Hi,
I'm building a pair of 2.5-way floorstanding speakers, sealed cabinet, each woofer with its own separate volume.
Cabinet is almost ready, except for the front baffle, now it's time to think at the preliminary crossover circuit.
I just want to know if calculating a normal 2-way circuit (with paralleled woofers, obvious) it's the correct working step, before thinking at the next inductor and other components for the 0.5 way.
Thanks
I'm building a pair of 2.5-way floorstanding speakers, sealed cabinet, each woofer with its own separate volume.
Cabinet is almost ready, except for the front baffle, now it's time to think at the preliminary crossover circuit.
I just want to know if calculating a normal 2-way circuit (with paralleled woofers, obvious) it's the correct working step, before thinking at the next inductor and other components for the 0.5 way.
Thanks
Puppetnation said:
Hi,
No it is not. Its more like a normal 2 way that ignores
BSC with an extra driver added to implement the BSC.
Calculating a c/o ? sets the alarm bells ringing ......
http://www.rjbaudio.com/Audiofiles/FRDtools.html
http://www.geocities.com/woove99/Spkrbldg/
http://www.zaphaudio.com/
http://www.rjbaudio.com/projects.html
http://www.troelsgravesen.dk/Diy_Loudspeaker_Projects.htm
http://www.humblehomemadehifi.com/
http://htguide.com/forum/forumdisplay.php4?f=39
/sreten.sreten said:Hi,
At the c/o point mid to treble you only have one active bass/mid unit.
Ok Sreten, but my question was different:
I'd like to know if it's correct to start with a normal 2-way crossover layout (with 2 paralleled midwoofers, so calculate the LP inductor for 2 paralleled speakers) and THEN thinking at the additional 0.5 way components and BSC...
In a few words, can I imagine a normal 2-way crossover with 2 par. woofers and -only later- working at the second woofer circuitry?
Attachments
Hi,
Like I said no its not. If the 2 way c/o design ignores BSC then
the 2.5 way design is a single MT 2-way with an added 0.5 driver.
You cannot start with a paralled MTM type 2-way crossover that
ignores BSC and then move on to implementing 0.5 way BSC
with the same crossover components and a 0.5 way inductor.
This should be blindingly obvious ........
/sreten.
Like I said no its not. If the 2 way c/o design ignores BSC then
the 2.5 way design is a single MT 2-way with an added 0.5 driver.
You cannot start with a paralled MTM type 2-way crossover that
ignores BSC and then move on to implementing 0.5 way BSC
with the same crossover components and a 0.5 way inductor.
This should be blindingly obvious ........
/sreten.I second that, starting with two paralleled woofers in a 2 way crossover and then adding a 0.5 way on one will obviously mess things at the crossover point.
Starting with one woofer in a 2 way crossover and then adding the 0.5 way woofer makes more sense, although there is still a possibility to mess things at the crossover if the 0.5way woofer has still some output - in the end, the overall response must be considered.
Starting with one woofer in a 2 way crossover and then adding the 0.5 way woofer makes more sense, although there is still a possibility to mess things at the crossover if the 0.5way woofer has still some output - in the end, the overall response must be considered.
sreten said:Hi,
Like I said no its not. If the 2 way c/o design ignores BSC then
the 2.5 way design is a single MT 2-way with an added 0.5 driver.
You cannot start with a paralled MTM type 2-way crossover that
ignores BSC and then move on to implementing 0.5 way BSC
with the same crossover components and a 0.5 way inductor.
This should be blindingly obvious ........
Ok, it's clear now.
Thanks
Puppetnation said:
Hi,
They can share the mid/treble LP stage but at the c/o point the 0.5
way should well down due to the series 0.5 way inductor and so
high impedance, not affecting much the other drivers impedance.
That is : the c/o is much nearer one driver values than 2 parallel.
FWIW 2.5ways can be problematic if the drivers are
not suitable, hence presumably JWJ's question.
/sreten.Well, I'm no expert certainly, but I think we need some clarification.
Are you starting with two bass speakers and a tweeter, and later planning to add a third bass speaker, OR are you planning to later convert the second existing bass speaker to the new .5 aspect of your speaker system?
If you are adding a third woofer to convert from a 2.0 to a 2.5 that is a completely different ballgame than using the existing two woofers in a 2.0 and later converting those same two woofers from a 2.0 into a 2.5.
I would say that if you are adding a third woofer for the .5 aspect, then you can calculate the 2.0 crossover aspect now and it should work later.
But if you are going to convert one of the existing woofers to the .5 aspect, then the load impedances on the crossover completely change and the original 2.0 crossover is worthless.
Or am I missing something?
Steve/bluewizard
Are you starting with two bass speakers and a tweeter, and later planning to add a third bass speaker, OR are you planning to later convert the second existing bass speaker to the new .5 aspect of your speaker system?
If you are adding a third woofer to convert from a 2.0 to a 2.5 that is a completely different ballgame than using the existing two woofers in a 2.0 and later converting those same two woofers from a 2.0 into a 2.5.
I would say that if you are adding a third woofer for the .5 aspect, then you can calculate the 2.0 crossover aspect now and it should work later.
But if you are going to convert one of the existing woofers to the .5 aspect, then the load impedances on the crossover completely change and the original 2.0 crossover is worthless.
Or am I missing something?
Steve/bluewizard
Here is how I have done it. I use a cascaded XO layout for the woofers. AFAIK, Jeff Bagby was the first DIYer I remember using this.
I use a low pass for the full range woofer and off the driver side of the XO I cascade the .5 way XO and driver. What this does is give me the roughly first order low pass for the .5 way driver, which then transitions to a steeper slope as it approaches the MT XO point.
Zaph uses this approach in his new ZRT design (the 2.5 way version) seen here:
http://www.zaphaudio.com/ZRT.html
Please note though that this isn't something that can be gotten right with just textbook formulas. Getting the proper baffle step compensation along with proper integration of the mid and tweeter really requires actual measurements and XO software.
Regards,
Dennis
I use a low pass for the full range woofer and off the driver side of the XO I cascade the .5 way XO and driver. What this does is give me the roughly first order low pass for the .5 way driver, which then transitions to a steeper slope as it approaches the MT XO point.
Zaph uses this approach in his new ZRT design (the 2.5 way version) seen here:
http://www.zaphaudio.com/ZRT.html
Please note though that this isn't something that can be gotten right with just textbook formulas. Getting the proper baffle step compensation along with proper integration of the mid and tweeter really requires actual measurements and XO software.
Regards,
Dennis
You can use a program that "knows" 2.5 way. Like "Passive Crossover Designer". It is a excel sheet. Excellent.
No need to design a 2way than add 0.5.
Don't use directly the driver graphs from data_sheet. Measure the drivers on actual baffle. If you have no measurement microphone than use a baffle simulator. You can find all tools at http://www.pvconsultants.com/audio/frdgroup.htm
No need to design a 2way than add 0.5.
Don't use directly the driver graphs from data_sheet. Measure the drivers on actual baffle. If you have no measurement microphone than use a baffle simulator. You can find all tools at http://www.pvconsultants.com/audio/frdgroup.htm
sreten said:
Hi,
Have you bought the drivers ? If so no comment, but if not .....
I just own one pair of MW166, the rest will come.
They're among the few midwoofers good for a sealed enclosure (nowadays most loudspeakers are made with bass-reflex in mind).
Other stuff (Dyns, Eton etc.) were too expensive for me.
Anyway, please express your opinion, I'm here to learn...
Puppetnation said:
I just own one pair of MW166, the rest will come.
They're among the few midwoofers good for a sealed enclosure
(nowadays most loudspeakers are made with bass-reflex in mind).
Other stuff (Dyns, Eton etc.) were too expensive for me.
Anyway, please express your opinion, I'm here to learn...
Hi,
Well actually it is not my opinion, check out the test of
the MW166 at zaphaudio.com , its not great at $107.
I do not know of any independant test of the $80 MDT32S,
the known / tested benchmarks for DIY softdome tweeters
are the $40 Seas 27TDFC / and $80 Peerless 810921.
/sreten.- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.