I know people who used it 2nd order at 1kHz mated with a 15" woofer. It was the original series Heil AMT altough. I don't know how the modern ones stack up. The woofer was an acient JBL D130 in a modified Jensen Imperial cabinet. This is a diy system that was build in the early 80's with a passive crossover and was also used for (infamous) home parties at relative loud volume at that time. I was not arround then (i was still a kid), i heared the system quiet a lot about 15 years ago, and it's still running.
But why first order?
But why first order?
1. so you want to start with the Heil AMT with 1e order crossover
2. define your crossoverpoint - i take 4khz
3. choose a driver which is isn’t to big for better off-axis reponse - for example a 4.5 - 6 inch midrange - go for high sensitivity and a nice response till 7-8khz
4. now you need to decide the lower crossoverpoint of the midrange - i would go to 4-way so i would choose a bigger midrange driver of 6 inch which i could cross around 800-1000hz to a 12 or 15 inch woofer
5. the woofer will need a lowboost and i would cross it higher order between 100-200hz
6. go for an efficient bass system - several big woofers without baffle or a smaller system with more distance between front an backwaves to improve efficiency - keep in mind that crossing higher than 100-200 hz will give problems with resonancefrequencies
2. define your crossoverpoint - i take 4khz
3. choose a driver which is isn’t to big for better off-axis reponse - for example a 4.5 - 6 inch midrange - go for high sensitivity and a nice response till 7-8khz
4. now you need to decide the lower crossoverpoint of the midrange - i would go to 4-way so i would choose a bigger midrange driver of 6 inch which i could cross around 800-1000hz to a 12 or 15 inch woofer
5. the woofer will need a lowboost and i would cross it higher order between 100-200hz
6. go for an efficient bass system - several big woofers without baffle or a smaller system with more distance between front an backwaves to improve efficiency - keep in mind that crossing higher than 100-200 hz will give problems with resonancefrequencies
Last edited:
This is nearly impossible.
As driver response in OB is narrow then overlapping at least in bass and midrange is not possible.
https://www.linkwitzlab.com/images/graphics/Point_dipole_on_baffle.png
Funny, while I am reading this I am listening to a mono mockup I made earlier that is almost as you suggest. I crossed the Heil @ 3Khz to chinese DIATONE P6S-BA Alnico clone which hands off @ 600hz to a 12".
Sounds very smooth and sounds surprisingly good at low as well as medium listening levels.
Haven't heard it loud yet because the family is still asleep with a jet lag.
I spent countless hours combining a myriad of drivers with my mini DSP A/B 'ing different crossover arrangements and consistently liked first order over any other arrangement. So at some point I concluded I am just a 1st order guy.
Is there an article explaining this in more detail? I am not sure I fully understand.
with your dsp flex8 you can just try different slopes -
i use an opendrc-da8 myself and i correct for phase en frequencyresponse
you might have looked for good aff-axis response based on bad size-match, a big midwoofer crossing to a small tweeter - lower order crossover might improve such a bad (bad because of very different off-axis responses) combination
physical design of your speaker is your first goal, good off-axis response has to do with the physical design
a smaller midrange (4-5.5 inch) has wider dispersion in the range 2.5-4.5khz wher you can cross them to your tweeter
because of their size they should be crossed around 1-1.5khz which is a bit high for a 12 inch woofer, so you pick a 6.5-10 inch woofer which might be to small to fill the gap from 100hz, so there you need a bigger woofer - and there is your 5 way speaker
3000 and up : Heil AMT
1500-3000 : 4-5.5 inch
300-1500 : 7-10 inch
100-300 : 12-18 inch
below 100 : several 18 or 21 inch
i use an opendrc-da8 myself and i correct for phase en frequencyresponse
you might have looked for good aff-axis response based on bad size-match, a big midwoofer crossing to a small tweeter - lower order crossover might improve such a bad (bad because of very different off-axis responses) combination
physical design of your speaker is your first goal, good off-axis response has to do with the physical design
a smaller midrange (4-5.5 inch) has wider dispersion in the range 2.5-4.5khz wher you can cross them to your tweeter
because of their size they should be crossed around 1-1.5khz which is a bit high for a 12 inch woofer, so you pick a 6.5-10 inch woofer which might be to small to fill the gap from 100hz, so there you need a bigger woofer - and there is your 5 way speaker
3000 and up : Heil AMT
1500-3000 : 4-5.5 inch
300-1500 : 7-10 inch
100-300 : 12-18 inch
below 100 : several 18 or 21 inch
Last edited:
So IMO and given the difficult design implementation, I’d simply place the two 18 “woofers side by side on the ground plane as a base…….you’ll pick up some gain from the floor and won’t have to worry about the woofer on top in an MTM creating yet another lobe or a secondary floor or ceiling bounce.
I’d have those playing only to 80hz with an XO point around 100hz…..first order as you indicate…..if you choose 21” you’re going to run into listening axis height issues once you get to a tweeter or MTM section with 1st order filters…..
Next up would be your midbass driver……..1st order to midranges…….12” driver is about as large as you can go without a directivity issue
Oh…and with 1st order filters forget the WMTMW arrangement…..the center to center distances are just too far to pull this off. 12-15” midbass……6” class midrange and then your Heil crossed up around 4K…….with a 1st order high pass, the Heil just might be able to pull that off.
I will probably try make it four way because of the flex 8 capability.
3000 and up : Heil AMT
600-3000 : 2x 5"
120-600 : 2x12"
below 120 : 2x21" inch or 3x18"
i use this :
3000 and up Mundorf 17D2.2 - no baffle
1100-3000 scanspeak 10F - no baffle
180-1100 seas excel w22 - minimal baffle
30-180 b&c 18sw115 - in a big and open pvc tube
all phase corrected
your setup will allow for higher dynamics with less distortion
Last edited:
Perhaps you would be interested in my webpage: https://www.fedde.nu/audio/chill-baffle3.html
I chose for Daudio AT 15" woofers with 6" 18 sounds high power mid and ESS AMT. Woofers are end game, but quite expensive. For bigger room, you could double (or triple) them up. Mid and AMT could also be doubled up for extra level.
Also interesting to look into is Steinway Lyngdorf model B. They use six 12" woofers per side with 5" mid and AMT. Great bass.
I chose for Daudio AT 15" woofers with 6" 18 sounds high power mid and ESS AMT. Woofers are end game, but quite expensive. For bigger room, you could double (or triple) them up. Mid and AMT could also be doubled up for extra level.
Also interesting to look into is Steinway Lyngdorf model B. They use six 12" woofers per side with 5" mid and AMT. Great bass.
Very nice build! I cannot find any info on the woofers you used. Is there a more precise part number for them?
I was thinking exactly the same to get acceptable MTM spacing.
Maybe flanked by 2 Pluvia 7 PHD drivers? Crossed at 3.5Khz or 4khz?
Center to center spacing can be close to 12 cm.
Last edited:
I would love to hear those. Usually very expensive speakers don't do much for me and I hardly ever think "if I were rich I would buy them"........but I could see these in my mansion 😊
Something like this..,..
The MTM section is around 88dB 1w/1m sensitive, the rest well over 100dB. So I guess this would only work with active crossovers.
Last edited:
Bummer, I just see in the Mundorf datasheet that they advise a 5k crossover for first order. But kudos for Mundorf to indicate a 1st order crossover. I cannot remember another datasheet that does. Usually I only see 2nd or maybe 3rd order crossover frequency indicated.