now, but it won't shortly after you get it (I was convinced of that, too!).

gacole2000

Money well spent, and you won't be wondering 'what if'. Save a little while longer and go with the plus.

Greg

shiu

Thank you all for your help!
Dr. Spec, my room size is 11'WX18'LX8'H. If I plug the port of the 20-39 PC-Plus to get it down to 16 Hz, would I still have enough output for frequencies above 16 Hz? If not, could I just adjust the subwoofer speaker level in my Sony DA4ES, or use my 404 to make up for it. I assume if I compensate for it by adjusting up the speaker level I would lose some head room, right?

Dr. Spec

There is no need to plug a port on the 20-39PC+ for 99+% of all music. In the stock tune, it will dig to about 17 Hz in that room before trailing off.

If you plug a port, expect extension to 12-13 Hz in that size room. You'll never notice a difference in the two tunes in nearly all circumstances.

I never ran my 20-39PC+ with any port plugs. It really does troll deeper than sin in the stock tune.

If you do plug a port, the sub will still have plenty of output, but you will lose about 1.5 dB of volume above the tune point, which can be compensated for with the sub level control on the AVR.

In either case, you will not need another sub for "help". The big black tower of power will completely alter your perceptions of bass power, clarity, and extension. There is a whole world of bass below 30 Hz you haven't yet heard properly reproduced.

shiu

Dr Spec, two more questions and I'll be able to make my final decision.

1) In my room, the PSW404 has a boom (8 to 10 dB) at around 60 hz. You mentioned the 20-39 PC Plus has custom EQ curves. I assume the SVS will display similar characteristics, perhaps at a different frequency. Will these curves allow me to eliminate/reduce such boom.

2) The transformer of the PSW404 hums a little loud, I can hear it from my listening position when the room is totally quiet, like 5:00 a.m. in the morning. I have Polk replaced the power supply once, same hum remains. The Polk service representative told me the hum is normal. Will the much larger power supply of the SVS hum even louder?

By the way, I thought you own an Ultra, it sounds like you own a 20-39 as well. Do you find its sound quality similar to the Ultra, I mean for frequencies above 20 Hz. Regardless of your answer to this one, there is no way I can afford the Ultra. I am just curious to know how much gain you get for that much more money.

Thanks again for being so helpful.

Dr. Spec

Each tune point is a combination of the port configuration, and the tune switch setting.

For the 20-39PC+, the stock tune is 3 ports open with the switch set to 20 Hz. If you want to tune the sub to 16 Hz, you plug a port and change the switch setting to 16 Hz.

Each switch setting has a custom EQ curve and an infrasonic filter, both designed to work with that associated port setting. The EQ and the infrasonic filter curves are non-user adjustable.

Your 404 may exhibit a 60 Hz peak due to room acoustics more than anything else. To knock down a peak, you need to work with sub placement, the phase control, and sometimes you even need a parametric equalizer (which is what you might have been thinking of).

The only SV subs with built-in PEQs are the PB1+, the PC-Ultra, and the PB2-Ultra. The SVS PEQs are single band, cut only units. They (like any other single band PEQ) have three controls: bandwidth, frequency, and dB cut.

None of the amps on my SVS' have ever noticeably hummed at the normal gain settings when they are sitting in Standby mode.

I have owned three SVS': a 20-39PC+ (now owned by gacole2000), a PB2+ (sold locally), and now a PB2-Ultra. I've also been living with a PB1-ISD for about two months.

While the Ultra driver (TV-12) has a sound of its own, the difference over the Plus driver (dB-12) is subtle, not huge. The best performance values in the SVS line-up are the Plus models, IMO. The Plus cylinders are simply outstanding performers - you will be amazed at the difference one makes in your system.

shiu

I am going to resist the temptation of ordering the PCi now. Instead I am going to save up for another month and go for the 20-39 PC+. Thanks again for your help. I think Dr. Spec should get an honorary PH.D degree in AV technology.

Dr. Spec

Originally posted by shiu
Thanks again for your help. I think Dr. Spec should get an honorary PH.D degree in AV technology.

You're welcome, but I wouldn't go that far. I know enough to get by, but put me in a room with the head designers from some of these big companies, and I'm listening and taking mental notes, not talking.

shiu

It will be another 5 weeks before I am ready to order a SVS. In the mean time I wonder if there is something to gain by playing with my bass management settings. My current settings are as follow:

Front l/R RTi38 - set to small, 80 Hz
Center CSi30 - set to small, 80 Hz
Surround L/R & Surround back L/R RM2350) - set to small, 120 Hz
Subwoofer PSW404 - set to 120 Hz
The 404 has a 8 dB boom at 60 Hz on its own.

The -3 dB limits of the speakers are:

RTi38 - 49 Hz
CSi30 - 55 Hz
RM2350 - 130 Hz
PSW404 - 32 Hz

The RM2350 are satellites. I don't understand enough about how bass management works, but my goal is to achieve accurate sound reproduction. Could I make some improvements with different settings?

Dr. Spec

Use the LFE (Unfiltered) input on the 404. If you use that, the low pass filter on the 404 is bypassed. This is appropriate since you are filtering at the AVR and not the sub.

Experiment with the phase control and placement with the 404. You might be able to knock out that 60 Hz peak and it might sound less boomy after that.

Other than that, everything looks OK to me.

kberg

Originally posted by shiu
I am going to resist the temptation of ordering the PCi now. Instead I am going to save up for another month and go for the 20-39 PC+.

"You chose.....wisely." - Grail Knight (Indiana Jones and the Last Crusade)

shiu

I am using the LFE unfiltered input. I tried moving the 404 around but I don't have the option to move it more than 6" in any direction from where it is. I will try the phase control thing but it is a toggle switch so I can select either 0 or 180 deg but not in between. As soon as I get that SVS sub I will try to sell the 404.

shiu

I thought I had decided on the 20-39 PC+. Now I know I cannot get rid of the 60 hz peak due to my room response (Yes Dr. Spec I did try both 0 & 180 deg), I really would like to get the PEQ. As such, my choices are the PC ultra, CS ultra, and the PB1 or 2+.

It seems that the PB2+ offers the best deal, but it is huge. I do not understand how SVS can put in one additional driver for only $100 more.

I like the CS ultra because it comes with an external amp but I am not sure if the CS ultra/ext amp combo offers the PEQ. Am I right in assuming that the PEQ will solve my 60 hz peak problem? And could someone please tell me if the CS ultra offers the PEQ feature?

Thanks

Dr. Spec

The following SVS models offer the PEQ feature:

PC-Ultra
PB2-Ultra
PB1-Plus

I would not even consider a passive version of the Ultra since the on-board amp offers so many features:

1) CV phase control
2) Single band PEQ
3) Custom EQ curve and infrasonic filter at each tune switch setting.

The TV-12 Ultra driver is extremely expensive ($600), as compared to the dB-12 Plus driver ($300). That is the difference in price between the Plus and Ultra models. Also, the wood finish clearly adds cost to the PB1-Plus.

If you need a PEQ, you can always buy an outboard unit with several bands (like the Behringer Feedback Destroyer for $120) rather than opting for the more expensive SVS simply because it offers a single band PEQ.

In other words, the 20-39PC+ and the BFD, will cost less than the PC-Ultra.

shiu

Originally posted by Dr. Spec

I would even consider a passive version of the Ultra since the on-board amp offers so many features:

1) CV phase control
2) Single band PEQ
3) Custom EQ curve and infrasonic filter at each tune switch setting.

Did you mean "I would not consider..........................."
It seems that you prefer the "on board" amp of the PC Ultra.
Do you think the PC Ultra's single band PEQ would help eliminate my room response problem?

Thanks again.

Dr. Spec

Sorry - posted edited and you are correct - I was typing too fast.

I much prefer the powered models over the passive. They are really becoming an integral part of the overall performance spectrum of the sub. The BASH amps are packed with features and custom tailored to each model subwoofer.

Yes, the PEQ on the PC-Ultra will knock out a single peak in a room. The CV phase control might help too, but the PEQ is almost a sure thing - it has 12 dB of cut and variable bandwidth and frequency.

Again, the PEQ is nice, but don't feel like you "have" to buy a more expensive SVS to get one. You can always buy an outboard PEQ for about $120 (the BFD).

Of course the best PEQs can get very expensive, but the BFD seems to work very well for many enthusiasts with difficult room acoustics.

If you want the PC-Ultra for other reasons (like the awesome driver), be my guest and buy it; I'm sure it will be awesome. I just didn't want to appear to be "overselling" you on a higher model than you need simply for the PEQ feature alone.

shiu

My PSW404's room response is as follow

HZ dB
100 81
90 81
80 80
70 82
60 90
50 82
40 74
30 67

Based on your reply, the PC Ultra's single band PEQ should be able to take care of the "single" peak. I assume the PC Ultra may peak at a different frequency.
Since my room is not that big (11WX18LX8H), the PB2+ will be an over kill. I am considering the Ultra because I am concerned about how much bass output a single 12" driver can produce. For example, with a pair of RTi10, you get 4 X 7" subwoofer drivers, the combined surface area is much greater than that of a single 12" driver. With the Ultra, at least I know I am getting the most that one can expect from a single SVS driver, right?

shiu

Dr., something came to mind, the PC+ or Ultra has a FR of 20 to 100. That will blend with my front channels RTi38 and the Center channel CSi30, but what can I do with my tiny RM2350 surrounds?

Would you still say I don't need to make use of the PSW404, perhaps just to fill the holes for the surrounds??

Dr. Spec

Yes, the Ultra will have a completely different in room response curve.

It will probably peak at around 22 Hz and then get back top baseline somewhere around 18 Hz.

The ability of a woofer to move air is not a function of surface area alone. The linear excursion of that driver is >26 mm, and the Vd (displaced volume) is about 2.6 liters. The TV-12 in a large, highly efficient, properly tuned and vented enclosure can move a huge amount of air. Trust me, output will not be a concern in that size room.

Regarding your surrounds, I would set all the speakers to small with a 100 Hz crossover and upgrade your surrounds to larger speakers at your convenience. When you do, drop your xo to 80 Hz.

shiu

Thanks to the Dr. (PHD in "Subwooferlogy") I think I now understand that even the PC+ could move enough air in my room. That would (not necessarily that it could) mean that the PC Ultra would do it in a more leisurely fashion. I was seriously considering the CS Ultra, but now that I understand more about the pros and cons of both, my final choice is the PC Ultra. I will order it in a week or two.

Thank you all,

Shiu

PS I may be back for more help in a few weeks.........

Dr. Spec

You're very welcome. It's a fine choice (obviously). The best cylinder SVS offers. I'll be glad to help you dial it in whenever you are ready.

I just finished (finally) dialing in my PB2-Ultra, and I used the CV phase, the low pass filter, and the PEQ to obtain a very flat curve from 100-30 Hz. Below 35 Hz, the curve rises gently due to room gain, but I'll take free bass anytime below 35 Hz. :-)

All controls worked as advertised and the combination of all three is a very powerful tuning tool.

Here is a screen shot from my test rig. The SPL shown is actual - try 110 dB at 12 Hz in the 16 Hz tune. This sub is ridiculously powerful. I prefer the 20 hz tune for DVD HT, and the 25 Hz tune for music.

Doc

monkeyphant

I prefer the 20 hz tune for DVD HT, and the 25 Hz tune for music.

Doc:

What is your AVR sub level setting for DVD HT and Music? What is the plate gain setting on the ULTRA? When you switch between HT and Music, do you change the AVR sub level?

MP

Dr. Spec

That question is more complicated than you think because for music, I'm using the 2900 and external outputs so there are actually 3 sub level gain stages to toy with for music: the 2900, the External Sub In Level in the 3803, and the regular sub level in the 3803 in the external input mode.

Short answer - the gain level never changes at the sub.

For HT, I bump the sub level 2 dB from -7 to -5 when I plug port.

For music, I unplug the port, set the switch to 25 Hz, and switch the AVR to external inputs. The sub level is precalibrated for that setting, and the DD/DTS sub level has no bearing on it.

monkeyphant

For HT, I bump the sub level 2 dB from -7 to -5 when I plug port.

How does this correlate with your PB2-ULTRA FR Sweep Graph?

MP

Dr. Spec

The graph shown above is -7 for 25 Hz, -5 for 20 Hz, and -3 for 16 Hz.

In all, a 4 dB gain for the 16 hz tune to keep things even with the 25 Hz level down to 22 Hz or so.

The deeper tunes just troll, don't they? :cool: I played Revolutions in the 16 Hz tune at -3RL and some of the infrasonics were just frightening.

monkeyphant

The graph below is -7 for 25 Hz, -5 for 20 Hz, and -4 for 16 Hz at -20RL.

monkeyphant

Here is the graph:

Dr. Spec

All PB2's will react about the same at each tune point.

Considering we are using entirely different test methods in different rooms, the curves are strikingly similar, really.

I'd say you're generating some fairly accurate data.

Since you are using 3" ports, your efficiency in the 16 Hz tune might drop even a bit more, and possibly you would need a 5 dB (total) boost over the 25 Hz tune to get things to totally even out.

Regardless, if I know the DVD has true infrasonics, I'll use the 20 Hz tune and call it a day. It's extremely rare to get strong content at 10-12 Hz, but it does happen; Revolutions is a good recent example.