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#422967 - 01/31/17 05:37 AM Crossover design
Serenity_then Offline
connoisseur

Registered: 03/28/14
Posts: 1572
Loc: PEI, Canada
Does anyone know how critical it is to maintain the exact components in a crossover design?

I ask because I am about to build some speakers and will likely sustitute higher tolerance parts than were spec'd in the original design. ie. inductors with lower resistance. Resistors with lower inductance etc. than designer spec'd parts.

I have an email into the designer as well but thought I would ask the void for input.


Edited by Serenity_Now (01/31/17 05:38 AM)
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#422982 - 01/31/17 04:48 PM Re: Crossover design [Re: Serenity_then]
alan Offline

connoisseur

Registered: 01/29/02
Posts: 3267
Loc: Toronto/New York/parry Sound
Hi Serenity,

Unless you have a technical electronics or engineering degree and the electronic gear to plug in different component values and graph the changes in frequency response and crossover slopes, it's impossible to estimate what effects the substitution of different components will have in a particular crossover design.

I recall watching Ian test different values of crossover components in tweaking the design of an Axiom speaker, and subtle changes in the component values gave the speaker an entirely different midrange response when the speaker was measured and then tested in double-blind listening tests.

The speaker might have been the early M80ti, whose midrange response I was highly critical of (edgy and sibilant on female vocals and brass instruments) and wanted him to change, which he did.

Good luck (and you'll need it) on the home-built speaker design.

Alan
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#422991 - 02/01/17 05:19 AM Re: Crossover design [Re: Serenity_then]
Serenity_then Offline
connoisseur

Registered: 03/28/14
Posts: 1572
Loc: PEI, Canada
Thanks! smile

I'm not going to stray from the prescribed values, just go from 5% to 1 or 2% parts and larger AWG size on the inductors. After some poking around I see that parts costs escalate quickly, so I'm not going crazy with Mundorf Maximizer Ultimate Sunshine.... laugh

Solen Fast Caps (PB, SB in tweeter CCT), Erse Inductors 16awg, Mills Resistors in parallel to double power handling and further tighten tolerances. Pretty much defacto parts express stuff for mid to higher range builds. High value for $ stuff. Won't be cheap, but wont be silly either. Or is it..... Total estimated cost for 3 towers $529 before shipping. Yikes!
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Trevor. Cold turkey. Thanks guys. Cheers.

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#422992 - 02/01/17 05:47 AM Re: Crossover design [Re: Serenity_then]
Mojo Offline
connoisseur

Registered: 01/21/07
Posts: 4979
The benefits of tighter component tolerances increase with filter order. A third order filter would benefit greatly but a first order won't.

My advice is to build the kit. Once you've done that, then you can experiment. Try to get the ideal parts list from the designer. The ideal parts list comes from calculated values. The first thing to do is wind your own inductors. These are the most non-ideal component. Then switch to non electrolytic caps.

Alan is right in that a crossover is complex business. I know because I've been involved in the design of passive and active filters - not for loudspeakers. The passive crossover for a loudspeaker incolves a lot of mental masturbation particularly for second and higher orders. Controlling the voice coil via passive means when it's impedance changes as a function of temperature, altitude and input power is darned near impossible.

Hence why active crossovers are the only way to go and that's where the LFR needs to go next.

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#422993 - 02/01/17 06:30 AM Re: Crossover design [Re: Serenity_then]
Serenity_then Offline
connoisseur

Registered: 03/28/14
Posts: 1572
Loc: PEI, Canada
My understanding with active is you need to handle each transducer seperately, including amplification. Too expensive for a 3 channel setup with 3 way towers. I am building external crossover boxes so the driver leads are available for further adventures. Options. smile
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Trevor. Cold turkey. Thanks guys. Cheers.

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#422994 - 02/01/17 06:44 AM Re: Crossover design [Re: Serenity_then]
Mojo Offline
connoisseur

Registered: 01/21/07
Posts: 4979
Separate amps indeed but it looks like you are all set for that smile.

External crossovers also eliminate any concern from magnetic coupling from the drivers including modulation from enclosure vibrations.

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#422995 - 02/01/17 06:46 AM Re: Crossover design [Re: Serenity_then]
Mojo Offline
connoisseur

Registered: 01/21/07
Posts: 4979
I really butchered the spelling on my second last post. Phones and larger fingers don't work well together.

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#422996 - 02/01/17 08:41 AM Re: Crossover design [Re: Serenity_then]
Adrian Offline
axiomite

Registered: 12/27/08
Posts: 6895
Loc: It's all about the location.
Over $500 for crossover parts?

You can get an excellent digital crossover for far less than that. You'll need some amps though $$.
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Half of communication is listening. You can't listen with your mouth.

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#422998 - 02/01/17 09:07 AM Re: Crossover design [Re: Serenity_then]
Mojo Offline
connoisseur

Registered: 01/21/07
Posts: 4979
Where do you get the digital X-over from?

Interestingly enough my Onk has two separate outputs per channel for the front. One of the outputs is for bass and mid-range and the other is for the tweeter. You can configure your own X-over in the setup. I've never tried it but have always wondered how well it works.

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#422999 - 02/01/17 10:02 AM Re: Crossover design [Re: Serenity_then]
Adrian Offline
axiomite

Registered: 12/27/08
Posts: 6895
Loc: It's all about the location.
MiniDSP, Behringer DCX2496, I'm not sure if BBE still makes one or not. The MiniDSP is supposed to be a really good unit.
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Half of communication is listening. You can't listen with your mouth.

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