# First post and first try with REW



## Sunny44 (Jan 4, 2008)

Hello All,

Having a lot of fun experimenting with REW. (maybe a little to much)

Here is my setup:

Basement L shaped semi dedicated HT room. 22'x12' with 7'10'" ceilings for main part of theater
and 12'x13' for bar/exercise area.

Def Tech 2006TL's, c2300 center and bpx for surrounds.
HSU VTFII MK III sub.(running in one port mode)
Marantz SR18EX receiver.

I've taken measurements of the sub from two of the seating positions and need some
input to see if I'm getting good results.
Also when I include the mains in the measurement they have a powered 8" sub with a level
control. Whats the best procedure to adjust this level to integrate with the sub.

Thanks!

Seat 1








Seat 2


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## Ivaols (Dec 29, 2006)

I think your respons look good, best overal in seat 2. 

Could you post a graph with both sub and mains?

When you add the mains, use phase to smooth the aerea around the crossover frequency. After that I play the pink noise from the receiver to match level, then I listen to determine if the sub is well integrated.


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## Sunny44 (Jan 4, 2008)

Ivaols,

Thanks for the quick reply.

I will run a test with the mains tonight.

Concering the mains, I guess I'm not sure what
to do with the level control on each main speaker which
is for the built-in powered sub.
I have my receivers main speaker setting set to SMALL so
that the 80HZ crossover is in effect.

I guess I would start off with this level control pretty low and
increase it to see how it fills in around the crossover?

Thanks!


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## Ivaols (Dec 29, 2006)

Hi,

I support you in the Small and 80 hz crossover setting.

Regarding the level i`m not quite following you. Do you have a pink noise you can set from your receiver to play from each speaker? If you do, use this pink noise and the RS meter to set correct level to each speaker, including the sub after you done calibrating.

The level in the built in sub amplifier should be set so that the gain on the receivers sub-output is around 0, when the sub match the other speakers level.


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## Sunny44 (Jan 4, 2008)

Ivaols,

I probably wasn't very clear, the sub out from my receiver is only going
to the HSU sub. The mains should only get 80hz and above because of
the small speaker setting. The mains level control (on the speaker itself) 
only effects the volumn of the built in sub, so the mains built in sub is only
handling mid base (with speakers set to small).

So now I have the level control from the receiver for each speaker and also the
level cotrol on the mains which control its built in sub. 

So I'm trying to figure out the best way to adjust this level control on the mains.
My guess is to adust it until the mid base area fills in.


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## Ivaols (Dec 29, 2006)

Aaaah, I see. I am not familiar with the concept of built in amplifier in the mains, but now I follow you.

I think what you say about adjusting the level in the mains to fill in the midbass makes sense. Still, at the end when you set level in the receiver for the mains I think you should aim for the same level as the sub, center and surround speakers. In that way you are sure not to set the mains hot compared to the rest.


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## Sunny44 (Jan 4, 2008)

OK I ran some more tests tonight with the sub and the mains.

Any comments or recommendations is greatly appreciated.

Not sure what the next step should be.

Thanks!

Seat 1








Seat 2


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## Ivaols (Dec 29, 2006)

Have you played around with the phase knob on the sub to smoothen out the aerea around the crossover? Is this respons the best average?

Is it important for you to have good sound in both seats, or do you want to tune one favorite seat?

This is important to know. If you want to use both I think it`s a overall good respons. If you want to use seat 1 as main seat, I would try to use the phase to reduse the peak around 80 hz. In other words, you have to answer the question before you continue.


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## Wayne A. Pflughaupt (Apr 13, 2006)

Sunny,

Do you have any other placement options? Seems highly peculiar that a Hsu sub would be done at 30 Hz.

Regards,
Wayne


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## Sunny44 (Jan 4, 2008)

Hi Wayne,

I was wondering about that also, I took a measurement closer to the sub and it moved from 30 to about 40. The sub is in the back corner of the room about 4ft away from the corner and 1ft from the wall.
I did try moving the sub out into the room, but that didn't make much difference. Will try the front of the
room tomorrow or this weekend or any other ideas anyone has.
I got the sub for Christmas and just started playing around with adjustments.
Does this look like a problem with the sub itself?

Thanks!


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## brucek (Apr 11, 2006)

> Does this look like a problem with the sub itself?


Put the sub in the middle of the room and do a near-field measure to find out. The only thing more accurate would be to take it outside......

brucek


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## Sunny44 (Jan 4, 2008)

brucek,

I will try that thanks.
I looked at Wayne's reply again and I think he meant down at 30hz not done correct?
If you look at the first attachments they are of the sub only and do show a dip at 30hz also.


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## brucek (Apr 11, 2006)

> If you look at the first attachments they are of the sub only and do show a dip at 30hz also


Yeah, the point was that an HSU sub won't have an inherent 30hz dip - it's the room causing it. Can you move the sub to remove it?

brucek


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## Wayne A. Pflughaupt (Apr 13, 2006)

Sunny44 said:


> I looked at Wayne's reply again and I think he meant down at 30hz not done correct?


I don’t have any experience with them, but I would think a Hsu sub should have no problem getting down to at least 25 Hz – unless maybe you have an unusually huge room...

I’d try measuring in various corners, if you have options. (If you don’t want to move the sub around that much, put it at the listening position and put the mic in the corners instead. It’ll get the same results.) Four-feet from the wall should be essentially the same as directly in-corner, but you never know...

Regards,
Wayne


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## Sunny44 (Jan 4, 2008)

brucek,

I tried the near-field measure, and the 30hz dip is gone and it looks pretty flat.

I moved the sub to the front of the room (need to get in better shape that sucker is heavy!)
and the 30hz dip is gone but I couldn't get the mains and the sub to integrate very well. Plus
there is just not enought room there.

I moved the sub back to its original position in the back corner and started thinking about the
closet thats on the back wall on the same side. (water softned and heater) It has a bi-folding
lovered door that doesn't seal and its not sheet rocked on the inside wall. I hung a heavy blanket on the opening and did some more measurments and the 30hz dip is reduced by 4-6db. Just to make sure I ran the test again with the same results. Very little else changes on the graph.

Does this make sence, I can't replace the door so any ideas, some treatment maybe?

Thanks for all the help!


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## brucek (Apr 11, 2006)

> Does this make sence


I does make sense. I have an huge dip that is only present when I open my kitchen door. If I shut it, my bass response is quite smooth. 

I would be more inclined to consider the move to the front of the room and make that work. There must be some wacky way you can make it physically fit. I'm sure it can also be made to integrated better with varying crossover, phase, distance timing etc...... 

brucek


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## Sunny44 (Jan 4, 2008)

brucek,

The only way the sub might fit in the front of the room is in between the center and right main
about 4' from the front right corner. The other problem is the front of the theater opens into a 13'x12'
area. (L shaped basement) I'll give it another try later, but is there anything I could do to fix the
30hz dip in its present position?

Thanks!


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## brucek (Apr 11, 2006)

Your question is a bit out of my knowledge area. I'll ask Bryan Pape from acoustics to look at this for you....

brucek


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## bpape (Sep 14, 2006)

Do it the old fashioned way - the crawl around method. Put the sub where your seat is and crawl around until you find a place with the smoothest response. Where you find that, put the sub there. People will think you're crazy but it works.

Bryan


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## Sunny44 (Jan 4, 2008)

Bryan,

Thanks I will try that, you do mean replacing the main seat with the sub (sub remains on floor right?)

brucek,

If I have to move it to the front, is the position between the center and right main OK or does it have to be in the corner.
I know its a lot of this is trial and error but I don't want to try the front again if its a bad location. Besides my wife is beginning to think I have lost it, wait till she sees me crawling around on the floor.


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## brucek (Apr 11, 2006)

> is the position between the center and right main OK or does it have to be in the corner.
> I know its a lot of this is trial and error but I don't want to try the front again if its a bad location. Besides my wife is beginning to think I have lost it, wait till she sees me crawling around on the floor.


I think a lot of people use the location between the main and center for their sub. Easy enough to measure and find out how effective it is in your case.

Yeah, that's good advice to physically position your sub at the listening position and then just do a bunch of REW tests at possible sub positions by moving the mic/meter around (considerably lighter device).

Actually, if you wait a little while (maybe a week), the next version of REW, that is presently in Beta testing, has a new RTA feature. This allows you to walk around with your microphone/meter and watch the PC display change in real time, rather than taking new measures. It is very, very cool and would be useful in your situation to establish the best sub location.....



> Besides my wife is beginning to think I have lost it, wait till she sees me crawling around on the floor.


And seriously, you know how much woman love those REW sweep sounds. Wait until you use the new RTA feature and you play Periodic Pink Noise for an hour or so. They love that....

brucek


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## Wayne A. Pflughaupt (Apr 13, 2006)

Better send her to the mall before you get started... 

Regards,
Wayne


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## Sunny44 (Jan 4, 2008)

OK, I tried the sub up in front of the room I think the graph looks
better, but its sounds terrible.

Very little base compared with it in the back of the room.

I've included the front and back graphs, it appears what look good doesn't necessarily sound
good or am I missing something? (besides base)

Is there anything I can do to take care of the 30hz dip when its in the back of the room?

If I could remove it, would it make much difference?

Front








Back


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## bpape (Sep 14, 2006)

I think a lot of it is perception. According to the graphs, you have much more bass with it in the front than in the back - though the back is smoother overall except for the one null around 26Hz.

The front is more deep bass but less upper bass. However, the front orientation is MUCH easier to EQ down to flat. But don't do that until you can treat the room and get the decay times right. I also suspect you THINK you have more bass in the back because the source is closer to you and you're getting more ringing (bad) back there.

Don't worry about corner placement - that's a crutch for more output at the expense of smoother frequency response. I have a strong feeling that you're just used to peaky, somewhat boomy bottom end that rings in your room and you're not quite sure what to make out of flatter frequency response. Yes - it's very different. But, after you live with it for a while and then try to go back, you won't want to.

Bryan


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## OvalNut (Jul 18, 2006)

> I have a strong feeling that you're just used to peaky, somewhat boomy bottom end that rings in your room and you're not quite sure what to make out of flatter frequency response. Yes - it's very different. But, after you live with it for a while and then try to go back, you won't want to.


That is so, so true. I would not want to go back to an untreated room now.


Tim
:drive:


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## Sunny44 (Jan 4, 2008)

Bryan,

I woundn't call it boomy, the rear position sounds tight and powerful, its just the front position lacks
inpact. 

Quote:
"But don't do that until you can treat the room and get the decay times right"

How do I go about doing this?


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## bpape (Sep 14, 2006)

You treat the room properly - that will help with some of the frequency response issues if properly placed. Then you just use MINIMAL EQ, only on the sub, and only to bring down peaks, not to try to raise dips.

Bryan


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## Sunny44 (Jan 4, 2008)

Bryan,

How do I treat my room properly, what is the procedure to determine what is needed?


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