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Is it OK for a three-way designed speaker to out put the same tone through two drivers?

NewbieAudiophileExpert

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Say for example i have a three way loud-speaker with a separate tweeter, mid, and bass drivers and i play a 450HZ tone though the generator on google, and it's being output from both the bass and mid driver, would this indicate a flaw (or an opportunity to improve) with the cross over design?

Theoretically the best designed speaker would only play a certain frequency range from a certain driver - i.e. tweeter, 7.5k-20k; mid, 7.5k-350; bass, 350hz and below.

Although this would be hard(er) to achieve with a tradition, passive crossover design, is it something that certain models have?
 
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mdsimon2

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Say for example i have a three way loud-speaker with a separate tweeter, mid, and bass drivers and i play a 450HZ tone though the generator on google, and it's being output from both the bass and mid driver, would this indicate a flaw (or an opportunity to improve) with the cross over design?

Theoretically the best designed speaker would only play a certain frequency range from a certain driver - i.e. tweeter, 7.5k-20k; mid, 7.5k-250; bass, 250hz and below.

A crossover is not a brick wall. What are the crossover frequencies and slopes? If 450 Hz is reasonably close to the crossover frequency you would expect sound from multiple drivers. I personally have found that I prefer shallower crossover slopes (2nd order), YMMV.

Michael
 

Kal Rubinson

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Crossovers are not brick-walls at a defined frequency. The output from the woofer will be rolled off gradually above the defined frequency and the midrange will be rolled off gradually below that frequency. The rate with which they roll off is determined by crossover configuration and each will have significant output beyond the crossover frequency.
 

DVDdoug

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7.5k-20k; mid, 7.5k-350; bass, 350hz and below.
Or maybe the crossover happens at 450Hz... ;) That's up to the speaker designer.

At the crossover frequency the output should be equal from both drivers and 3dB down so ideally-theoretically the frequency response is (approximately) flat. Beyond that, most passive crossovers have a slope of 12dB per octave
 
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NewbieAudiophileExpert

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Hey all thanks for the responses that clarified this issue and helped me understand how passive crossovers function.

Like most things in life this isn't so black and white - either way it was good to test this hypothesis of brickwall cross over frequencies.

Seems kinda silly in hindsight though.

What's the specific speaker?
Wharfwdale crystal 4.3s
 

Chrispy

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FWIW a visualization of a crossover point (with specific slopes) to help out perhaps?
 

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NewbieAudiophileExpert

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FWIW a visualization of a crossover point (with specific slopes) to help out perhaps?
Ahh yeah, it makes even more sense now that you've provided a visual diagram to help demonstrate the curve - of course, like most things in life it's not black and white and is on a spectrum instead... perhaps it's better than way?

(I wonder if replacing the crossover components to air core inductors and film caps would confer any benefit?
 

Chrispy

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Ahh yeah, it makes even more sense now that you've provided a visual diagram to help demonstrate the curve - of course, like most things in life it's not black and white and is on a spectrum instead... perhaps it's better than way?

(I wonder if replacing the crossover components to air core inductors and film caps would confer any benefit?
Doubtful....is something out of spec or have you been reading silly audiophilia stuff?
 
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Doubtful....is something out of spec or have you been reading silly audiophilia stuff?
No, not at all - I quite like my speakers, even though they're probably the cheapest Wharfedale has to offer... i feel that the speaker design is quite cool, with the tweeter and mid driver sealed, whilst the woofer is in a ported enclosure of it's own, making it a 'built in subwoofer', so to speak. I'd say it's a subwoofer, because the 5 inch mid could easily reproduce down to 80Hz frequency.

Wonder if there is any software that would help me identify any flaws with the speaker design? REW perhaps?
 

Chrispy

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No, not at all - I quite like my speakers, even though they're probably the cheapest Wharfedale has to offer... i feel that the speaker design is quite cool, with the tweeter and mid driver sealed, whilst the woofer is in a ported enclosure of it's own, making it a 'built in subwoofer', so to speak. I'd say it's a subwoofer, because the 5 inch mid could easily reproduce down to 80Hz frequency.

Wonder if there is any software that would help me identify any flaws with the speaker design? REW perhaps?
If you have the t/s parameters perhaps you could design your own box or proof the one it's in to an extent. If you don't have the t/s parameters you could maybe measure them on your own with something like Dayton's DATS system (combined with their Omnimic kit could do well for you perhaps). Box software like winisd could work for box designs.

The Wharfdale if the lowest in their line is basically just a limited speaker and perhaps not worth spending more time/effort on and better to just move on or do something different or start with a whole different design/driver set if you want to diy something....and maybe just go active crossover.
 
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NewbieAudiophileExpert

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If you have the t/s parameters perhaps you could design your own box or proof the one it's in to an extent. If you don't have the t/s parameters you could maybe measure them on your own with something like Dayton's DATS system (combined with their Omnimic kit could do well for you perhaps). Box software like winisd could work for box designs.

The Wharfdale if the lowest in their line is basically just a limited speaker and perhaps not worth spending more time/effort on and better to just move on or do something different or start with a whole different design/driver set if you want to diy something....and maybe just go active crossover.
Yeah i think that you're right and that it might not be a valuable investment of time, especially considering that there's nothing really 'wrong' with them...

I know that they are the 'lowest' range in wharfedale, and for the price I'd paid, it was not getting any better.

Joe and Tell on youtube has compared them to some ELAC debut F5.2 which are in a similar price range, and he personally ranked them higher overall, so there's that.

Though i don't doubt that the Evo or new Elysium line would smoke them outta the water.

As a bit of background I'd bought them for $500 AUD in 'like new' condition, whilst even moderately priced 'budget' bookshelves (SVS, Klipsch RP, KEF Q150) cost anywhere from $700-1000 here.. budget towers are RRP $1700-2500 AUD.
 

Chrispy

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Yeah i think that you're right and that it might not be a valuable investment of time, especially considering that there's nothing really 'wrong' with them...

I know that they are the 'lowest' range in wharfedale, and for the price I'd paid, it was not getting any better.

Joe and Tell on youtube has compared them to some ELAC debut F5.2 which are in a similar price range, and he personally ranked them higher overall, so there's that.

Though i don't doubt that the Evo or new Elysium line would smoke them outta the water.

As a bit of background I'd bought them for $500 AUD in 'like new' condition, whilst even moderately priced 'budget' bookshelves (SVS, Klipsch RP, KEF Q150) cost anywhere from $700-1000 here.. budget towers are RRP $1700-2500 AUD.
Yeah from what I've seen over the years you have limited options and high prices overall down under. Making lateral moves isn't all that productive IMO, better to wait/save for significant improvements. Are you using sub(s)?
 
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NewbieAudiophileExpert

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Yeah from what I've seen over the years you have limited options and high prices overall down under. Making lateral moves isn't all that productive IMO, better to wait/save for significant improvements. Are you using sub(s)?
Yeah that's exactly my point, for the amount of money I'd spent, I was not getting better value - besides, i find nothing 'wrong' with the sound, if you catch my drift.. even the cheapest wharfedales are better than the 'home theatre in a box' speaker solutions that cost roughly the same as what I'd spent.

Even with the Klipsch RP series or the KEFS, sure they may sound better to some, but spending more than than 1.5K for home theatre and audio listening speakers was not on my agenda.

Maybe when i have a spare million LOL.. although might get a porsche before that.
 

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Although this would be hard(er) to achieve with a tradition, passive crossover design, is it something that certain models have?
Yes, "some" speakers are like that - drivers that emit no sound outside intended pass-band. Though I would not call the technology behind this traditional.

This can be implemented both in passive and active digital filters. Whether this is a benefit depends on the speaker design, sometimes a quite large overlap is intentional.
 
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Yes, "some" speakers are like that - drivers that emit no sound outside intended pass-band. Though I would not call the technology behind this traditional.

This can be implemented both in passive and active digital filters. Whether this is a benefit depends on the speaker design, sometimes a quite large overlap is intentional.
Yeah, it makes sense now that i think about it - the only time you'd want a really specific crossover frequency or a smaller overlap as you call it, would be in a 4 (or 5) way design... like for example in a design where you'd want as little sub-bass as possible going towards the mid or woofer, and taking up 'bandwidth' or whatever it's called.
 

Andysu

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i just let the video say what i want to say about this topic
 

gnarly

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Hey all thanks for the responses that clarified this issue and helped me understand how passive crossovers function.

Like most things in life this isn't so black and white - either way it was good to test this hypothesis of brickwall cross over frequencies.

Seems kinda silly in hindsight though.
Not silly at all :)
In fact, more and more advanced active speaker designs are beginning to use crossovers that have very steep slopes, even to the point of using brickwalls.

Steep slopes or brickwalls aren't at all pragmatic with passive crossovers or active analog crossovers, due to both their complexity to implement and the sonic degradation that occurs with their use. (excessive phase rotation is the sonic issue)

However, DSP FIR filter crossovers, can easily implement steep/slopes, and have no sonic degradation when properly implemented. (FIR crossovers can be constructed without phase rotation. Doing that does create a fixed constant delay, just like increased listening distance from speaker, that may or may not be an issue)

Off-axis lobing problems from two drivers sharing the same frequency range in the crossover region can be substantially reduced with steep/brickwalls.

Requires an active multi-way design ...best candidates are self-powered speakers, or externally amplified speakers where speaker comes with a processor (& often amps too) package.



Like you say...not so black and white...at all ! :)
 

voodooless

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Not silly at all :)
It is indeed not silly at all. The best thing is that you can visualize what happens. Have a look at a ripple tank simulator: http://www.falstad.com/ripple/ Just select one of the multi-source examples and you'll see what it does. You'll get interference patterns. What those patterns look like is dependent on the wavelength of the sound (frequency), and the distance of the drivers. You'll see that if you lower the "source frequency", the waves start adding up, and you'll get uniform output. That is exactly what should happen in the crossover region. Past this region begin the issues: if the output is not attenuated enough, it can still be destructive and lead to lobing. This happens especially where woofers have a resonance that is not properly controlled or filtered away. Usually filtering this away is better than using a higher slope.

In fact, more and more advanced active speaker designs are beginning to use crossovers that have very steep slopes, even to the point of using brickwalls.

Steep slopes or brickwalls aren't at all pragmatic with passive crossovers or active analog crossovers, due to both their complexity to implement and the sonic degradation that occurs with their use. (excessive phase rotation is the sonic issue)

However, DSP FIR filter crossovers, can easily implement steep/slopes, and have no sonic degradation when properly implemented. (FIR crossovers can be constructed without phase rotation. Doing that does create a fixed constant delay, just like increased listening distance from speaker, that may or may not be an issue)
These things also have issues. You'll need just about perfect directivity matching to make this work. In a normal less steep slope, directivity will slowly be matched. With brick wall filters you can get a sudden step. Extra care has to be taken as well to create filters with little rining. This might be audible in some cases.
 

abdo123

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Or maybe the crossover happens at 450Hz... ;) That's up to the speaker designer.

At the crossover frequency the output should be equal from both drivers and 3dB down so ideally-theoretically the frequency response is (approximately) flat. Beyond that, most passive crossovers have a slope of 12dB per octave

I think you mean 6dB there.
 
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