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Multi-Way Conventional loudspeakers with crossovers

Best way to balance speaker for a flat response
Best way to balance speaker for a flat response
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Old 10th August 2019, 07:30 PM   #11
adason is offline adason  United States
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Old 10th August 2019, 09:38 PM   #12
Deano452 is offline Deano452  Australia
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Originally Posted by adason View Post
True, very true. Don't neglect phase.
I was tweeking small bookshelf, based on aurum cantus ac130 and horn loaded fountek ribbon, meant to be used with subs, and finally achieved ruller flat on axis, almost perfect off axis behaviour, and flat phase...now that's one neutral sounding well behaving no fatigue sound. All it needs is better subs to sit on.
It would be ruler helpful as to what did you " tweak " , resistor values , caps to alter the crossover point . Did you put in a Lpad ? What type of crossover is in it , e.g. 2nd order , 1st order ( not with a fountek surely) or what ?
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Old 10th August 2019, 11:12 PM   #13
adason is offline adason  United States
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Yes, 1st order with fountek, how else do you achieve flat phase. 7kHz with lpad.
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Old 11th August 2019, 12:46 AM   #14
sal87 is offline sal87  United Kingdom
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so just to shed some light on my situation:

I've built a pair of TH18 tapped horns which have come out amazing and sound excellent so i wanted to then build a pair of tops to go with them but also be able to use these tops by themselves when needed.
Each box is fairly large at 650mm tall, 450mm deep and 400mm wide. the box houses 1x 18sound 12nd930 woofer, 1x BMS 4552 tweeter with 18sound waveguide and 1x faital pro M5N8-80 mid-driver.

I then thought i'd try something a little different and go for a point source type design and put the tweeter and midrange drivers in front of the woofer which is on the baffle but in free air (this was an after thought, hence why the free air) this is most probably the start of my issues!

I've gotta say that i used Xsim to try and build a crossover for these drivers and to be fair, i got a great result but went the active route in the end.

Anyway, i've decided to build another pair of boxes in the next month or so which will house 1x 18sound 12nd930 woofer and 1 Beyma 5CX200FE coaxial driver, both of which will be on the baffle in the traditional position of woofer sitting beneath the coaxial.
I should add i'll be using Beyma's crossover for the coaxial driver and will use my DBX driverack to then crossover the Beyma and the 18sound driver. I reckon using Beyma's crossover will give me a much better base to work with as well.

So is there any way of simulating my box without building it just yet?
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Old 11th August 2019, 02:25 AM   #15
AllenB is offline AllenB  Australia
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Originally Posted by sal87 View Post
i used Xsim to try and build a crossover for these drivers and to be fair, i got a great result but went the active route in the end.
This is only an insignificant choice in the bigger process of making a crossover.
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Originally Posted by scottjoplin View Post
It is a classic case of needing to measure, then the question becomes where to place the microphone
Yes.. can't build a crossover without knowing what it is supposed to manipulate.
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Old 11th August 2019, 02:47 AM   #16
gabdx is offline gabdx  Canada
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I added 3 other steps in my xo building.

first there is the research of the drivers,
then the box size
then models are made, measured, room in taken into consideration, volume levels etc
I build the actual final products with damping etc
listen and measure for issues, if issue, go back to prototype, fix it, rebuild or fix final design

do many types of XO, listen for what sounds best, where the xo can cross without issues, beam and thd and imd

then do final xo accordingly, measure again, should be spot on.

0 need to do ear, only to hear how low/high the drivers sound nice, this is done by using multiple type of xo, listening random music and hear any problems which are not obvious in the thd curve.

there is also a great deal of research to get the desired best response curve, just inputing a straight line or getting the response flat is never a good idea, better stay within +/- 2 db or 3 db and take what sounds best there,

it sounds trivial but this process takes many years
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Old 11th August 2019, 03:00 AM   #17
gabdx is offline gabdx  Canada
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one mistake people make is to have the xo right , but wrong.

like the xo point should be for the best dispersion AND where both drivers are getting tired. if at the xo point one driver is making more distortion than the other it is a failed xo.

also it is plain dumb to start filtering the best driver when the other one has higher distortion at the same frequency. Or if the distorted driver is not filtered enough and the peaks of resonances and distortion are rising faster than the filter curve, this is typical for midranges and tweeters.

As the midrange is filtered and tweeter takes over, the mid range is 2n or 1st order and start screaming distortion inside the tweeter, and vice versa. this is trivial but it needs to be properly designed regarding at least 2n and 3rd order THD, it is a time consuming process.
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Old 11th August 2019, 07:51 AM   #18
sal87 is offline sal87  United Kingdom
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As Iím buying Beymaís dedicated crossover, surely thatíll make life easier, right?
Then itís a question of crossing over the woofer with the coaxial.

These speakers are for a live band so room acoustics canít really be taken into consideration as itíll constantly change.

Gotta be honest, a few of the last comments have confused the shite out of me.

Once Iíve built the box, is using pink noise a good way of measuring? Or a mix of pink noise and music?

What do I look for in the pink noise response?
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Old 11th August 2019, 08:23 AM   #19
sal87 is offline sal87  United Kingdom
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How do you guys choose drivers? What do you look for?
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Old 11th August 2019, 08:36 AM   #20
mbrennwa is offline mbrennwa  Switzerland
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Quote:
Originally Posted by sal87 View Post

So is there any way of simulating my box without building it just yet?


Sort of. Can you measure the drivers in the box/baffle, both on axis and off axis, without any xover filters? You could feed these data into a speaker CAD software, draw the xover schematic and simulate the system result. Vituix CAD comes to mind.
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