# mid tweeter config. on baffle



## vince (Oct 19, 2007)

Hello, I have built a WMTMW set of mains in the past year. All drivers are Peerless HDS except tweeter. I decided when designing to put the mids ontop one another vertically and set the tweeter to the side and of course the woofers top and bottom. I have been thinking about changing the mid tweet config. on the baffle to have the mids and tweeter in line vertically in dead center of cabinet. I don't seem to get real good imaging the way they are now. The reason I originally did this was to spread out any baffle diffraction issues, but now wondering if I may have comprimised imaging by doing so ??? It seems all the WMTMW arrays i have seen have all drivers in vert. line at center of baffle. Any thoughts on this ? want some opinions as this will be some amount of work. for x-over I am using the Behringer unit that has the built in parametric and time delay bells and wistles.
Thanks in advance,
Vince


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## mdrake (Jan 31, 2008)

I would think in theory it would help with the imaging and help flatten the off axis response. 
Do you have a picture of the speakers in question? 

Matt


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## lsiberian (Mar 24, 2009)

vince said:


> Hello, I have built a WMTMW set of mains in the past year. All drivers are Peerless HDS except tweeter. I decided when designing to put the mids ontop one another vertically and set the tweeter to the side and of course the woofers top and bottom. I have been thinking about changing the mid tweet config. on the baffle to have the mids and tweeter in line vertically in dead center of cabinet. I don't seem to get real good imaging the way they are now. The reason I originally did this was to spread out any baffle diffraction issues, but now wondering if I may have comprimised imaging by doing so ??? It seems all the WMTMW arrays i have seen have all drivers in vert. line at center of baffle. Any thoughts on this ? want some opinions as this will be some amount of work. for x-over I am using the Behringer unit that has the built in parametric and time delay bells and wistles.
> Thanks in advance,
> Vince


Horizontally aligned drivers are a no-no. I suggest you never build a speaker with them because off-axis response is dreadful. Meaning your first order reflections really do a number on the listening position.


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## vince (Oct 19, 2007)

Enough said ! I measured the space in the WMTMW design and have just enough room to salvage the current enclouser with a plunge router and cut out the mid tweet mounting area. I will then make a new mounting baffle with the mids and tweet in a vertical array. My only question then remains> should I line them up verticaly in dead center of cabinet or offset them left or right to make edge diffaction smother ??? nothing drastic I'm talking an inch or so on what measures a 10in. wide front baffle ?
Thanks,
Viince


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## mdrake (Jan 31, 2008)

lsiberian said:


> Horizontally aligned drivers are a no-no. I suggest you never build a speaker with them because off-axis response is dreadful. Meaning your first order reflections really do a number on the listening position.


I would have to whole heartedly agree with lsiberian! 

Martin Logan tried this with their fresco and the reviews I read were not too kind. 









They are now doing this. 
http://www.martinlogan.com/products/voyage


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## 1Michael (Nov 2, 2006)

Align them dead center:T


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## lsiberian (Mar 24, 2009)

Don't worry people do this with Centers all the time and it's ridiculous. If you ever want a great horizontal center box get a Coaxial driver.


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## mdrake (Jan 31, 2008)

On that wide of baffle are using any baffle step compensation in the crossover design?
This article discuss offsetting the drivers to one side to help with baffle step. 
It is an interesting read. http://sound.westhost.com/bafflestep.htm 

Based on an excellent formula developed by John Murphy (True Audio), we can calculate the frequency easily for the box ...
f3 = 115 / WB	(where WB is the baffle width in meters)
f3 = 380 / WB	(where WB is the baffle width in feet

Based the above formula I do not think mounting vertically in a row is going to give you any trouble. 

Matt


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## vince (Oct 19, 2007)

Thanks for all the useful info guy's ! I just spent twelve hours with a plunge router reworking the mid tweet config. no black lacquer yet. I have just did a dry run and the speaker sounds totally different ! the mids and tweet seem to gel together really nice, much smoother. I am going to use R plus D software with M and K mic and test later tonight. For xover I am using the Bheringer unit 48 db Butterworth, no delay right now, no eq right now. want to get a baseline and go from there. I did line up the drivers in perfect vert array. I need to find out how to post pics like you guy's. Tried when listing some stuff for sale but could not get it...
Thanks again,
Vince:T


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## mdrake (Jan 31, 2008)

I am very interested in seeing the pics of the new baffle. 

What do you think of the RPlusD software? I downloaded the trail version last month to do some measurements for our church but I am still trying to fully learn it. 

Are you using the 2496 as your crossover? 

One way to add pics is to use a free photo hosting website like Photobucket or Picasa albums and then you can use the url they provide to add pictures using the yellow mountain icon in the HT Shack. 

Matt


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## vince (Oct 19, 2007)

v


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## vince (Oct 19, 2007)

Sorry Mdrake, I reply to this the other day but it did not seem to post. I am using the 2496 for crossover duties, which I think is a great piece of gear. As for R plus D software, I have been using it for a couple of years now and it to me is worth every penny. I ordered the B and K calibrated mic and mic pre amp from Doug also, its very nice and simple (usb) to laptop works great. The mic comes with a calibration file on disk that loads into program (nice feature). I was years ago using the Behringer mic and thier Shark unit for testing, was not to user friendly in comparison to me but obviuosly cheaper in cost. R and D mic and pre was about $450.00. but I know is accurate.

As for the mods on my WMTMW speakers I have both done and they sound much better image wise ! when I get more time I will try and post pics. I have achieved a plus minus 1.5 db response from 65 to 10,000k with just spending time with cross points and slopes to me this is time better spent than messing with EQ settings, its amazing what you can do with response just spending hours with slope and x-over settings. I have come to the conclusion that the steepest slope is not ness. the best, it all depends on the drivers and how you can manipulate thier response using x over work. At this point I have not even set an EQ filter or delay, this will be next and then touch up the cross points.

I have had some 1" MDF milled to make two 12 inch subs (shiva) that will round out the two mains, they will serve as stands for the mains as well, powered with the Dayton 1000 watt sub amp (not a plate amp) so anyway that is where I am currently at with things. Sorry for the long winded post.
Thanks again for the input it has made a great improvment in staging and imaging !!!
vince:T


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## mdrake (Jan 31, 2008)

Awesome, thanks for the long winded post.  I would love to see some pictures of you setup! Some screen shots of the resutls in RplusD would be cool.... :whistling:

I have been using either the Radio Shack spl meter or borrowed mics to get my measurements but I think it is about time to invest in some proper equipment. What brand is the mic that you got with the R plus D software? 

Matt


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## vince (Oct 19, 2007)

If you go to R plus D website you can see the calibrated mic and mic preamp, it is B&K gear (german if not mistaken). You can contact Doug Plumb that owns the software via phone and order the hardware from him, I assume he is still using the same gear. I believe he is in canada. I will try and take some pics of the reconfiqured mains and get them posted when time permits. :sarcastic: I did not realize the post page rolled over to the second page duh !!
Vince


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## mdrake (Jan 31, 2008)

Do you want me remove the duplicate and if so which one top or bottom? 

Thanks for the info on the mic. I will have to do a google search. :T

Matt


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