Servo 15

gregure

Ok, I'm a little bit on the edge here. I've been saving up to buy a new sub, and I've had my heart set on the SVS PB2+ for some time. However, I went into an a/v place in San Francisco yesterday, and I was checking out new receivers and speakers. If I go with new speakers, it will be a long way off, but a new receiver and sub are looming within the year. I was looking at Paradigm speakers and the Servo 15 sub is massive. It sounded great, the reviews are amazing, and its frequency response is unreal (down to 10Hz!) Now I know for movies the 16Hz SVS provides would be enough, but for classical music (with organs, bass drums, string bass, etc) I'm thinking the extra Hz from the Servo would be wonderful. Overall I was very impressed with Paradigm speakers, although a complet package for surround is three times the price of a system of Polk Rti's. Now for the questions. Does anyone have any experience with this sub? Does the PB2+ reach that low with confidence? Which one delivers more accurate/tight bass response? I'm thinking Paradigm's other speakers are so fine, why would their sub be any less so? Dr. Spec, I hope you can chime in on this one. Thanks to any who provide feedback. Incidentally, I've decided on the B&K AVR 507 for my new receiver.

steveinaz

I might be mis-quoting, but i think it can be tuned down to 13Hz?

VR3

My SVS PCi 22-31 (25-31, free 22hz tune) - in my room hits down to 15hz with only a 4db drop from 85db at 100hz.

I dont know how large your room is, but with room gain -- the SVS should POUND the low frequencies...

The PB2+ can be tuned from 25 - 20 - 16

gatemplin

Paradigm makes very solid subs. The Servo15 sounds very accurate and musical IMO. I was considering the PW2200 or Servo15 before I decided to make my own. You should also take a listen to the Paradigm Seismic 12 and just for fun the Signature Servo (haven't heard it yet). Are you looking at the Paradigm Reference series?

gregure

Yes, I'm looking at the Reference Studio series. I don't have experience with SVS (they really should allow for demos at some places), but that Servo 15 was very good. I'm beginning to lean that way...

gregure

Correction: The Servo 15 is in the Signature series, only Paradigm suggests it accompany the Studio series as well.

gatemplin

The Servo15 is considered part of the Studio series, the Signature series has it's own sub the Signature Servo.

disneyjoe7

I own it, I LOVE IT

Dr. Spec

The Servo-15 is a GREAT subwoofer. Most people who have heard both lines rank it with the 20-39PC+.

The PB2+ will easily better the Servo-15 in terms of clean output, and match its extension capabilities when tuned to 20 Hz.

Remember, the tune point is not the minimum frequency a ported sub can play. With quality woofers and careful blending of custom EQ and high pass filters, SVS extracts about 1/6 octave of extension below each tune point.

In my 2000 ft3 room, the PB2+ and the PB2-Ultra in the 20 Hz tune will dig strong to 14-15 Hz. Since the lowest note a 32' pipe organ can play is 16-17 Hz, the 20 Hz tune is fine for all natural music and DVDs.

Doc

gregure

Thanks Dr. Spec. I knew you'd have something interesting to say. I realized the limit was lower than the tune point, but I think I had the Signature Servo limit in my head, which is 11Hz. Didn't know about the pipe organ extension, so that is something interesting to know. Thanks, I guess I'm back on the path to the PB2+. Also, a quick question: In your output graph, it looks like the 16Hz tune is the loudest at lower Hz levels, which is what they say is the case, but it also looks to be the same volume at the higher levels as the other tunes. I thought the 16Hz tune was supposed to lessen the volume at more common bass levels. I always planned on checking out the 20Hz tune for movies. Would you recommend the 16hz tune for classical music? Thanks.

Dr. Spec

Take a close look at the description of the 16 Hz tune. The sub level is bumped 4 dB to compensate for the sensitivity loss when 2 ports are plugged. And truth be told, it might even be closer to 5 dB.

Go to the SVS website (or my PB2-Ultra review at HTF) and take a look at the uncorrected curves for the 20 Hz and 16 Hz tunes - you'll see the loss in efficiency as each port is plugged.

The "problem" with the 16 Hz tune is that you've bumped the sub level 4-5 dB higher than the 25 Hz calibration point just to maintain parity. The woofers and amp are working that much harder to provide the same SPL level as the 25 Hz tune. That leaves correspondingly less dynamic headroom for peaks.

The PB2+ enclosures were not really designed to operate optimally in the 16 Hz tune. The capability is there, but the native tune is 25 Hz and these subs operate the best in the 25 Hz or 20 Hz tunes.

Still, as you can see the 20 Hz tune curve returns to baseline at 15 Hz in my room, and is probably -3 dB @ 14 Hz. That is ridiculously deep extension while still retaining two huge 4" wide flared ports for good air flow and minimum port noise.

There really is very little practical need to run a sub in the 16 Hz tune for music or DVDs. The 16 Hz tune really comes alive in the 12-16 Hz region, and there is simply nothing down that deep in 99% of all program material.

gregure

Thanks Doc, your info is always appreciated. I did read your Ultra review (very impressive), and I saw that the dB level for the 16Hz tune was lower at higher Hz in that review, which is why I was surprised to see such uniformity in the graph you displayed on this thread. Thanks for setting me straight. Can't wait to test it out. 6 months seems awfully far away.

Dr. Spec

and I saw that the dB level for the 16Hz tune was lower at higher Hz in that review, which is why I was surprised to see such uniformity in the graph you displayed on this thread.

The PB2-Ultra review contains both graphs. The first chart shows the straight FR curve in each state of tune, with no change in calibration level. The second chart is what I showed above; with the sub level bumped 2 dB for the 20 Hz tune, and 4 dB for the 16 Hz tune.

Above the tune points though, the sub will throw down nearly identical FR curves if the calibration level is adjusted each time a port is plugged. As you might expect from the above chart, the sub sounds very similar above 30 Hz in all three tunes.

Bumping the sub level when you plug a port is the correct method to maintain parity with the 25 Hz calibration level. It DOES chew up available headroom though, and also requires greater woofer excursion in the lower octaves because the woofers must shoulder the entire output load all the way down to about 18 Hz before the port starts contributing output.

The combination of reduced headroom and extra cone excursion makes the 16 Hz tune a good choice only in moderate size rooms at well under Reference Level playback. It actually behaves much like a sealed sub in the 16 Hz tune over nearly all of its operating range.

Aside from the output limitations, it's otherwise hard to argue against the 16 Hz tune; how many subs stay above baseline all the way to 12 Hz? :cool:

My personal preference for DVD is the 20 Hz tune; it's the best combination of extension and awesome power.

The 25 Hz tune will flat-out crack plaster and STILL digs to 20 Hz in most rooms. If you want to rearrange your hairstyle, knock small items off shelves, and blur your TV screen (I'm serious), the 25 Hz tune is IT. You won't find its clean limits, even if you just get stupid it just keeps playing louder. In fact, if you look at the dynamic compression curves for the PB2-Ultra in the 25 Hz tune (2 meters outside), and add 12-15 dB for boundary effects and room gain, it won't begin to compress in-room until over 130 dB at 2 meters. THAT'S HEADROOM. :cool: