midrange/ passive crossover compatibility

[dale315 1]

I have a spare set of tweeters and crossovers from a 4" mb quart comp set. My question is, can I get any set of 6.5 midbass speakers and use the mb quart crossovers with it? Or are there certain factors that have to be looked at for one to be compatible with the other. I could just get a whole set of 6.5 comps but I remembered I had some extra parts and wanted to see if I can just get some midranges and use what I have.

[emh9009 199]

the Quart Xover is made specifically for the Quart's 6.5. Every driver is built differently and have different ranges of frequencies it can play. Unless you can match all the speaker's specs exactly, i say dont do it.

[jcarter1885 995]

Naw you cant put another midbass speaker on a passive crossover unless there specs are similar but they may be hard to find.

[emh9009 199]

of course you could use the tweeters and get the 6.5 you want and build your own crossover. (get the specs of the tweeter) or you could just get a nice amp with built in Xovers, OR a HU to do it more precisely.

[dale315 1]

Thanks for the comments. I knew it wasn't gonna be that easy.

[Notorious97200 339]

I think you can use the passive x-over for the tweeters, and the amp or the h u settings for the mids. But you will have to know what you're doing.

Do you really like these tweeters, or is it a budget issue ? Maybe you will have different opinions regarding your real goals for your system.

[smgreen20 3]

Xovers are all coils and caps. The speaker that is hooked to it could care less as long as the crossover freq and slope allow it to play in its range. Some xovers might be designed to tame an output, like the tweeter, because their tweeter might be to harsh, but other then that it doesn't matter. Some sort of tweeter protection might also be added to the mix. One thing you have to look at is the ohm of the speakers being used as that will change the xover point. People all the time, esp in the 90's, used MB Quart musicomp xovers for various drivers not of their own with 0 problems.

Edited May 10, 2010 by smgreen20

[Impious 1,476]

You need to consider more than just the impedance. You also need to consider how the new planned driver will perform with the the crossover slope and frequency of the passive. A crossover designed for a 4" midrange may have a higher crossover point or shallower slope than that designed for a 6.5" driver which would make performance lackluster. Or even if the drivers are the same diameter the new driver may roll off sooner or later than the original which will change the effective acoustic slope of the crossover which will change how the mid and tweeter integrate together. The impedance curve of the new driver may be different than the original driver which will change the crossover's behavior. You also need to consider if there are any additional "features" built into the crossover such as a zobel network, trap filters, etc which will be rendered useless and may actually hinder the new driver's performance. Or the new speaker may benefit from some of those features due to it's characteristics and since the filter network does not include them results could suffer.

So while it may technically "work", results very well may end up being very poor by using a driver on a crossover not specifically designed for that speaker. Generally not recommended to mix-n-match drivers and crossovers (and expect good results) unless you understand the variables involved, the actual design of the crossover itself and the behavior of the driver.

[smgreen20 3]

Which is why I stated

Some xovers might be designed to tame an output, like the tweeter, because their tweeter might be to harsh, but other then that it doesn't matter. Some sort of tweeter protection might also be added to the mix.

Xovers today are not all that complex as people make them out to be. Something is complex if we don't understand.

90% of the time when a company uses a xover, it's used for all of its sizes. 6 1/2", 5 1/4", 4". They look at it as it's the tweeter that remained constant so the xover point should too. It's just limited by how low the comp set will play after that determined by the driver.

I will also point out, as I didn't mention the first time around, that the speakers sensitivity will also play a big role, hence tweeter attenuation.

Edited May 12, 2010 by smgreen20

[///M5 2,833]

Which is why I stated

Some xovers might be designed to tame an output, like the tweeter, because their tweeter might be to harsh, but other then that it doesn't matter. Some sort of tweeter protection might also be added to the mix.

Xovers today are not all that complex as people make them out to be. Something is complex if we don't understand.

90% of the time when a company uses a xover, it's used for all of its sizes. 6 1/2", 5 1/4", 4". They look at it as it's the tweeter that remained constant so the xover point should too. It's just limited by how low the comp set will play after that determined by the driver.

I will also point out, as I didn't mention the first time around, that the speakers sensitivity will also play a big role, hence tweeter attenuation.

LOL, really good reason then to never buy from whatever company that is.

[Impious 1,476]

Which is why I stated

Some xovers might be designed to tame an output, like the tweeter, because their tweeter might be to harsh, but other then that it doesn't matter. Some sort of tweeter protection might also be added to the mix.

Xovers today are not all that complex as people make them out to be. Something is complex if we don't understand.

90% of the time when a company uses a xover, it's used for all of its sizes. 6 1/2", 5 1/4", 4". They look at it as it's the tweeter that remained constant so the xover point should too. It's just limited by how low the comp set will play after that determined by the driver.

I will also point out, as I didn't mention the first time around, that the speakers sensitivity will also play a big role, hence tweeter attenuation.

Reread what you quoted, then reread my post. Those two sentences that you quoted from yourself completely miss the boat, sorry. There's much more to it than simply tweeter attenuation/protection, which you then followed up with "other than that it doesn't matter". False. Much more than that does matter, as I briefly pointed out in my post.

Companies using the same passive crossover for every comp set within a given line are using horrible design practices, and are probably better off not being purchased in the first place.....much less using the already poorly designed crossover with a different mid. There is absolutely no rational logic based on the physics and acoustics involved that supports this statement; "as it's the tweeter that remained constant so the xover point should too".

As I said above.....using a different mid on a passive crossover may technically "work", but not recommended unless you fully understand all of the variables involved. Some people may get lucky and it might sound ok, good or even great. But unless it's actually analyzed before hand it's nothing other than shear dumb luck.

[///M5 2,833]

And that dumb luck never happens.

[smgreen20 3]

While I'm not an expert in Xover design, I do build my own and have done extensive research. Yea I'm still learning it all.

I'm also sorry to inform you that what I stated is true about using the same xover for multiple sets (in the same line) of various sized comps. PG, DYNAUDIO, RF, JL, MOREL... THEY ALL DO IT! You wouldn't buy speakers from them? I'll use Dynaudio for right now, their system 220/222 and 240/242 use the same xover, different mid sizes, but same xover- X250/X252.

When it comes down to it, it's a bunch of coils, caps, resistors and what ever tweet protection you want to use, Dynaudio uses a polysilicon resistor. It's all dependent on the values and what it all adds up to, which should be what the drivers impedance (not resistance) is for both drivers along w/there freq response.

[Impious 1,476]

While I'm not an expert in Xover design, I do build my own and have done extensive research. Yea I'm still learning it all.

I'm no expert either, but it sounds like you have a lot more learning to do.....

I'm also sorry to inform you that what I stated is true about using the same xover for multiple sets (in the same line) of various sized comps. PG, DYNAUDIO, RF, JL, MOREL... THEY ALL DO IT! You wouldn't buy speakers from them? I'll use Dynaudio for right now, their system 220/222 and 240/242 use the same xover, different mid sizes, but same xover- X250/X252.

I never said you were wrong....I said it wasn't a good practice and that your statement "as it's the tweeter that remained constant so the xover point should too" has no logical reasoning based on acoustics behind it. And no, actually, I wouldn't purchase any of those components. Morel & Dyn are very expensive for what you get, and PG/RF/JL don't offer products that fit my needs. For the most part, there are better options out there.

When it comes down to it, it's a bunch of coils, caps, resistors and what ever tweet protection you want to use,

You're right, it is just a "bunch of coils, caps and resistors", but how those caps, coils and resistors are used in the crossover is very important. To say "Some xovers might be designed to tame an output, like the tweeter, because their tweeter might be to harsh, but other then that it doesn't matter." is about as ignorant a statement as can be made. You obviously don't understand most aspects of designing a proper passive crossover, what all can be accomplished with a passive crossover, and all of the considerations or design difference in both the driver and crossover that will affect how different drivers will perform with a given passive crossover.

[smgreen20 3]

As I'm still learning, any links you have on the subject I would appreciate.

[Impious 1,476]

If you haven't read it already, LSDC is a good place to start;

"Loudspeaker Design Cookbook," 7th Ed. from Madisound