PB2-ISD Calibration

monkeyphant

Here is the graph:

Dr. Spec

That is a very decent looking start to a house curve. Messing around with your phase control in 10 degree increments and running a sweep each time will more than likely identify a setting which significantly reduces the severity of that null at 80 Hz.

In fact try 180 to start, and then try 110 (works well in my room - a shot in the dark, really).

Regardless, you should have NO shortage of power and impact in the 20-60 Hz region - there are no ugly nulls in that bandwidth at all and you have really strong room gain. I say all you need to do for more power/impact is wick up the gain setting. That's the really good news in all of this.

Also, how does your master volume affect the speakers and the sub - I noted you could alter the gain independently for the speakers. Are you sure you are providing an equal amount of gain to both the speakers and the sub as you increase your Master Volume setting?

Doc

monkeyphant

That is a very decent looking start to a house curve. Messing around with your phase control in 10 degree increments and running a sweep each time will more than likely identify a setting which significantly reduces the severity of that null at 80 Hz.

Thanks, Doc. Adjusting the phase control and doing additional FR
sweeps is my next step...

Also, how does your master volume affect the speakers and the sub - I noted you could alter the gain independently for the speakers. Are you sure you are providing an equal amount of gain to both the speakers and the sub as you increase your Master Volume setting?

I'm pretty sure I'm providing an equal amount of gain to both. I use my AVR as a preamp processor. The AVR preamp outputs are connected to my power amplifiers. The only time I alter the gain (turn them down completely) is when I take sub measurements, other then that they are at full volume (I think, but I'll make sure when I get home tonight).

MP

monkeyphant

Doc:
I checked and I am providing an equal amount of gain to both the speakers and the sub as I increase my Master Volume setting. I used my new AVIA Calibration Disc for the first time last night. Strange thing...using the old VE at 75 db gave me insufficient PB2-ISD power even wicking up the sub plate gain to 78db; BUT with the AVIA, all surrounds at 85db and the sub at 89db, was more than enough power. I still want to do some FR sweep measurements, but the PB2 is not suffering from a lack of power/ volume/pressure anymore.

MP

Dr. Spec

Originally posted by monkeyphant
I still want to do some FR sweep measurements, but the PB2 is not suffering from a lack of power/ volume/pressure anymore.

MP

Case closed; VE was the culprit. I swear by Avia for basic video and audio calibration. I even run Avia cool for the sub 85/83 and it's still strong. But I used to run 88-89 when I first had my PB2+, so I can appreciate your current taste in bass. As long as the PB2-ISD is living up to its billing and you are happy, that's all that matters.

monkeyphant

Thanks to DOC, pjdami, tryrrthg, PolkWannabie ....and a special thanks to VE for raising my blood pressure and keeping me awake at night...:p

MP

pjdami

MP,

Congratulations on resolving the problem to your liking and you are welcome.

Please do post a FR of the "post Avia" calibration FR because I am curious as to what the difference is between the new graph and the old one. So you didn't change any settings on the AVR or DVD player eh? How much more gain (relative to notches) did you have to add to the plate amp?

Just curious. You actually looked pretty strong in bass response before based on the curve. I just wanted to see what the differences are.

I have successfully used the Sound and Vision and Avia DVDs before; they are both made by Ovation. The S & V just seems to be the stripped down version and it's only 20 bucks.

monkeyphant

How much more gain (relative to notches) did you have to add to the plate amp?

PJ

That's a good question. Since I'm not at home, I can only guess. I would say from about 1/4 to about a notch or two before 1/2, but that's with the PB2 running too hot at 89db. I'll work on a new FR sweep this weekend.

MP

pjdami

MP,

So that means that you are close to the 12 o'clock position when looking at the sub amp plate dial? That's about where I am too.

You should be well into the 100's with SPL between 20 - 30 hz with an increase in the sub amp plate there. Looks like you are going to be a little hot between 30 - 40 hz as well. That is fine if it is to you liking but there are some things you can do as if you find this setting a little too bass heavy for music. Really depends on you though and how it sounds to you.

When you get a chance this weekend I would also like to see what kind of SPLs you are getting from the movie tracks you origianlly posted. Before and after.

Happy Easter!

monkeyphant

PJ

Please do post a FR of the "post Avia" calibration FR because I am curious as to what the difference is between the new graph and the old one.

I did my OVE FR sweep at -20RL. I'm thinking to do the AVIA FR sweep at about -30RL or so, since I don't know what to expect with the new AVIA calibration. It shouldn't make a difference since we are comparing frequency response.

When you get a chance this weekend I would also like to see what kind of SPLs you are getting from the movie tracks you origianlly posted. Before and after.

I'll reduce the plate amp gain to RL (83db) and record the movie SPLs again from the primary sitting position at -10RL.

You have a nice holiday!

MP

monkeyphant

PJ

Please do post a FR of the "post Avia" calibration FR because I am curious as to what the difference is between the new graph and the old one.

I did my OVE FR sweep at -20RL. I'm thinking to do the AVIA FR sweep at about -30RL or so, since I don't know what to expect with the new AVIA calibration. It shouldn't make a difference since we are comparing frequency response.

When you get a chance this weekend I would also like to see what kind of SPLs you are getting from the movie tracks you origianlly posted. Before and after.

I'll reduce the plate amp gain to RL (83db) and record the movie SPLs again from the primary sitting position at -10RL.

You have a nice holiday!

MP

monkeyphant

When you get a chance this weekend I would also like to see what kind of SPLs you are getting from the movie tracks you origianlly posted. Before and after.

LOTR: The Ring Drop
Iron Giant: Iron Giant fires on Battle Cruiser
U571: German Sub under depth charge attack after destroying
merchant vessel (highest SPL)

The OVE measurements were taken at -10db below RL with the AVR at -6 and the PB2 calibrated at 75db.

The AVIA measurements were also taken at -10db below RL with the AVR at -6 and the PB2 calibrated at 83 db.

..........OVE.......................AVIA
..........Calibration..............Calibration
LOTR...94db.....................104db
IG.......96db.....................106db
U571...95db.....................107db

Avg.....95db.....................105.6db

monkeyphant

PJ
Here is the FR sweep showing the AVIA calibration with the Phase at 0 and 90 degrees at -20 RL.:

monkeyphant

Please do post a FR of the "post Avia" calibration FR because I am curious as to what the difference is between the new graph and the old one.

...and the OVE and Post AVIA calibration at -20RL at 0 Phase:

Dr. Spec

Great work, MP. The right calibration disc makes ALL the difference, doesn't it? I bet you can FEEL that extra 10+ dB can't you? :cool:

Nice to see the phase control making a difference. Keep tweaking it; 110 degrees works well in my room.

Also try enabling the low pass at the highest setting and see what happens to that 90 Hz null. I know, it sounds counterintuitive, but just try it. Also, enabling the low pass is not for rookies - you need FR sweep capability to evaluate its effect and otherwise I recommend leaving it disabled.

monkeyphant

Great work, MP. The right calibration disc makes ALL the difference, doesn't it? I bet you can FEEL that extra 10+ dB can't you?

Thanks DOC...coming from you that's a real compliment! That extra 10+ db had me laughing like a mad scientist, especially the Iron Giant scene which I played about three or four times in a row. Man the house shook....

My daughter told me that when I was doing the SPL movie calibration , Mrs. Monkey said: "I hate when your father does that. He's going to lose his hearing if he keeps that up :mad: !"

Mrs. MP can't take a joke...

Dr. Spec

And everyone should note that MP is running his sub FLAT at 83 dB with Avia.

A truly powerful sub does not need to be run hot in order to impress. I run my PB2-Ultra the same way for HT, and even cooler for music (81 dB).

The asking price is almost ridiculously low when you consider what that sub is capable of.

Believe me, you've got some gas left in that tank; your PB2 isn't even breaking a sweat at 105-107 dB peaks at the seat. No need to push it louder, but it's nice to know you've got headroom galore to keep dynamics sharp and distortion low.

monkeyphant

Doc:

Here's the latest FR sweep results using my Stryke Calibration disc at -20RL all speakers plus the PB2. I've gone from 90 degrees to 45 degrees. Also, I used my AVIA Disc to check the sub level which was at about 85db after running the FR sweeps. I am going to wick the plate gain back to 83 db. As you said, there's no reason to run the PB2 hot.

Dr. Spec

Wow! Fabulous looking curve. Relatively flat from 100-40 Hz for accuracy on music, and then look out - free room gain for the super deep HT stuff! The best of both worlds.

A first hand demonstration of the power of a CV phase control - a very good tool in the right hands. As you now know, it affects far more than the response at just the xo frequency. Really great work. I bet the sub sounds just awesome on both music and HT.

Now that you have the sub dialed in, I would plug a port, drop the tune switch, and measure the increase in deep output. At the volumes you are hitting, you can afford to plug a port. You'll notice a difference on a handful of DVDs with true 15-20 Hz content. Something like U-571 dts, Revolutions, or the Daredevil dts bar fight scene are good examples.

I'm betting you'll get good in-room extension to 16-17 Hz with a port plugged. Try it and see how you like it.

After you calibrate to 83 dB with all ports open, up the sub level 1.5 clicks at the AVR when you plug a port. This will mostly compensate for the volume lost above the tune point and the curve in the 100-30 Hz region should look almost the same. You will get a slightly flatter looking curve in the 30-20 Hz region, and reap another 5 Hz extension at the very bottom. It should troll deeper than sin with a port plugged.

Doc

faster100

I gotta get off my **** and do some FR sweeps and tune this isd i have.. run the dve disk... and hopefully i get that s&V disk soon in the mail... alotta good data here guys

pjdami

Looking really good monkeyphant. Hard work and patience has rewarded you. As Doc has suggested, (and I found this to be the case as well) porting a plug will help flatten that hump and give you deeper extension. Man, looks like you have some good acoustics for bass in that room.

I gotta get off my **** and do some FR sweeps and tune this isd i have

Faster.. Do it! You will learn a lot about your subwoofer and optimal room placement that way. This is one way to squeeze every little bit of optimal performance out of the hard earned money you spent on a sub.

Dr. Spec

Man, looks like you have some good acoustics for bass in that room.

Disgusting, isn't it? Some guys have all the luck. My room is the same way. You've really struggled with your room acoustics, Paul.

faster100

Hey, Doc... what program are they useing to make that graph.. I just ran the test tones... and need something to make a graph with to see the ups and downs...

Dr. Spec

Just a simple Excel spreadsheet. I developed one about two years ago and it spread all over the internet. Lots of other variations floating around too.

faster100

I have your spread sheet, But what did monkey use to make that graph picture?? above

faster100

wow either i did something wrong or this graph is crazy

pjdami

yeah faster. Something isn't right. Can you post the sheet with the data? Let's see what is going on.

P.

HBombToo

Yikes!

faster100

how do i post the excel sheet

pjdami

should be able to post it just like you did the graph above. Just a different sheet in the workbook. Same principle.

Or you can copy your desktop image and paste it in a .jpg / .gif file

Just curious. Is your raw uncorrected data that low in dbs (56)from 40 hz to 85 hz?