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Multi-Way Conventional loudspeakers with crossovers

My first two way (Markaudio+Dayton)
My first two way (Markaudio+Dayton)
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Old 9th June 2018, 11:16 PM   #11
planet10 is online now planet10  Canada
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The L-Pad is typically the gain control in the power amplifier. Typically the bass needs to be turned down.

dave
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Old 13th June 2018, 04:10 PM   #12
peroz is offline peroz  Slovenia
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I looked at the dc250 now... seems to have roughly the same sensitivity as the CHR-70. Won't look as sexy as the 300, and probably won't use it in the next project, but anyway... would you guys say it is a more sensible choice?
I kind of decided not to go the PLLXO way, as people complain about it being a long trial and error path, possibly making the sound flat and dull.
Damn, I knew I shouldn't have started this multi-way journey:P

How is this for an idea:
I take the dc300, and make it help the chr70 to the point of baffle step "with its slope". Would it work? I hope I expressed myself clear enough... don't know how to put it.
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Old 13th June 2018, 05:14 PM   #13
chrisb is offline chrisb
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It's just as easy to poorly design a passive XO system that sounds flat and dull - or worse, as one using PLLXO / bi-amp.

One of the major advantages to the latter approach is that assuming you've got the required amps available, the cost of parts to provide the filter functions a low voltage / higher impedance levels will be much lower.

No matter which approach you take, it's always more advantageous to relieve the small wide-band driver of as much of the heavy lifting below around 300Hz as you can. Between 300 and, say 100Hz - unless in a very small room where localization won't be an issue - you'll want to go with bass support for each channel. They needn't be in the same enclosure.
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Last edited by chrisb; 13th June 2018 at 05:17 PM.
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Old 13th June 2018, 05:18 PM   #14
planet10 is online now planet10  Canada
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Quote:
Originally Posted by peroz View Post
... seems to have roughly the same sensitivity as the CHR-70...
With a passive XO you usually want the sensitivity of the woofer to be greater than the midTweeter and crossover somewhere in the range of 0.707-1 times the baffle step F3.

With a PLLXO (way easy than a passive XO but not as flexible) the sensitivities donít really matter, you adjust the end levels with the gain controls on the amps.

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Old 20th June 2018, 03:22 PM   #15
peroz is offline peroz  Slovenia
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I felt spendy for a moment and just ordered the big Daytons


Now I started playing with different simulators and design tools to come up with a viable design and found out the boxes will be very big. And heavy, which is good because I have small children.


The difference in sensitivity should kind of compensate with baffle step. The results of Edge are in the attachment.


I simulated frequency response with Leonard Audio Transmisson line and QSpeakers. Results are more or less the same: -3dB@30Hz.
Sims told me to make very big and long ports so I drew what I drew, but am thinking of maybe trying to do something with pvc pipes if that is an okay idea?

Please, review my attachments and let me know if there are any obvious and rookie design flaws. I know size will have to be recalculated when I know the thickness of the material and what I will do about the port, but this is basically it.
Attached Images
File Type: png edgechr70.png (60.6 KB, 218 views)
File Type: png LAbox.png (15.9 KB, 214 views)
File Type: png LAfr.png (38.8 KB, 213 views)
File Type: png dc300_2018-Jun-20_02-16-20PM-000_CustomizedView940725688_png.png (116.9 KB, 223 views)
File Type: png Screenshot_20180620_160740.png (85.7 KB, 217 views)
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Old 20th June 2018, 03:58 PM   #16
peroz is offline peroz  Slovenia
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Thinking some more... the problem might be the nearness of woofer to the FR unit... diffraction and stuff?
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Old 20th June 2018, 04:21 PM   #17
krivium is offline krivium  France
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Quote:
Thinking some more... the problem might be the nearness of woofer to the FR unit... diffraction and stuff?
hi,
theorically the woofer to FR centre to centre distance should be at most 1/4 wavelength of crossover frequency for best integration of both drivers (there is acoustic coupling if you follow this rule and both drivers should appears as one and only source).
E.G.: if you cut at 343hz so wavelength is 1m, so center to center spacing should be at most 25cm.

This may lead to some diffraction issues yes, but imho you'll end with diffraction issues anyway (as almost all loudspeakers) and to have the drivers not to integrate well may be more troublesome than diffraction.

From the pictures you linked in your post everything should be ok from my opinion ( or not worst than other implementation). This look like typical implementation for me, offset of Fullrange should help about diffraction and if you round the edge of box it should be even better.

Last edited by krivium; 20th June 2018 at 04:26 PM.
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Old 21st June 2018, 03:17 PM   #18
peroz is offline peroz  Slovenia
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Quote:
Originally Posted by krivium View Post
E.G.: if you cut at 343hz so wavelength is 1m, so center to center spacing should be at most 25cm.

So it the xo frequency is even lower, the drivers can easily be placed even farther apart. Good to know.


Quote:
...or not worst than other implementation). This look like typical implementation for me, offset of Fullrange should help about diffraction and if you round the edge of box it should be even better.
Okay, as long as it isn't worse than other projects.
I can't think of a way to better integrate two drivers like this, but if anyone has an idea, please share.
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Old 22nd June 2018, 04:07 PM   #19
peroz is offline peroz  Slovenia
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A construction question:
I drew the blue line to measure the lenght of the port and it seems I need that small "lip" over there to make it 45cm. Did I measure the lenght correctly? Is there a better way of constructing ports like this? Maybe make the turn sooner and make the additional wall also act as bracing?
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File Type: png dolzinaporta.png (759.8 KB, 57 views)
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Old 23rd June 2018, 12:32 AM   #20
Jerms is offline Jerms  United Kingdom
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Quote:
Originally Posted by peroz View Post
A construction question:
I drew the blue line to measure the lenght of the port and it seems I need that small "lip" over there to make it 45cm. Did I measure the lenght correctly? Is there a better way of constructing ports like this? Maybe make the turn sooner and make the additional wall also act as bracing?

Not really a surprise that there's a wealth of opinion and debate but hopefully the following article is factual.
Horn Folding - a brief study of the centerline vs advanced centerline method - AVS Forum | Home Theater Discussions And Reviews


J.
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