Where to crossover mid drivers

[hulminator]

I've been looking for a mid driver that I can crossover a little higher than your conventional 2-3khz. Taking a look at http://www.scan-speak.dk/datasheet/pdf/12m-4631g00.pdf http://www.tymphany.com/files/NE123W-08-HS Rev1_0.pdf how high would I be able to take these If I want to restrict myself to no more than second order filters (maybe third order if I have to). It seems the damping slices in the cone of the SS would allow less restrictive filtering, but I'm a beginner so could be wrong.

 

[Swerd]

I've been looking for a mid driver that I can crossover a little higher than your conventional 2-3khz. Taking a look at http://www.scan-speak.dk/datasheet/pdf/12m-4631g00.pdf http://www.tymphany.com/files/NE123W-08-HS Rev1_0.pdf how high would I be able to take these If I want to restrict myself to no more than second order filters (maybe third order if I have to). It seems the damping slices in the cone of the SS would allow less restrictive filtering, but I'm a beginner so could be wrong.

With a 2nd order crossover to a tweeter, you should plan on using a midrange and tweeter able to smoothly respond within 2 octaves of the crossover point, without great loss in off axis response. Looking at the frequency response curve for that 12M Revelator, I'd guess you might be able to go as high as 2 kHz. Two octaves higher, would be 8 kHz. Break up seems to begin at 6 kHz, but I don't know if noise would be audible.

At 5 kHz, it doesn't look like it is yet in breakup. At 4 kHz the off angle response (what angle is the green line?) is within 3 dB of the black line (on axis). That would be good for off axis response and the resulting imaging. Above 5 kHz it drops to below 5 dB below the black line, which is lower than I would want for off axis response.

You might be able to crossover higher than 3 kHz with a higher order crossover. A 4th order crossover allows you to look at response within one octave of the crossover point.

 

[GranteedEV]

As far as pricey 4" mids go, i would be looking at two options personally: Scanspeak 12MU Illuminator and Accuton C90-6-79

Now the problem with high crossover points is that you edge near cone resonances while the cone becomes increasingly directive. The 2nd order slopes may work, but you should be prepared to go 4th order too. Even if breakups appear mild on the frequency response graph, you should assume that the driver is not going to be contributing its best at that bandwidth.

 

[fuzz092888]

I've been looking for a mid driver that I can crossover a little higher than your conventional 2-3khz. Taking a look at http://www.scan-speak.dk/datasheet/pdf/12m-4631g00.pdf http://www.tymphany.com/files/NE123W-08-HS Rev1_0.pdf how high would I be able to take these If I want to restrict myself to no more than second order filters (maybe third order if I have to). It seems the damping slices in the cone of the SS would allow less restrictive filtering, but I'm a beginner so could be wrong.

Many guys active in the DIY community recommend you don't go into any project with preconceived notions about slopes and filters and that you should follow the drivers. Have a general area you want to crossover, find drivers that look like they can crossover somewhere in the area you are looking, get the drivers, pull the T/S parameters directly from the drivers and start modeling from there. You don't want to say I definitely want this or that and then spend a ton of time trying to force the drivers into a 2nd order when a 4th would have been much simpler and easier.

Also, listen to Swerd.

 

[TLS Guy]

I've been looking for a mid driver that I can crossover a little higher than your conventional 2-3khz. Taking a look at http://www.scan-speak.dk/datasheet/pdf/12m-4631g00.pdf http://www.tymphany.com/files/NE123W-08-HS Rev1_0.pdf how high would I be able to take these If I want to restrict myself to no more than second order filters (maybe third order if I have to). It seems the damping slices in the cone of the SS would allow less restrictive filtering, but I'm a beginner so could be wrong.

The first item of business is to select drivers for which a reasonable crossover can be designed.

The acoustic response of the drivers will tell you what slopes and Eq are required. The drivers roll off sum with the electrical roll off of the filters.

You will need a modelling program.

As far as bandwidth of mid range drivers is concerned, the is a dearth of decent ones. This makes two way designs much easier.

As far as crossing over above 3 kHz it pretty much means getting the ATC mid which their pro agents in Vegas will sell you if you twist their arm, or finding pair of vintage Dynaudio D76 domes on eBay, or using an Acutron, mid. If you use the latter, make sure you design the crossover correctly, or the ceramic cone will shatter.

Crossover design is the most difficult part of any speaker project and you need to get experience.

Three ways are far tougher than two ways. For a first project starting with a two way is strongly encouraged.

If you want a three way, I would not spend a fortune on drivers the first time round.

For something cost effective this driver has a lot to recommend it.

I would use band pass crossover points of 350 Hz and 2.5 to 3 kHz. No higher than 3 kHz.

The SEAS Exel drivers make good midrange units, but below 3 KHz on the top end. They are hard to work with and I strongly advise against using these for a first project.

In addition in my view it is preferable to make the lower crossover point active and bi-amp. In the lower frequencies active filters are far preferable to passive ones from my experience.

 

[hulminator]

This ATC driver?

ATC Midrange Units

 

[TLS Guy]

This ATC driver?

ATC Midrange Units

Yes, that one.

 

[lsiberian]

If you want to construct a pair of 3-ways I recommend using a pair of MiniDSPs with a pair of 4 channel chip amps.

For my 3 way I used a Dayton Dome Midrange. 500hz to 5khz gives you a very nice band. Plus it's enclosed so you only need one enclosure chamber for the bottoms.