I'm slowly working on a MEH project that uses direct radiating woofers and midrange drivers. The midrange drivers cover 300 - 1800 Hz, the problem with using a compression driver for this range is that at the bottom of the range there is not much gain from the horn as this is below cutoff and so drivers with more surface area and excursion capability are required. I have to use direct radiating woofers as they physically won't fit onto the horn.
True in that this was done by using a ~70 Hz quadratic horn loaded Altec 604 duplex 5.1 HT system with the sealed rear chamber tuned empirically to get flattest response up to the 1600 Hz XO point [much smaller than anticipated], which later was dropped to the ~ideal 1200 Hz due to more horn gain than anticipated and of course the HF required frequency shaping EQ.
Then there's the Lowther, etc., compression loaded Tractrix horns..........
hr questions
HI everyone!
Sorry but my working week was very busy
I designed the phase plug measuring real woofer(6mm xmax)and shifting the same cone shape 10mm away but no ports in this time because
I've some questions for HR data:
1.1 If I want to simulate a synergy with reflex ports inside the horn is good to
select "rear vented" and use AP1 and Lpt for this front reflex?
1.2 If yes is ggod to select an "acoustic path lenght" in "combined output" menù with the difference od distance from rear of the woofer cabinet and mouth?
2 what really are VTC and ATC? I used already seen values from another thread...
Maybe I can not translate well hr info
3 I simulate the rcf front volume and cross area
volume is 1970 cc
area is 104 sq cm
my phase plug volume is 878 cc so my atc will be 1970-878=1092?
4 last but not least
how can I calculate front woofer port inside the horn?
Those will be boring questions for you
sorry in advance
Thank you
Ale
HI everyone!
Sorry but my working week was very busy
I designed the phase plug measuring real woofer(6mm xmax)and shifting the same cone shape 10mm away but no ports in this time because
I've some questions for HR data:
1.1 If I want to simulate a synergy with reflex ports inside the horn is good to
select "rear vented" and use AP1 and Lpt for this front reflex?
1.2 If yes is ggod to select an "acoustic path lenght" in "combined output" menù with the difference od distance from rear of the woofer cabinet and mouth?
2 what really are VTC and ATC? I used already seen values from another thread...
Maybe I can not translate well hr info
3 I simulate the rcf front volume and cross area
volume is 1970 cc
area is 104 sq cm
my phase plug volume is 878 cc so my atc will be 1970-878=1092?
4 last but not least
how can I calculate front woofer port inside the horn?
Those will be boring questions for you
sorry in advance
Thank you
Ale
Attachments
MEH WIZARD HR
HI
I've tried with "meh" in "input wizard" after reading the manual
my version of HR is 52.40
I simulated a tweeter response with thiele small parameters found on the web beacuse b&c not give t/s for dcx464.
I have a bad notch in 1000-2000hz range when I simulate only tweeter power1
and it changes when I change AP1 and AP2 woofer front port.
If I simulate reverse conical front port with ap1 150 ap2 50 the notch is very bad. with cilindrical (I would use 15mm baltic birch) I don't have the notch.
In this case HR simulate some interferences of front port in the horn flare?
I made some errors inputing some parameters?
thank you
Ale
HI
I've tried with "meh" in "input wizard" after reading the manual
my version of HR is 52.40
I simulated a tweeter response with thiele small parameters found on the web beacuse b&c not give t/s for dcx464.
I have a bad notch in 1000-2000hz range when I simulate only tweeter power1
and it changes when I change AP1 and AP2 woofer front port.
If I simulate reverse conical front port with ap1 150 ap2 50 the notch is very bad. with cilindrical (I would use 15mm baltic birch) I don't have the notch.
In this case HR simulate some interferences of front port in the horn flare?
I made some errors inputing some parameters?
thank you
Ale
Attachments
Your phase plug looks great!
I wish i could help more with HR.
I use the MEH input wizard, but only for the low/mid cones response, and don't pay any attention at all to the CD's output range.
HR has helped me get a good idea of the rear volume behind the cones, but past that I've been using measurements and trial and error prototyping.
And i've kinda come to believe with the larger cones like your doing, and i've been doing, just use a port or ports about 1/10th Sd, and either put a pair in the horn corners, or a single round one in the horn center....and as close as possible to the throat.
So for me, not much to model really.
Maybe others with more HR MEH experience will show up...
I wish i could help more with HR.
I use the MEH input wizard, but only for the low/mid cones response, and don't pay any attention at all to the CD's output range.
HR has helped me get a good idea of the rear volume behind the cones, but past that I've been using measurements and trial and error prototyping.
And i've kinda come to believe with the larger cones like your doing, and i've been doing, just use a port or ports about 1/10th Sd, and either put a pair in the horn corners, or a single round one in the horn center....and as close as possible to the throat.
So for me, not much to model really.
Maybe others with more HR MEH experience will show up...
I envy your CNC bigtime !!! Good for you !
For the primary horn and secondary flares, I've been using 12mm baltic-birch.
The pyramidal shape seems stronger and less resonant than a box, and doesn't seem to need the customary wall thickness.
(If plywood has significantly fewer plies than BB, i'd probably use 15mm ply.)
For parts of the cabinet that seal the cones in, and complete the box structure, I've used 15mm BB.
For the primary horn and secondary flares, I've been using 12mm baltic-birch.
The pyramidal shape seems stronger and less resonant than a box, and doesn't seem to need the customary wall thickness.
(If plywood has significantly fewer plies than BB, i'd probably use 15mm ply.)
For parts of the cabinet that seal the cones in, and complete the box structure, I've used 15mm BB.
The box without secondary flare should be 21kg plus 13kg for the drivers simulatore on fusion 360 entirely made of 15mm fenolic baltic birch
So i think to buy only 15mm bb to nave Little wasted wood.
The phase plug should be built with many sheets of BB
And 3d milled.
About woofer front ports I Will simulate different locations in the lenght of the horn.
Why do you think I Need to to put the Port near to the cd exit? Xover frequency Will be 600-800 regione and I Will use Active processing so delay Won't be and issue.
In the danley woofer Port are fare away from CD can you explain?
Thank you
Ale
So i think to buy only 15mm bb to nave Little wasted wood.
The phase plug should be built with many sheets of BB
And 3d milled.
About woofer front ports I Will simulate different locations in the lenght of the horn.
Why do you think I Need to to put the Port near to the cd exit? Xover frequency Will be 600-800 regione and I Will use Active processing so delay Won't be and issue.
In the danley woofer Port are fare away from CD can you explain?
Thank you
Ale
It's the whole 1/4 WL notch thingy, which says you'll get a deep null in the mids (low/mids in our cases), at the 1/4WL distance port to throat.
So to keep the notch above 800Hz, 1/4 WL math says keep the port within 10.8cm of throat....and is dang hard to do, huh....?
The phase plugs you built are the common way of trying to milk some higher response. Again, nice work.
So to keep the notch above 800Hz, 1/4 WL math says keep the port within 10.8cm of throat....and is dang hard to do, huh....?
The phase plugs you built are the common way of trying to milk some higher response. Again, nice work.
Hi
thanks Mark for your answer.
Meanwhile I milled a test tweeter mouth from spare wood to check the roughness and is perfect winhout sanding. in attached picture
With C lateral shapes I can move woofer very near to the hi's.
This week I will buy the baltic birch and start to mill!
Mids are 650rms each so 1300rms per channel.
I've found a used Proel PSW2660 (powersoft IPAL inside) 1300x2 on 4 ohms
for 250euros.
do You think amp power is enough to push to the max output capable?
Ale
thanks Mark for your answer.
Meanwhile I milled a test tweeter mouth from spare wood to check the roughness and is perfect winhout sanding. in attached picture
With C lateral shapes I can move woofer very near to the hi's.
This week I will buy the baltic birch and start to mill!
Mids are 650rms each so 1300rms per channel.
I've found a used Proel PSW2660 (powersoft IPAL inside) 1300x2 on 4 ohms
for 250euros.
do You think amp power is enough to push to the max output capable?
Ale
Attachments
update
hi everyone!
I was very busy
I post some building photos of the first top only for testing: no glue.
i tried a method a strange method to seal parts maybe is already used:
milled canals in joint for o-ring like seals like idraulic cylinders and engine heads. what do you think? is good for testing without anomalies in spectrum or distortion-phase problems?
I think I spent more time doing this cuttings with cnc than if I had done with a simple saw
Now I'm thinking about the subs:
the empty space in my car is about 1000x650x550cm so i'm thinking:
2xtham15 loaded with beyma 15lex1600nd 1600w rms 14,5mm xmax
look at hte simulation
4x small br cabs with at least same spl of the thams? any suggestions?
thank you guys!!
Ale
hi everyone!
I was very busy
I post some building photos of the first top only for testing: no glue.
i tried a method a strange method to seal parts maybe is already used:
milled canals in joint for o-ring like seals like idraulic cylinders and engine heads. what do you think? is good for testing without anomalies in spectrum or distortion-phase problems?
I think I spent more time doing this cuttings with cnc than if I had done with a simple saw
Now I'm thinking about the subs:
the empty space in my car is about 1000x650x550cm so i'm thinking:
2xtham15 loaded with beyma 15lex1600nd 1600w rms 14,5mm xmax
look at hte simulation
4x small br cabs with at least same spl of the thams? any suggestions?
thank you guys!!
Ale
Attachments
you might have more reasonable size if you add cardioid to the solution
Resistive port cardioid active speaker insipired by D&D 8C
Hi Ale, your build looks great !
The precision shows. Makes me wishful for some CNC capability.
Sorry i missed your post/ amp question from June.
Yes, i think that amp will work great with the mb12n351's. I use a PL340 with 1250W @ 4 ohms on a pair of them.
I've been comparing them to Faital 12pr320's on a current syn project and like them better. But their stronger motor adds about 1.75 kg each, and adds more weight than the project can bear. Sigh...
The throat adaptor you made looks especially cool.
Also like your idea for temporary construction. It beats mine of just using drywall screws to hold the horn together until i'm convinced the ports and such is right.
Good news is that i've yet to measure any improvement between the temporary screw job, and permanent glued-up joining.
(Unlike subs where it usually makes a ton of difference.)
The precision shows. Makes me wishful for some CNC capability.
Sorry i missed your post/ amp question from June.
Yes, i think that amp will work great with the mb12n351's. I use a PL340 with 1250W @ 4 ohms on a pair of them.
I've been comparing them to Faital 12pr320's on a current syn project and like them better. But their stronger motor adds about 1.75 kg each, and adds more weight than the project can bear. Sigh...
The throat adaptor you made looks especially cool.
Also like your idea for temporary construction. It beats mine of just using drywall screws to hold the horn together until i'm convinced the ports and such is right.
Good news is that i've yet to measure any improvement between the temporary screw job, and permanent glued-up joining.
(Unlike subs where it usually makes a ton of difference.)
Subs for synergy
Hi
I'm finishing the detachable secondary flare and I'm ready to test.
Meanwhile I'm trying to know which sub(s)
I Need for those tops.
Now i have in mind 1 2x18 ppsl 200l net for 45-120hz at 138db at peak Power.
With maybe 2 18sw115 or 2 lavoce san184.50 (vert Hood simulation)
I Remember Mark made some ppsls.
Any suggestions? My rear car space Is perfect for 2 tham15 so 360 360 Total.
Hi
I'm finishing the detachable secondary flare and I'm ready to test.
Meanwhile I'm trying to know which sub(s)
I Need for those tops.
Now i have in mind 1 2x18 ppsl 200l net for 45-120hz at 138db at peak Power.
With maybe 2 18sw115 or 2 lavoce san184.50 (vert Hood simulation)
I Remember Mark made some ppsls.
Any suggestions? My rear car space Is perfect for 2 tham15 so 360 360 Total.