# In wall speakers / baffle wall



## oublie (Jan 16, 2008)

Hi,

I'm in the middle of my home cinema built but i would like some advice please. I have build the main speakers 7 line arrays with 6 mids and 6 tweeters wired for a 4 ohm load. I designed the speakers to be wall mountable or in wall. I have attached a picture and you will notice that when i closed up the windows that had been in this room I only did a single brick layer so that the speakers can be mounted in the wall. My question is really to do with toe in - is it necessary or would i be better flush mounting the front left and right speaker. Also regarding exact angles is it necessary to be spot on with you angles for left and right as i am short at 40 degrees rather than 45 to get this spot on would mean cutting out the wall. I can tweak the angles for toe etc but it just means that there isn't as much room behind the speakers for damping material. The whole wall will be covered in a layer of absorbent material and the speakers will be 2.5meters / 9 feet from the listening position. Basically will i be okay or should i do the extra work now before i get to the soft furnishing and coverings stage?


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## ajinfla (May 10, 2009)

Hi oublie, are you asking whether the left and right speakers should be toed inward at a 45 degree (or so) angle?
Did you take any horizontal on/off axis measurements? What is the mid/tweeter XO frequency?

cheers


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## oublie (Jan 16, 2008)

hi, 

yeah do i need to toe in and if the angle between speakers is less than 45 degrees does it make a huge difference? haven't measured yet but xover is around 4k simply consisting of a high pass cap on the tweeter line which mates to the natural roll-off of the mid's high end based on inductance and the line array effect. Simulations and frequency response based on an 8 or 9 foot listening distance indicate -6 db at 80hz and rolloff starting around 15k at a 45 degrees angle i.e 2m back and 2m to the left or right. I see a lot of systems that seem to be flat across the front wall so is this correct or what do you recommend?

thanks.


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## ajinfla (May 10, 2009)

There is no generic "correct" toe-in angle for any system. That is completely speaker (mainly the polar response)/room dependent. With no horizontal measurements to go on, my recommendation would be: If you have multiple seats at that 8-9' distance, play some test noise across the fronts (Most AVRs have this) and listen for changes in tone/timbre sitting across your seating positions, with and without toe-in. See which sounds most consistent in each seat. Then play some movie tracks with dialog, etc. to confirm.

cheers


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## oublie (Jan 16, 2008)

Thanks for your help AJ I'll see what i can do


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