Kustom MT15/Gollehon MR90 crossover help

[Zwiller]

Need some help getting these fired up: http://www.diyaudio.com/forums/subwoofers/275639-id-mid-horn.html
Kustom MT15 with EV T35 and EV 1824. Gollehon MR90 crossovers were added at some point. Both cabs are DOA but all but 1 T35 drivers are OK. No continuity through the white part on the lower left. Not sure what this even is, all the markings are serial/mfr data best I can tell. No markings on brown (cap?) or inductor either. From my noob crossover knowledge it appears the large cap to far left (black) is 77uF and good for 500hz HP? (due to 2 T35s @ 8ohm/first order) and the curcuit on the 1824 might be HP for T35’s (cap is 4.7uF/first order?) so maybe I can bypass the Gollehon altogether at least for now? That said, I would like to get the MR90 fired up… Could the white part be a fuse? Lastly, gonna run those mid horns with EVM 15L's. Do I need to LP? 2.5mH inductor? For now I want to keep it passive...

Any direction appreciated.

EV T35
https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=6&cad=rja&uact=8&ved=0ahUKEwi50rqPq9nKAhUCPT4KHWf5BcUQFggqMAU&url=http%3A%2F%2Fwww.electrovoice.com%2Fdownloadfile.php%3Fi%3D971159&usg=AFQjCNFEQVYsapYpVd3IZkS1arFbJeZC6Q&sig2=2xs3GQJzW4e04q-JPc1ZFQ&bvm=bv.113034660,d.cWw

EV 1824
https://www.google.com/url?sa=t&rct...k67cEBbcDGL_6LHIEU1Sqg&bvm=bv.113034660,d.cWw

EVM 15L
https://www.google.com/url?sa=t&rct...ftQH8LwhqX4yejEZA&sig2=NMkWyf5KyENRnm8S3c_6-Q

 

[weltersys]

Need some help getting these fired up: http://www.diyaudio.com/forums/subwoofers/275639-id-mid-horn.html
Kustom MT15 with EV T35 and EV 1824. Gollehon MR90 crossovers were added at some point. Both cabs are DOA but all but 1 T35 drivers are OK. No continuity through the white part on the lower left. Not sure what this even is, all the markings are serial/mfr data best I can tell. No markings on brown (cap?) or inductor either. From my noob crossover knowledge it appears the large cap to far left (black) is 77uF and good for 500hz HP? (due to 2 T35s @ 8ohm/first order) and the curcuit on the 1824 might be HP for T35’s (cap is 4.7uF/first order?) so maybe I can bypass the Gollehon altogether at least for now? That said, I would like to get the MR90 fired up… Could the white part be a fuse? Lastly, gonna run those mid horns with EVM 15L's. Do I need to LP? 2.5mH inductor? For now I want to keep it passive...

Any direction appreciated.

Sam,

The brown part is probably a wire wound resistor.
Don't know what the white part is.
The 77uF cap was probably just used as DC protection, and is probably dried out.

If you want to re-use the components you will need to measure them to see if they are still working properly.

I'd suggest copying the crossovers used by the Klipsch Heresy II speakers that use similar components, but that still won't be right for your mid horns or 15", but closer than the jive pile you have now.

With a steep filter, one T-35 per side will get plenty loud for home use, and are more sensitive than the 15L.

Art

 

[Zwiller]

Thanks Art, especially for clarifying the Heresy II model. The Klipsch XO are interesting with that transformer. Looks like the Heresy is the type E XO and the HII being the E2. Is there a way around needing the transformer?

 

[Zwiller]

Think I made a little sense of the old XO circuit. Tweeter HP circuit is on mid horn and appears to be first order near 4kH (4.7uF) with 3.3ohm resistor for attenuation. The midhorn circuit is the gollehon XO. I had this backwards in my mind. Circuit appears to be 2nd order @ 550hz (43uF measured prolly a 47uf) but cannot measure inductor to be sure. I disconnected the "white thing" and it was a cap and within spec. Little did I know that caps do not pass continuity... The brown thing is a resistor and in spec at 4ohms. Thinking I will wire this up removing resistor to run one tweeter and reversing polarity as 2nd order. Leave gollehon XO alone with resistor in circuit as mid horn is 2db hotter (107db) than tweeter (105db) on paper. Woofer is 105db average per hornresp sim. Will remove the 77uF cap, it is way off too... Then I need LP to 15". Looks like 2.0mH + 47uF gets me 2nd order LP from 650hz. If this fires up and get me near anything doable I might be confident enough to order the parts for the LP filter and if that works I might tackle the Klipsch design. Starting to get dangerous with XO circuits now... Still a little grey on impedance with resistors when using online calcs. IE - 8ohm driver and 3.3ohm resistor. 4.7 > 5 ohms right?

 

[weltersys]

Tweeter HP circuit is on mid horn and appears to be first order near 4kH (4.7uF) with 3.3ohm resistor for attenuation. Still a little grey on impedance with resistors when using online calcs. IE - 8ohm driver and 3.3ohm resistor. 4.7 > 5 ohms right?

The reason the tweeter burned out is a first order crossover is not steep enough to protect the fragile little 5 watt voice coil.
An "8 ohm" driver is 8 ohms only at one frequency, which is why designing passive crossovers is so difficult, a particular coil cap combination may behave completely differently than what a calculation based on a fixed impedance would suggest.

You really need to measure the driver's raw frequency response and compare it to what the crossover is doing, and adjust components accordingly to avoid costly mistakes and poor sounding results, of which I have made plenty...

Art

 

[Zwiller]

Makes sense about the tweeter... The Klipsch incorporates a 3rd order for it. I can't seem to make heads or tails of the Type E circuit. Must be some custom Klipsch magic built into it. No doubt taking measurements will be the best way but right now just going for rock and roll and learning experience. Heck, I will be happy if they fire up at all since this is my first foray in passive XO.

 

[weltersys]

Makes sense about the tweeter... The Klipsch incorporates a 3rd order for it. I can't seem to make heads or tails of the Type E circuit. Must be some custom Klipsch magic built into it. No doubt taking measurements will be the best way but right now just going for rock and roll and learning experience. Heck, I will be happy if they fire up at all since this is my first foray in passive XO.

Yeah, passive crossovers can be hard to figure out, and really the only part of the Klipsch that would translate well to your application would be the HF portion.

My "rock and roll" introduction to passive crossovers cost me about $600 in replacing diaphragms that blew on the first show, a lot more than a measurement mic (around $50 and up) for the free REW software now available cost.

If you have not already, read this for some good insight:
http://www.diyaudio.com/forums/mult...designing-crossovers-without-measurement.html

Art

 

[Zwiller]

Started thinking about this and maybe a better direction would be to clone the EV XO circuits. X8 and X36. https://community.klipsch.com/index.php?/topic/72382-electro-voice-x36-datasheet-attached/ I suppose some measurement gear is in order too if I continue to tinker. In a similar note, I have dilemma. I was brought in to consult (as an old band guy) for a new PA system of local high school. Mostly just looking power ratings etc. My understanding EV rep did the engineering. Recently attended a function and it sounded very out of phase. Would love to bugger around and get to the bottom of it and curious what tools would be necessary to debug. I swear it sounded so out of phase like if I reverse a terminal it will come alive. Maybe a kid swapped a cable or maybe the cabs distances are off.

 

[weltersys]

Recently attended a function and it sounded very out of phase. Would love to bugger around and get to the bottom of it and curious what tools would be necessary to debug.

Sam,

You can see phase, impulse and frequency response with REW, which runs on both windows and current Mac OS. You will also need a measurement mic and an audio interface to your computer. If the system is flown, you probably will need a very long boom stand to get near field measurements.

Since you are not familiar with measurement, expect to spend many (many) hours learning how in the comfort of your home before attempting to "debug" a system, (or build crossovers).

Art

 

[Zwiller]

Main reason I am putting off REW is the learning curve. Costs are reasonable. Yep, system is flown... Truly a professional's job. I just want to identify the need to get one. I should be able to get behind the system tho. First thing I going to figure out is if it stereo and try some panning at least if something obvious shakes out. Anything blatantly off? Speakers are in pairs back to back.

 

[weltersys]

Anything blatantly off? Speakers are in pairs back to back.

The picture is too low resolution to see any detail of the cabinets, and the angle is such that it is hard to determine if they are covering the listening area without excessive inter cabinet overlap, so can't say whether anything is "blatantly off". The cabinets are likely a two way, horn along side of a cone driver, which puts the off axis lobe/dips in the horizontal plane. Considering the width of the coverage area compared to the depth, a vertical orientation of the same cabinets (possibly requiring rotating the horn, if that is an option) would likely give better sonic results, but would hang down further, compromising aesthetics, and create a more likely basketball target.

Art

 

[Zwiller]

I will get back us on topic... So, for some odd reason I have been really fired up about getting these things playing. Considered some "vintage" EV XO on ebay but worried they are out of spec due to age. Searched ebay for a few hours for some chinese XO but none in at the XO points I wanted. Was going to harvest some XO in some old JBL 3 ways laying arpund but XO points were way off. Then I thought, maybe these were not correctly wired in first place... Thanks to my new found knowledge of XO I got them going! They were like I described in post 4. I needed to make a few changes with soldering iron but happy to say they are running. Loaded up the EVM 15L in the bass horns and got them going too. The bass horns were overpowering the tops so I thought maybe remove the resistors in the XO to bring them up and that worked immensely! Even then I need to drop the bass down -3db to get it balanced to my ears. Took your advice and mounted cab vertically helped too, looks sorta sexy .

I have really taking a liking to the mid horn but not enamored with the T35. Sorta metallic and has less top end to my ears. Started looking for mythical baby butt checks T350 but they are overpriced IMO. Happened to find a post of yours about the APT200 and am considering swapping it. Then maybe a LP inductor for the bass cabs but they don't seem as bad as I thought they would running full range. Overall a happy camper!

 

[weltersys]

Then maybe a LP inductor for the bass cabs but they don't seem as bad as I thought they would running full range. Overall a happy camper!

The 15L definitely need a crossover, once they are crossed properly they won't outrun the mid/high.

As well as a proper crossover, the T-35 may require shims (or proper diaphragm alignment) inside to get them sounding right.

The APT drivers I have used have large deviations between them, but have good sensitivity and are a lot more robust than T-35.