# Pb12+/2



## jr1414 (Nov 28, 2007)

Just made a deal on a used PB12+/2 with the 12.3 drivers. Very eager to pick it up this weekend and get some real bass working in my living room. This unit will be replacing my DT SuperCube2, which never seemed to be very accurate. It could fill the space with a lot of low frequency noise, but was never sharp enough for me on kick drums, fast bass lines, etc. 

Any advice for setup in a 3200 ft^3 room? I'm using DT Mythos 2's for Main L and R, DT Mythos 3 for center and DT Mythos Gems for surrounds (mounted high firing down in the rear). I'm mostly interested in accurate tight, low bass as opposed to high SPL's. I'm considering using 2 port blockers, but would love to hear what you all may have to say.

Hopefully this will hold me over until I can get a PB13 Ultra, or maybe I'll be pleased enough I won't need it at all.

Thanks.


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## Josuah (Apr 26, 2006)

I think going from the SuperCube2 to a PB12+/2 is going to be a surprising experience for you. It's going to sound tons better.

If high SPL is not as important to you as accurate low extension, then run it at its lowest tune and don't play movies loud. Maybe -20dB from reference at 1 meter. Just work on placement and EQ.


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## jr1414 (Nov 28, 2007)

Thanks. I've got a 3 yr old, so there aren't many nights I can listen to a movie too loud anyway, so I think that's my best bet. I'm definitely looking forward to the improvement over the SC2. I'll let you know my first impressions on Sat night or Sunday, if you can tear me away from my couch...


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## Sonnie (Apr 11, 2006)

What's your room like? Have you got a floorplan sketch and do you have placement options?

I've got two of these and they are awesome!


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## jerome (Apr 24, 2007)

Congratulation on your upgrade! You won't regret it, Pb12+/2 is a great sub which can deliver both low frequencies and high SPL :T

As will most of the subwoofers, you will have to try several setups and placement in order to know what works best for you. PB12+/2 is a big sub with low WAF so you may not have so many options, unfortunately. It will be difficult to hide it, maybe behind your sofa ???

As Sonnie say a floorplan sketch would be a good idea to get better feedback.


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## jr1414 (Nov 28, 2007)

I do have a sketch, it's a scanned .jpg. How would I go about attaching it here?


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## jerome (Apr 24, 2007)

Simple: first you have to write your post using the _Advanced_ version. If you're typing your message in the _Quick Reply_ window then click the _Go Advanced_ button.
When you're in the advanced version then go down the page and check out the section called _Attach Files_. Click the _Manage Attachments_ button to attach files to your post. Upload your files using the new pop-up window.

You're done ! :T


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## Sonnie (Apr 11, 2006)

Here's another method with pictures... :T

Here's the attachment method broken down fairly well for a graph, works the same for an image.


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## jr1414 (Nov 28, 2007)

Ok, Here goes. This is a diagram with my proposed sub location. The wife doesn't mind it located here. I an also find a spot about 2/3 of the way along the left side wall, which would end up alongside where the couch is located. Of course I have the option of anywhere on the front wall, but want to stay away from the stairs down and hallway to the right


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## Sonnie (Apr 11, 2006)

Yep... I like that location as you should benefit from some pretty nice room gain. You will need to take some response measurements to make sure you don't experience any peaks that need to be tamed. Those peaks can cause your bass to sound one-notish.


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## jerome (Apr 24, 2007)

You could also place it below your SL speaker if you like it better and/or don't have enough space in the current position.

Some people like to have their subwoofer(s) on the front to get the sound _in their face_, some other like it from the back. The best is of course to have it both in the front and the back !!! :bigsmile:


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## jr1414 (Nov 28, 2007)

I've got the single band PEQ to help tame a single peak, don't have a BFD yet, but one will be on the way soon (hopefully). I use a Phonic PAA3 to model room response, it's a great tool and I highly recommend it. You can find the info for it here: 

http://www.phonic.com/en/product/detail.php?group_name=&languageid=1&group=en&product_no=paa3

Best part is it's work-related for me, so it was a business expense!!!


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## Josuah (Apr 26, 2006)

A common approach for placing a sub is to stick it in your seat and play stuff while walking around and sticking your head where you'd think of placing the sub for real. You want to pick a place where things sound strongest, but not boomy. The problem with corner loading is it might be too boomy.


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## Sonnie (Apr 11, 2006)

Good idea... the BFD will fix boomy... and if I were going to place the sub in the main listening position, I would take my mic and place it in various locations at about the height of the sub driver and measure the responses with REW... then pick the best response/location combo to work with. You would rather have peaks to tame than dips that may be difficult to deal with.


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## jr1414 (Nov 28, 2007)

Joshua, that's an interesting procedure, but makes a reasonable amount of sense. I may actually try that and see how it works. Could possibly save a lot of time taming peaks when I get the BFD.

Sonnie, I've actually just started reading up on the use of the BFD (don't have it yet, but hope to pick one up soon). I hadn't actually heard of REW until you just mentioned it. I did a quick search and started doing some reading of the help files, but I think I'll need some time to determine what I will need to make all of the connections first. 

I can actually do RTA with the PAA3, so that should give me a good enough base to determine proper location and integration, and will even make it easy to see where I might want to use the PEQ to tame a single spike. It's nice to see the whole spectrum at once using pink noise without having to plot individual frequencies. I'll do both of course, but I think that pink noise shows some things that single-band analysis does not. I'm sure you would see some differences between running REW in real time (waterfall mode?) on pink noise to what you'd actually see if you plotted each frequency. Or maybe I'm dead wrong...


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## Sonnie (Apr 11, 2006)

I'm not a fresh on REW as our pros in that forum, but I do know that using sweeps would probably give you the best picture of your response in each location. You can also load all of those sweeps into one graph.


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## Josuah (Apr 26, 2006)

As I meant boominess, EQ isn't going to fix it. You're just going to have too many reflections of that particular frequency going back and forth. EQ will decrease the amplitude of that sound wave and consequently the lifetime, but it'll still be there. You want the amplitude, but not the lifetime. Faster decay is better. Moving the sub a foot or out of a "boxy" area (e.g. the corner) could completely avoid that problem.

The idea of placing a sub at your listening position and moving your head around is a widely accepted practice and works well because you're basically ray-tracing in reverse. That's why you want the sub to be close to where your head would be, and then your head to be close to where your sub would be.


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## jr1414 (Nov 28, 2007)

Ok, I'm just going to start this post with YES!!! I've finally joined the ranks with some real, tight, accurate bass! I actually got my pants to flap as I sat on the couch during the heat ray scene in WOTW!!!

I got home last night and started setting up the sub in the room. I haven't gotten out the PAA3 yet, but I did a quick go around with a couple of different sub locations, just to see where I might like to place the sub. I couldn't doo too much as my 3 yr old was going to sleep in an hour after I got home, but I moved the sub around from spot to spot. 

I also tried putting it on the couch where I sit to listen around the room for good locations. It's no fun lifting this thing, I can promise you that! I did wind up placing it in the corner designated in my original sketch above. I have a BFP coming soon, so I'll finish the setup once that arrives. Ordered up some cables late last night to make the hookups.

I was already impressed with some material that I never realized had underlying bass lines I've never heard before. Even at very low playback levels (couldn't wake up my son, you know) I heard detail and notes that never existed in my system before. I'm impressed by how accurate it could play at very low levels, and it added depth and clarity to the soundstage on music as well. It think this is going to be the absolute best investment I've ever made in my system, but I'll reserve that until I see what kind of difference the BFD and REW can make.

Thanks to all here that have given advice, it is greatly appreciated. I'll post more as I get to do some critical listening, probably later in the week.


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## thxgoon (Feb 23, 2007)

Josuah said:


> As I meant boominess, EQ isn't going to fix it. You're just going to have too many reflections of that particular frequency going back and forth. EQ will decrease the amplitude of that sound wave and consequently the lifetime, but it'll still be there.


Check out this thread. I was a bit surprised by it.

Putting your sub in your listening spot and moving your head around the room is the best and simplest approach to finding the best sub location IMO. Using REW makes it even sweeter because you can quickly take measurements and see exactly how each location performs.

Congrats on your upgrade! Those Mythos are awesome speakers and I bet the SVS will be a great match!


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## jr1414 (Nov 28, 2007)

Thanks, I really appreciate it. I've done just a little listening today as we had our first snow in NY and my 3 year old wanted to spend the day playing in the snow with his cousins. An unexpected trip to CT later and it left with with about 30 minutes to do some intense listening. I think I've definitely found some peaks, and I played with the PEQ a little. Sounds good to my ear, but I'm sure the PAA3 will show some errors in my hearing.

As far as how they work with the Mythos speakers, it's like they're made for each other. I swear that they sound much clearer since adding the sub, I couldn't be happier right now.

I listened to some jazz tonight and some rock. A good friend just released an album, so I've been hearing some of this stuff from the early recordings and I'm super familiar with it. Heard some things in some of the bass lines that I'd never heard before. Kick drums had such a natural depth and decay it was spooky. Sounded like I was in one of the small NYC clubs he used to play at a table in front of the stage. Actually gave me goose bumps. Can't wait to get him up here when he's got a chance to hear his thoughts as well.


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## Josuah (Apr 26, 2006)

thxgoon said:


> Check out this thread. I was a bit surprised by it.


Isn't that the same thing I said? :dontknow:

The cut-filter improved the decay, but it did so by decreasing the SPL. If there is no spike there to begin with, then you've made your time plot look nice in terms of when everything drops to zero, but your initial response curve would no longer be flat.

Boominess is a bad word to use. I shouldn't have used it. What I meant by boominess is long decay time. You could have a completely flat frequency response but lots of reflections (long decay) which will make things all yucky. The same thing happens from speakers that measure flat but have cabinet resonances that result in extended decay times centered around certain frequencies.


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## thxgoon (Feb 23, 2007)

Josuah said:


> Isn't that the same thing I said? :dontknow:


I'm not sure and I don't want to strew too far off topic but this is the part of the thread in which I was referring. While I'm not totally clear on the matter it seems that a room node and response bump are essentially the same thing - that is the bump is due to the room amplification which is responsible for the extra decay time ...

" It's because the EQ filter, just like the modal resonances of a room, has a time response that acts like a 2nd order biquad. If I apply an EQ filter with the same Q and opposite gain of a room mode, I would completely counteract the effect of the mode. See the time component of the filter (just like a room mode). It rings out, and still isn't in the noise after 300msec. You see, EQ filters don't just affect level. This is why they're so effective at equalizing at modal frequencies below 100Hz."

jr1414 - neat to hear your listening impressions.. I think live music is very revealing of speakers and subwoofers. With a good system it seems as though you are evaluating the system at the venue along with the mix rather than your own system. Very fun indeed!


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## jr1414 (Nov 28, 2007)

Great observations fellas. I happen to agree with you both. I agree with Josuah in that you should attempt to eliminate as many room nodes as possible through proper placement of the subwoofer in the room. The less peaks to tame, the better.

I also agree with thx goon in that it's also great to know that if you're limited in positioning options, and for the additional peaks and valleys in the FR you can not tame by placement alone, that we have a tool that not only corrects the gain, but also attempts to correct to the proper decay as well. 

I can't wait for the BFD to get here now. Looking for RCA to 1/4" mono cables now and also have the USB-MIDI cable coming from my musician friend this weekend. Not sure if they are still shipping the early firmware with the BFD, or if mine will be 1.4. I'll find out when it gets here. From what I've read, manual entry is not so difficult anyway.


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