Why no “slam” from my dual PB13 Ultras? - Page 3 - AVS Forum | Home Theater Discussions And Reviews
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post #61 of 129 Old 02-13-2015, 08:25 AM
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Quote:
Originally Posted by Alan P View Post
When running sweeps with the main speakers it should be subs+FL -OR- subs+FR, never with subs+FL+FR.
Alan, I had not heard this before. Why not with both front left & right?

Thanks!
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post #62 of 129 Old 02-13-2015, 08:39 AM
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The subs look to be setup correctly. The fact he has measuring gear, and an SPL meter is reading into the 120dB range means he's playing those SVS PB13's for all their worth. In my old 3000-3500 cubic foot basement - I could only get my pair of PB13 Ultras to play in the 115dB range cleanly - even co-located in the corner.

I wasn't fully satisfied with that. For my demo moments I like running at reference with the subs about 6dB hot --- and that isn't enough output to get there.

My former JTR Captivators (pictured in the sleeping bag video linked previously) solved that issue --- a pair, underpowered like that in the video was capable of about ~125dB levels in the same room that my pair of SVS PB13 Ultas could produce. That A/B done with a radio shack meter - and for the test I loaded both SVS in a corner stacked so I could get the co-located +6dB SPL. The JTR were placed on either side of my projector screen and getting less room gain. The JTR pair properly powered by my former Crown XLS-5000 amp could reach into the low 130dB range happily!

From the moment I heard a single JTR Captivator in the 2011 subwoofer meet I knew it was far superior to my pair of SVS PB13 Ultras. There's more history than that - that I've written before - but that is summarily the answer. For some of the bass heads around here, used to car audio bass levels (myself included) --- 2 PB13 Ultras isn't enough. For others a pair of SVS PB13 Ultras is vast overkill and they can't understand why anyone would want more. I now have eight 18" sealed in my room, and it's ~15% to 20% better than a pair of JTR ported Captivators.

I don't agree that basements give up any SPL over a wooden floor --- in fact basements in general probably give extra boundary gain resulting in additional SPL --- but you give up a LOT of that shake factor and feel that may be a big part of what you feel you are missing.

I strongly recommend you take a look at the JTR product line. A pair of JTR ported Captivators, or a Pair of JTR Orbit Shifters. They are a top shelf subwoofer offering for someone like the OP. Otherwise --- you are looking at pursuing the DIY path to get what you seek.
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post #63 of 129 Old 02-13-2015, 08:55 AM
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^^^

Can't run sweeps with LCR Red.

What we need is a sweep with subs+CC and one with subs+FL or FR.

Also, he needs to get his trim up not down.
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post #64 of 129 Old 02-13-2015, 09:02 AM
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Quote:
Originally Posted by smcmillan2 View Post
Alan, I had not heard this before. Why not with both front left & right?

Thanks!
I shouldn't have said "never", it's just when trying to get the splice between mains and subs right it's best to do one speaker at a time. Also, I don't know why, all I know is that's how it's described in the guide.
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post #65 of 129 Old 02-13-2015, 09:04 AM
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That really looks like a wrong setup/placement issue. Those subs should give you a ride for your money...

Flat frequency response doesn't automatically means good sound. I would do a sub crawl and find the best and second best spots for the subs and then let Audyssey blend them in.

I would also lower your subs gain until you reach 75dB instead of 78dB.

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post #66 of 129 Old 02-13-2015, 09:24 AM
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Quote:
Originally Posted by Alan P View Post
^^^

Can't run sweeps with LCR Red.

What we need is a sweep with subs+CC and one with subs+FL or FR.

Also, he needs to get his trim up not down.
I wasn't meaning at the same time. Sorry. And thats what I meant by the trim. I guess I meant down as in closer to zero, which in a negative number is positive. I think I need another cup of coffee........


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post #67 of 129 Old 02-13-2015, 09:26 AM
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We used to live in an apartment long ago with my first home theater. The room was long and narrow. (I am guessing 12' x 18') We were configured along the narrow. When I switched the set up so we were watching the along the long axis, the results were astounding.
I might suggest turning your configuration 90 deg. if possible. Room layout has a huge effect on sonics. Sometimes this is just not possible, I understand.
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post #68 of 129 Old 02-13-2015, 09:46 AM
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^^^

No need to swap the room around, you can test it by just moving the subs and sitting in the "temp" MLP.
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post #69 of 129 Old 02-13-2015, 10:22 AM
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In the midbass slam thread it was agreed upon by many that it was upper bass like 60hz-150hz. That resonates in chest cavity.
And you need high SPL of over 100dB to feel it.

We experience this in great venues and crave it at home.

Obviously that frequency range involves the sub and the mains.

Most people have a SBIR hump and dip. Try positioning front speakers closer or farther from front wall.

I wonder what the frequency response would look like when played at 100dB?
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post #70 of 129 Old 02-13-2015, 10:52 AM
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Zorax2,

The poster who suggested that you also take a look at how your front stage is being powered is right.

Page 28 of your X4000 PDF "Use speakers with an impedance of 6 – 16 Ω/ohms."

Page 8 of your KEFs "
Remember it is easier to damage the loudspeaker by using a small amplifier driven into
distortion by too much volume, possibly with bass and treble boost, than by using a larger
amplifier which has power in reserve"


Minimum impedance from the KEF spec sheet: 3.2 Ohms




There are not a lot of receivers that are spec for all channels driven. Your L & R compliment your Sub. I'm not sure what's happening with your Sub, I would start with the basics. Get a tape measure, paper, pencil, and your SLP meter. Turn off Audyssey. The sub crawl might find the best spot in the room, but that spot might not be convenient. I believe someone posted a link earlier for using multiple subs. After the subs are dialed in, energize them with the same test tone. This should be enough to let you know if the Subs are your cup of tea.
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post #71 of 129 Old 02-13-2015, 10:57 AM
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Make sure Dynamic Volume and LFC are off on your Denon AVR.

And just to verify --- when you measured your FR and captured it as posted in the 1st post - you were measuring it from the MLP right?

There is literally an absurd amount of junk recommendations in this thread.
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post #72 of 129 Old 02-13-2015, 11:03 AM
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Quote:
Originally Posted by zorax2 View Post
I'd love to feel the chest thump for kick drums but also seem to be lacking the ear pressure in the ULF though to a lesser degree.
Im a room that size you should NOT lack the ULF ear pressure. I can maybe see the lack in chest thump but not the ULF. You really should get both!
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post #73 of 129 Old 02-13-2015, 11:35 AM
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Quote:
Originally Posted by zorax2 View Post
I'd love to feel the chest thump for kick drums but also seem to be lacking the ear pressure in the ULF though to a lesser degree.
Quote:
Originally Posted by zorax2 View Post
I run the Audyssey calibration for the subs at 78 dB (the max to keep in the green for level matching). This results in my subs having a -11 dB trim. I can than use the trim to boost the subs. I have no idea as to how high I can boost the subs as even at 120 dB they didn't seem to break a sweat.
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Originally Posted by primetimeguy View Post
I think he said that was subs only. Could be a huge suckout because of phase issues once the mains come into play.
primetimeguy is on the money here. Test the frequency response individually through the left, center and right speakers first with the sub off, then just the sub through the left speaker with the left speaker unplugged. Now measure each again with the sub turned on to see how they combine. I suspect you will find a big hole is created with sub and speakers playing that isn't there when one or the other is measured alone. If there is a big notch, experiment with adding 1-8' of distance to the subwoofer distance setting, measuring the combination at each setting. You will see no change in the sub response, but how they combine does change.

Finally, experiment with turning the room size control toward smaller (tapers down the deepest frequencies some) and creep the sub level up 2-8dB.
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post #74 of 129 Old 02-13-2015, 12:31 PM
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Quote:
Originally Posted by Alan P View Post
I shouldn't have said "never", it's just when trying to get the splice between mains and subs right it's best to do one speaker at a time. Also, I don't know why, all I know is that's how it's described in the guide.
I disagree with this. The only thing that matters is the FR of the system with everything playing together. It's the same reason you don't eq one sub flat, then the other. The end result with both subs playing together is what matters. I believe the same holds true with the speakers and subs....I want to see the combined frequency response resulting from the subs and both speakers playing together....that is what you hear when you play the system, and it will also have a large effect on the 60-120 Hz region.

Anyways, maybe people have good results eq'ing their subs with one speaker at a time? I did mine as one complete system.
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post #75 of 129 Old 02-13-2015, 01:00 PM
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I think any of that integration between the mains and the subs is moot in this particular conversation when the OP said he is running his subs 10-12dB hot over the mains. Any phase issues between the subs and the mains in 60-100hz kickdrum "slam" range are going to be completely overwhelmed by the nearly 12dB hot SPL of subs and even if the mains are out of phase with the subs - it's not going to do much to the OP's experience with kick drum slam.... (assuming the two subs are in phase correctly - which I must assume based of the quite reasonable SPL level he is hitting at 120dB and the note that at that SPL level the subs aren't at their absolute limit ---- If those two subs were out of phase he wouldn't be hitting 120dB levels with relative ease).

What I mean by this -

Your subwoofer crossover point is actually moved right on the frequency response plot over the setting you chose in your AVR when the subs are run hot.

This is easy to explain when you see a FR plot - so I googled a frequency response capture at random and then crudely redrew the subwoofer response up 10dB or so over the inital flat/reference FR capture. See the following: (don't critize the mspaint attempt too bad - it's not technical - it's just to illustrate the point that the crossover moves dramatically up when you raise the subwoofer trim.)





12dB is a doubling of a doubling ---- or a quadroupling of volume. I can't help but think that quadroupling of subwoofer levels over the mains levels would allow a phase issue to be of any major consequence in the uppper bass frequency perception --- which is what we are talking about relating to this particular OP.
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post #76 of 129 Old 02-13-2015, 01:04 PM
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Phase cancellation.

Turn one sub off and see if its louder.
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post #77 of 129 Old 02-13-2015, 01:07 PM
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@JimP ,
It's worth a try - but OP's SVS PB13 ultras are a completely different breed of sub than the ones I had if they can easily hit 120dB cleanly and be out of phase.

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post #78 of 129 Old 02-13-2015, 01:11 PM
 
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12dB is insanely hot, I tried it for a laugh...way over the top.
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post #79 of 129 Old 02-13-2015, 01:27 PM
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Quote:
Originally Posted by fatbottom
12dB is insanely hot ...
Yeah, I wonder how that actually sounds.

OP runs 24dB hot. I run 3dB hot with DEQ between -18dB and -14dB, and w/o DEQ above that.

At 3dB hot, everything is well-balanced. At 6dB hot, the bass is a little bit too pronounced. (Not overpowering, just unbalanced.)

I can't imagine (and I don't intend to find out) what running 24dB hot would sound like.

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post #80 of 129 Old 02-13-2015, 01:44 PM
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Quote:
Originally Posted by bear123 View Post
I disagree with this. The only thing that matters is the FR of the system with everything playing together. It's the same reason you don't eq one sub flat, then the other. The end result with both subs playing together is what matters. I believe the same holds true with the speakers and subs....I want to see the combined frequency response resulting from the subs and both speakers playing together....that is what you hear when you play the system, and it will also have a large effect on the 60-120 Hz region.

Anyways, maybe people have good results eq'ing their subs with one speaker at a time? I did mine as one complete system.
Keep in mind Bear, no matter how many subs you have the entire "sub system" is mono...the front speakers are stereo and receive different signals while playing content.
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post #81 of 129 Old 02-13-2015, 01:54 PM
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I have not figured out how to measure all 5.1/7.1 channels together as that is how we listen when watching a movie. How do they interact with FR, who knows?
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post #82 of 129 Old 02-13-2015, 02:13 PM
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^^^

But, like I just said, those speakers (during movies) are discrete sources. Running a sweep that included all 5 (or 7, or 9, or whatever) speakers would not tell you anything. For speakers that are discrete, you want to measure them individually (or with the sub channel) as this is the way they would play back the discrete content.
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post #83 of 129 Old 02-13-2015, 02:16 PM
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^^ Make sense. I always measure each channel + subs separately.
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post #84 of 129 Old 02-13-2015, 02:43 PM
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The OP is trying to get chest hit slam (80-300hz) from "6.5" low frequency drivers"...

Not going to happen.
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post #85 of 129 Old 02-13-2015, 02:48 PM
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Quote:
Originally Posted by Billy Boden View Post
The OP is trying to get chest hit slam (80-300hz) from "6.5" low frequency drivers"...

Not going to happen.
I mentioned it once, but I think it got lost in the shuffle. Perhaps this will be an option to consider:

http://www.powersoundaudio.com/products/mtm-210

OP would gain ten dB of headroom(99 dB efficient and dual 10" drivers) and boatloads of slam without upgrading subs. Or?
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post #86 of 129 Old 02-13-2015, 03:08 PM
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Quote:
Originally Posted by bear123 View Post
I mentioned it once, but I think it got lost in the shuffle. Perhaps this will be an option to consider:

http://www.powersoundaudio.com/products/mtm-210

OP would gain ten dB of headroom(99 dB efficient and dual 10" drivers) and boatloads of slam without upgrading subs. Or?
Those would work, too bad they are MTM's.

The OP can fuss with his subs all day long and will never get Slam/Punch/Chest Hit because it does not come from sub-woofers.
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post #87 of 129 Old 02-13-2015, 03:08 PM
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bear123,

Those MTM's aren't designed to have 'slam' IMO. (have we even defined slam?) I had JTR 228HT and I'm a big fan of JTR stuff in general (high efficiency stuff for that matter) --- my favorite speakers are the 212HT. Those PSA speakers are along the same design thread. To my knowledge nobody accused high efficiency speakers like that of possessing amazing midbass slam. They are made to be reference flat (which is pretty much the opposite of slam) --- lots of folk who buy gear like that 60hz, 70hz, 80hz port tuning - 98,99,100dB sensitivities say this type of accurate PA gear lacks midbass compared to what they are used to.

All I can figure out is the people who make that kind of statement are used to hearing car audio speakers, or old style Cerwin Vega type speakers which are all woofer, and very cheap mid and tweet -- both with very poor accuracy.

I'm afraid I agreed with your other points in this thread on sub steps, but I can't back you on this one. The PSA will be a better sounding speaker than what OP is currently running, and a more accurate speaker --- but they don't posses tons of midbass slam unless you decide to EQ them that way.

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post #88 of 129 Old 02-13-2015, 03:35 PM - Thread Starter
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Thank you all so much for your continuing suggestions. I've run everything again along with doing the sub "crawl" and I'll post step by step what I did. The end result was lousy but I'll explain and hope for help at the end of this reply.


To correct my earlier post my room is approximately 1,722 cubic feet and approximately 198 square feet.


A few folks have commented on the amplification for my Kef mains. When I originally bought them, I purchased a Pioneer 49TXi which was at the time their flagship model and had 165W. I didn't even stop to realize that the Denon doesn't have nearly as much power. I went to the Crown by Harmon amp calculator and entered 3.048 meters of MLP to speakers, 88 db efficiency, 85 dB desired SPL and 15 dB amplifier headroom. This calculator gave a recommendation of 147W. My Kef manual recommends an amp of 50 - 200W. I'm not sure it's completely relevant to my sub issue but given your feedback, I may need to look into getting amps for my mains.


On to the subs:


I made all measurements at 85 dB based on my UMIK-1, using ASIO drivers for HDMI and using the SPL meter within REW5. My sub mode is set to LFE not LFE + Mains. LFC is off. LPF for LFE is at 120 Hz. My Left and Right mains are toed in and 10' from my MLP. My center is 8.6' from MLP.


Scale on all graphs are 45 dB to 105 dB vertically and from 15 Hz to 200 Hz horizontally.


Left Front PB13 Ultra Only



Right rear PB-13 Ultra Only



Both PB13 Ultras at same time (+ 3 dB combined gain due to dual subs - I did not change AV Volume or gain on subs amps)



Pre-Audy - Left + Subs and Right + Subs overlaid with each other



Now, I did the full Audyssey calibration for the MLP only. For the subwoofer level matching, I adjusted the gain on each sub to show 75 dB on the setup screen. This resulted in sub 1 (front left) trim of -9 dB and sub 2 (right rear) of -9.5 dB. The strangest thing out of the whole calibration that I noticed was that my mains crossover was set to 150 Hz while my smaller Kef 202c and Kef 201s were set to a crossover of 40 dB. I turned Audyssey to on and turned off the Dynamic EQ and Dynamic Volume features. To measure the Left Main + Sub and Right Main + Sub using ASIO, I select Output 1 for left (#2 for right) and Output 4 subwoofer for the timing reference output.


Dual PB-13 Ultras only



Dual PB-13 Ultras with left front main speaker with Audyssey ON





Dual PB-13 Ultras with left front main speaker with Audyssey ON - Waterfall



I'm really thrown off by the waterfall as it is substantially different than what I had previously. I used the default settings with 350 ms and kept the volume at 85 dB. Perhaps the change from 75 dB to 85 dB may have impacted this.


Here's a link to the full REW measurements:
https://home.comcast.net/~rjfink/DualPB13Calib.mdat


Time to listen and evaluate
I put in U-571 as the depth charges are one of my favorite scenes for good bass. I set the volume to -10 dB and left the subs alone at their Audyssey defined trims of -9.0 and -9.5 dB. It was like there were no subwoofers at all. I then changed the subwoofer trims on both to 0 dB. While there was some perceptible bass - it was minimal and I know have had much, much better before where the room felt reasonably pressurized. I held my old school Radio Shack meter in hand and it was registering uncalibrated peaks of roughly 105 dB at the time. How can it possibly be that I have this sound level with what in this instance was now very little heard bass and virtually no room pressurization.


Something is seriously wrong and I just don't know what it is. While the waterfall now appears bloated, there still should be a feeling of some deep base in the room. In moving around in the room, I couldn't find a single good listening spot.


There is a silver lining - I ran a log sweep using the tone generator from 10 Hz to 100 Hz with a 20 second duration at 115 dB. Wow - there was some serious excursion at 10 dB. I really felt and heard the bass from 25 to 40 Hz and from 60 to 80 Hz. This leads me to believe the subs are working great and there is some other weird thing going on.


Thank you for your continued help in resolving this problem!
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post #89 of 129 Old 02-13-2015, 03:49 PM
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^^ If 85dB is desired SPL, is that the reference level average, or the peaks? Cuz if you only have enough amplification for 85db, you're at -20dB master volume.

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post #90 of 129 Old 02-13-2015, 03:52 PM
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I'm not expert, but your graph looks good to me. Could it be your source?



Last edited by Red99; 02-13-2015 at 03:57 PM.
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