# Some friendly advice please



## gperkins_1973 (Aug 25, 2008)

Hi guys,

Right here goes...

Further to mostly sorting out the hum issue I had I wanted to EQ the subs again. I have run many many sweeps to try and get a good reading with each sub and then combined and I am having issues so some advise would really be appreciated.

I am doing a 2D pic off the room now but I wanted to get some advise on location, nulls and peaks in my graphs whilst I am doing the plan so you can then see the measurements.

The subs are currently 113" away diagonally from each sub and they are facing inwards towards each other.

Please note that this is without Audyssey as I want to find the best position although limited before I re ran the Audyssey calibration.

Tuning is 17.5hz 

Pic 1 - Left sub
Pic 2 - Right sub
Pic 3 - both subs

Phase is 0 and LP is 100hz
Pic will explain more.

cheers

Graham


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## gperkins_1973 (Aug 25, 2008)

Sorry it took a while I had to measure everything. There is a dining table and chairs at the rear off the room which I have not drawn in.

Let me know what your thoughts are and what positioning can be bettered but remember I am short off options.

cheers

Graham


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## gperkins_1973 (Aug 25, 2008)

Here's some pics off the rear off the room. The door on the left leads to the hallway and the door at the back is a cupboard door which has a cupboard area off 38" wide by 96" long by 81" high. This is not a square more like a triangular shape because off the stairs.

The door on the right is the patio doors and there is a window on the right.

The wall on the left is an outside contcrete wall and is the rear wall. The rest are interior plaster boarded walls.

Let me know if you need any more information.

cheers

Graham


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## gperkins_1973 (Aug 25, 2008)

Updated sketchup file.

cheers

Graham


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## gperkins_1973 (Aug 25, 2008)

No takers?

Thinking about it, mods feel free to move to the acoustics forum.

cheers

Graham


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## robbo266317 (Sep 22, 2008)

Hi Graham, I just got back from shopping with the missus and I must say that's an _interesting_ shaped room you have there.

I must do some pics of my room as I found the flattest spot for me was at the rear of the room slightly off centre. (The room has an alcove off to one side at the rear.)

Can you put a sub at the listening position and use REW's RTA function to look for goods spots for the sub?


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

gperkins_1973 said:


> Let me know what your thoughts are and what positioning can be bettered but remember I am short off options.


Yeah, don’t see that you have any placement options, just orientation. You might try facing one or both forward and see what that gets you. As it is now, individual response is abysmal, but combined response is would not be difficult to equalize. It’s generally best to EQ both subs as one.

Regards,
Wayne


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## gperkins_1973 (Aug 25, 2008)

Sorry guys had to go to bed as it was 2am. Tried my hardest to stay up.

Lets say I started again what would be the best to look at the room. The problem I have had all along is that the old Q18s need big boxes so scrapping them is probably going to be my only option in order to get more optimum locations.

What do you guys think based on the room dimensions?

cheers

Graham


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## gperkins_1973 (Aug 25, 2008)

Is this likely to improve things until we sort out what is the next best steps? 

cheers

Graham


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## gperkins_1973 (Aug 25, 2008)

Here's another measurement with sub and speakers on my low tune. This is with Audyssey and no other EQ. Dont know why it is coming better. Now the speakers are calibrated to 75db and the sub to 84db. How come the sub is still showing to be lower in spl than the speakers when the sub is calibrated so hot.

Crossovers are:

Sub - 100hz
Speakers - 100hz

If I do the 80/80hz thing then I get a big dip at the crossover point.

Pic1 - sub only no smoothing
Pic2 - sub and speakers no smoothing
Pic3 - Sub and speakers with smoothing

Thoughts please.
Graham


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## robbo266317 (Sep 22, 2008)

A lot of folks turn the subs down a bit before running Audyssey and then they turn them back up again to get the extra bass they like.


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## gperkins_1973 (Aug 25, 2008)

Its wierd that no matter how I set the speaker/sub distance and phase to it doesn't make it flat in the crossover range. I've tried 80,100,120hz for the sub and a mix for the speakers and nothing gets better.

Would re running help. What I don't want to do is re run it and then it looks worse.

What do you think

cheers

Graham


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## gperkins_1973 (Aug 25, 2008)

Here's 3 pics to show the following

Pic 1 - sub only

Pic 2 - speakers only Full range These are positioned as in the first layout pic I uploaded.

Pic 3 - sub and speakers overlayed.

Could this be a speaker placement issue?

Thoughts

Graham


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## gperkins_1973 (Aug 25, 2008)

Heres the speakers facing diagonally. Looks better but the massive 80hz dip is there still


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## gperkins_1973 (Aug 25, 2008)

Right I have re run Audyssey twice and the second time I decided to run it without the EQ.2 (hpf) and run in low tune so just going through the EP4000 only. 

This is the final result I have got and I have pretty much exhausted myself to the stage where I need a stiff drink.

This is with no smoothing and the sub is calibrated to 84db and the speakers 75db. The speakers still look a bit higher spl than the sub even though the sub is almost 10db hot. REW is not seeing the 10db hot which is really wierd. Oh well.

I will play some music today and watch a film tonight to see how it sounds.

I do need to look into what options would be better and am open to suggestions from you experts. Pretty please.

cheers

Graham


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

gperkins_1973 said:


> Is this likely to improve things...?


It’s impossible for anyone to predict that. You’ll just have to try it and see.

That said, in some rooms you get worse response the further the sub gets from the corner and/or boundaries. With boxes that big you inevitably end up with the driver being several feet from one or the other, or both, as you have now. So you might try turning the cabinet backwards, with the driver facing the wall, and the cabinet a foot or so away from the wall. 




> Pic1 - sub only no smoothing


Looks like the crossover’s low pass isn’t working...


Regards,
Wayne


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## gperkins_1973 (Aug 25, 2008)

Wayne,

Did you see the last graph?

cheers

Graham


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

No, I didn't notice that we had rolled over to Page 2. That last one looks good. :T

Regards
Wayne


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## gperkins_1973 (Aug 25, 2008)

Wayne,

I listened to a load off music yesterday and I have to say I was very impressed. It sounded very clean. I watched How to train your dragon and WOW. I had the onkyo on -15db and no excursion issues although there was some serious driver movement going on. The BFD clip lights came on a couple off times but that was only on the big bass parts. But then I am running 10db hot so I guess that would be normal.

cheers

Graham


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