Do crossover frequencies affect timbre match

[The Dude]

I ask this as if one had a Lascala crossed at 500 or 600 hz, when used in between the Klipschorn crossed at 400hz. Both would have the same drivers but maybe different horns.

[Chris A]

Do crossover frequencies affect timbre match?

Typically, yes.

The reason why there will likely be a timbre shift if you change a speaker's crossover frequency is due to the different horn polars of the bass bins to the midrange, how both of these horns control their polars vs. frequency, and how that acoustic energy bounces off the nearby walls and other stuff, finally arriving at your ears.

If you are talking about only 100 Hz change in crossover frequency from stock crossover conditions you may not hear a lot of difference, assuming that the crossover is implemented well in both cases.

Changing out horns on Khorns or La Scalas is a very different proposiition, since this changes a lot of acoustics properties, and you can bet that timbre shift will occur.

Correcting for time misalignment of drivers/horns will have a very strong positive effect on the timbre of these speakers,

Chris

[The Dude]

Chris,

Maybe we should clear up what horns and drivers we are using, are you referring to the stock k77/k55/k400 setup.

The reason why there will likely be a timbre shift if you change a speaker's crossover frequency is due to the different horn polars of the bass bins to the midrange, how both of these horns control their polars vs. frequency, and how that acoustic energy bounces off the nearby walls and other stuff, finally arriving at your ears.

I take it this refers to all speaker structure, for instance the reference line tower speakers, going with any of the reference center.

[The Dude]

I don't know if what I am doing is best but I am experimenting for myself. What I was thinking of doing down the road is trying something along the lines of the K402 on the Khorns, and the K510 on the lascala, as 3 402s would be quite a bit. As for now I am trying some different horns, and trying to figure a good crossover point, if I should keep all the same or try a different one on the Lascala. I know active is probably the way to go but I can build 3 passive networks for the price of all the gear to go active.

[Chris A]

I take it this refers to all speaker structure, for instance the reference line tower speakers, going with any of the reference center.

I took a stab at answering what I thought was your question: clearly I missed the mark by your response.

To answer your immediate question/statement above: any change that you make to crossover filters, time alignment, drivers, horns, room placement, including nearby sound reflectors, or speaker cabinets will change their timbre. This was a surprise for me, and one that I was able to test out using an active crossover, absorbent panels in the room, and a similar and different center speaker type, for instance, Belle vs. Heresy [similar], or Heresy vs. RC-62 [very different]. The results were that any changes to any of these physical parameters changed the timbre of each speaker. Nowhere was this more dramatic for me than tri-amping my center Belle between two Jubs. Once I got the time alignment and crossovers under control, the Belle started to match its timbre with the flanking Jubs. Big time news...at least for me...

However, the apparent source width of the Belle is much smaller than the Jubs--but that's another subject.

Now, I assume that you are talking about the fact that the La Scala bass bin-midrange drivers are crossed at higher frequency than the Khorn, but their timbre is similar enough to each other so that you can use a La Scala between two Khorns. I attribute this to the fact that the midranges and tweeters for both speaker types are essentially identical AND that the polar characteristics of the La Scala midrange/bass bin at its crossover matches each other fairly closely, and the same for the Khorn midrange/bass bin polars at crossover. The fact that someone cared about polar matching within each speaker (midrange/bass bin) is a testiment to why they match timbre--along with their nearly identical midrange/tweeter horns/drivers. The polar performance of the K-400 midrange horn/K-55 driver apparently doesn't change strongly in the 400-600 Hz region (another topic for discussion), so it isn't very sensitive to changes in the crossover point. But if you change either speaker's midrange horn or driver out with something else having much different polar characteristics, that speaker's entire timbre will change.

I think of it like white balancing photos within Photoshop. You can match white balance, and do it using different cameras, lenses, and photodetector arrays (CCD chips), and look similar, but the hardware to produce these type photos might be very different from one another.

[The Dude]

I take it this refers to all speaker structure, for instance the reference line tower speakers, going with any of the reference center.

I took a stab at answering what I thought was your question: clearly I missed the mark by your response. .

No I think you answered it right, the reference thing was just something that popped in my mind. After I read your response and thought of my first question, I started thinking out loud. "How does Klipsch get away with crossing things over at different points". I have yet time to go through and read all of your last post, which I will do soon as I get home. I do want to thank you for taking the time to answer these question, I whish to understand this stuff better.. Unfortunately for myself and others I will have to ask some of the same questions.

[The Dude]

To answer your immediate question/statement above: any change that you make to crossover filters, time alignment, drivers, horns, room placement, including nearby sound reflectors, or speaker cabinets will change their timbre. This was a surprise for me, and one that I was able to test out using an active crossover, absorbent panels in the room, and a similar and different center speaker type, for instance, Belle vs. Heresy [similar], or Heresy vs. RC-62 [very different]. The results were that any changes to any of these physical parameters changed the timbre of each speaker. Nowhere was this more dramatic for me than tri-amping my center Belle between two Jubs. Once I got the time alignment and crossovers under control, the Belle started to match its timbre with the flanking Jubs. Big time news...at least for me...

I take it this is why active is a good way to go.

Now, I assume that you are talking about the fact that the La Scala bass bin-midrange drivers are crossed at higher frequency than the Khorn, but their timbre is similar enough to each other so that you can use a La Scala between two Khorns. I attribute this to the fact that the midranges and tweeters for both speaker types are essentially identical AND that the polar characteristics of the La Scala midrange/bass bin at its crossover matches each other fairly closely, and the same for the Khorn midrange/bass bin polars at crossover. The fact that someone cared about polar matching within each speaker (midrange/bass bin) is a testiment to why they match timbre--along with their nearly identical midrange/tweeter horns/drivers. The polar performance of the K-400 midrange horn/K-55 driver apparently doesn't change strongly in the 400-600 Hz region (another topic for discussion), so it isn't very sensitive to changes in the crossover point. But if you change either speaker's midrange horn or driver out with something else having much different polar characteristics, that speaker's entire timbre will change

1: If I am using the same driver on all three, lets say the k-69-a, 2: If I am using the same horn or horns with the same polar response, 3: I don't change the crossovers to much 100-200 hz. I should be ok or it should be easier to eq to get a better timbre match once I do go active.

[The Dude]

Chris if you get the chance could you explain or point me to a thread that explains 90x40 or 60x40 degree horns. The reason I ask I was looking at some different horns such as the JBL 2380 or the JBL 2386 which the JBL 2386 is a 40x20 degree horn if this can be crossed at 400 hz what kind of issue would it cause being a 40x20.

[DavidF]

The xover is usually the last significant part of the design

process as the designer “voices” the system. An experienced designer knows how

to lay out a crossover design pretty much based upon a sense of what will work.

Then some empirical testing and measuring is needed to further refine the

filter. This is because using actual drivers with their variance in impedance

and response at any given test point will not fit the theoretically perfect

design based upon a fixed impedance and frequency response. Finally the designer

will fine tune the filter components using either a desired measurement criteria

or simply by listening. You can see that if even a small tweak in the filter or

a driver substitution can upset the finely tuned design.

So if you are considering changes, and major changes at

that, will it change the timber of the system response? Absolutely. Most times

in a negative way. My comments are not to discourage your system tweaking but

more to caution against thinking that simply by swapping speaker system

components you could expect such change to be an “upgrade”.

[Don Richard]

It's a combination of the electrical crossover and the frequency response of the drivers. Together they define an acoustic crossover which will certainly be different from the electrical crossover in terms of frequency and slope. And then there is the matter of phase and type of filter, such as Butterworth, Bessel, and Linkwitz-Riley. Everything has to work together for proper performance.

Crossover design is not a trivial matter. Buying a generic crossover that was designed without consideration to the drivers hooked to it most often results in sonic garbage.