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Old 15th May 2005, 07:55 PM   #31
meil is offline meil  Denmark
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You are using a W22 together with a XT19, isnít that a big mouthful for the small XT19.
Does the waveguide really help that much in the low end?

I have just read about the waveguide and it is interesting.
A highly regarded DIY man here in Denmark has for years spoken very positive about the waveguide.
I might look closer in to it. But it makes the distance between the woofer and tweeter greater. And that is not always desirable.
How do you cross between your W22 and the XT19?

I brought my SS R29 used. The man was selling because he wants to use the SS D29 instead. (That says it all)

Ok you have a subwoofer then I understand you have no problems with the level.

If I should do some open baffle system, then Iíll properly go with a closed woofer system up to around 100-200 and from thereon open baffle.
Iím not bound to the speakers I have bought, if I see something better I just change.

Thanks again for the inspiration
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Old 15th May 2005, 10:44 PM   #32
AJinFLA is offline AJinFLA  United States
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Default XO

The waveguide increased the output by more than 15db at XO, which was 1.3K 8th order. It works somewhat opposite of how the open baffle mounted woofer - which requires a boost (eq) to maintain flat response. You have to compensate by (eq) rolling off (reducing) the response at a much higher frequency to flatten it. This is where people get confused. They see the very low XO frequency and say no way the driver should be crossed that low. But the driver is already seeing -15db power (@ XO) and does not distort even at high volumes. The low XO is exactly what allows for the driver spacing!
Look again at some of the finest studio monitors you cab buy (or perhaps listen to firsthand)
http://www.genelec.com/products/bi_amp.php
Perhaps you have already heard these fine Fins in Denmark?
One of the most popular here is this
http://www.mackie.com/products/hr824/index.html
Driver spacing there looks very close to mine as that waveguide is (I believe) approx 6.5" dia.
Here is the XT19 in another well reviewed monitor XO'd @ 1.8k (no waveguide!)
http://www.abluesky.com/p_s_gb/p3s2s1.html
Now the SS R29 I take to mean as the R2904/70000x, but what is a SS D29?
Also I only use the sub when very high levels are required and it only operates (when used) below 35-40hz. The 4 XLS 12s (H-frame) provide PLENTY output down to 25hz under "normal" listening - where the sub is turned off!
BTW, you may already have your dipole ready midbass in your old speaker! The (7"?) AudioTech should be fine down to 150hz (but not lower) if it has good Xmax. Linkwitz has a SPL calculator if you know Sd and Xmax. Just plug in and you will have an idea. 2 10" XLS (you already have 1/side) will give you the same output as his orion if you use same D for baffle. It gets a little tricky when you take the sub that high (150hz) but it can be done. You may well have most of your drivers already!
You could still used a sealed box to augment your LF if you wish (below 40hz).

Cheers
AJ

ps. sorry for the crappy pics, I need a new digital cam!!
Attached Images
File Type: jpg loft pics 004.jpg (65.9 KB, 310 views)
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Old 16th May 2005, 05:12 AM   #33
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Hey Aj, I really like what you've done with the your speakers. I'm also a very big fan of the Mackie and Genelecs and wondered how much the waveguide played apart in their incredible midrange. BTW, where did you get your waveguide and how did you optimize it's performance for that tweeter?
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Old 16th May 2005, 05:39 AM   #34
meil is offline meil  Denmark
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Hi again AJ

I might try making a test baffle together with waveguide.
The open-baffle is much easier to make than an ordinary cabinet.

I have not two but four C-Quenze 15H.

You were earlier using a link to D29 not the R29. The only difference is the diagram. The D29 is using a normal dome.

The pictures are ok.
How did you make your waveguide ?

Nice writing to you, but I will not be on the internet for a while
Iím catching an airplane for North Carolina this morning.

Thanks again for open up my eyes for open baffle and waveguide.

Br.
Meil
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Old 16th May 2005, 06:09 PM   #35
AJinFLA is offline AJinFLA  United States
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Default Waveguide

Hi Conscious,
to say that I "optimized" the waveguide might be stretching things a bit . I simply bought an existing screw on type CD horn available for pro audio compression tweeters - and modified it to fit the XT-19. The model # is PH65 by Pyle. There are others that are identical. I saw one that is sold by MCM in New Jersey. I bought a few and tried different mouth profiles until I got what I thought was reasonable, meaning very little change in the on/off axis response EXCEPT for the low end where there is a considerable rise in the response. I used TrueRTA to measure the on/off axis response. I wish I could tell you that I used a lot of computer modeling, but I did not. It was mostly by experimentation. I did have some basic ideas for a starting point, which was 1) a conical constant directivity type horn 2) Shallow profile with as wide coverage as possible (110deg in this case) 3) good coupling to the driver so that there are no abrupt transitions at the mouth of the guide (horn). I am often asked these questions, but I am far from an expert. There is info out there to draw from. There is a gentleman by the name Dr Geddes who is doing a lot of good work in this area. There are others also. But the main problem, as I have stated before, is implementation - for the DIYer. You must have some measurement capability and a willingness to experiment. I am still at the beginning stage, but I do intend to investigate areas such as stored energy and non-linear distortion introduced (or not) by the guide. So much to do. So little time.

Cheers
AJ

ps. thanks Meil I realize now that by D29 you mean the D2904/71000x - the jewel of my eye
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Old 16th May 2005, 06:34 PM   #36
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I really like what you've done with the your speakers.
David,

Where on the island are you?

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Old 18th May 2005, 04:03 AM   #37
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AJ, thanks for your description and kudo's for the DIY waveguide, I've never seen that before. I wonder if some of the pro-sound DIYers are doing the same thing? Must be if there are waveguide dealers for the public - have you seen any other DIY implementations?

Hey Dave, didn't we do this before:
http://www.diyaudio.com/forums/showt...678#post597678

Just kidding, of course bro. Being a mod, I'm sure you can't keep us all straight, I'm in Nanaimo.
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Old 18th May 2005, 06:10 AM   #38
AJinFLA is offline AJinFLA  United States
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Hi conscious,
be careful what you call a waveguide, it has a tendency to rile some people. Dr Geddes (I believe) said that all waveguides are horns, but not all horns are waveguides. In the case of the "Pro" sounders, I think the intent is maximizing SPL, since requirements in open space (outdoors) are vastly different than your living room. You're talking Horn here. I'm not looking for 140db at home. I actually don't care too much about the efficiency, since my system is fully active. Again super high SPL is not the goal. Now there is also the Pro driver DIYer for home use, thats seeking high efficiency because they are using a very low power tube amp. A rather bizzare state of affairs IMHO. Thats probably Horn also. But I digress. The "waveguide" as I implement it serves only to increase the low end output of the driver, while attempting to minimally affect the upper ranges. It also serves to create controlled directivity throughout the range of the driver, but be minimally restrictive in coverage. Especially as it transitions to the midbass at XO. A low gain horn if you ask some. I'm sure there are other DIY implementations out there, but I couldn't find too many. I think I piqued the interest of some other DIYers on other boards, but it does get rather complicated. Not beginner material. Lots of headache.
Give it a shot, you'll see

Cheers

AJ
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Old 18th May 2005, 07:10 AM   #39
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Hey Dave, didn't we do this before:
Yep we did... my brain is getting feeble as i approach old-age

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Old 31st May 2005, 03:18 AM   #40
AJinFLA is offline AJinFLA  United States
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Default Driver update

Here is some data on the MW180 I chose to use (untill I can afford the AudioTechs Meil ).
http://206.13.113.199/ncdiyaudio/mar...o/Dynaudio.htm
The nonlinear results (and linear) are subject to debate because of the nearfield measurements. Still valuable info. Hopefully more testing like this will be done by other individuals like Mark K. Many thanks to him for giving us his time. I wish I had a garage
Lastly, I hope the file size is ok for Mr. Fitzpatrick

Cheers

AJ
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