Hello all. I need some technical advice, and I know I'm in the right place for that.
I own a set of Mission 765is that I bought in the early 90s. I love them, but the highs are not up to snuff for todays music, or maybe I'm getting a little deaf. Today, I bought a used pair of big Heils with the original crossovers from ESS AMT monitor speakers. I am told they are all in mint condition, and I'll know soon enough when I receive them. I had a pair of ESS speakers in the 80's and I loved the mids and highs they produced. I am hoping to meld the smooth bass and mid-bass from the Missions,with the midrange and treble of the Heils.
My question is, what is the best way to to go about hooking them up to my Missions? I am driving my Missions with a Adcom 5802 amp. I also have a McIntosh 2300 I could use as well, but currently it is driving my surrounds. Both amps can drive down to 2 ohms.
Should I leave the Missions as is, and run another wire from my amp to the ESS crossovers, and then to the Heils, or should I use the ESS crossover to replace the crossover that come with the Missions, and disconnect the Mission tweeter? I am not sure how this would effect the impedance. The Missions use a two way design, with two 8" drivers and a dome tweeter.
Thank-you in advance,
Rick
I own a set of Mission 765is that I bought in the early 90s. I love them, but the highs are not up to snuff for todays music, or maybe I'm getting a little deaf. Today, I bought a used pair of big Heils with the original crossovers from ESS AMT monitor speakers. I am told they are all in mint condition, and I'll know soon enough when I receive them. I had a pair of ESS speakers in the 80's and I loved the mids and highs they produced. I am hoping to meld the smooth bass and mid-bass from the Missions,with the midrange and treble of the Heils.
My question is, what is the best way to to go about hooking them up to my Missions? I am driving my Missions with a Adcom 5802 amp. I also have a McIntosh 2300 I could use as well, but currently it is driving my surrounds. Both amps can drive down to 2 ohms.
Should I leave the Missions as is, and run another wire from my amp to the ESS crossovers, and then to the Heils, or should I use the ESS crossover to replace the crossover that come with the Missions, and disconnect the Mission tweeter? I am not sure how this would effect the impedance. The Missions use a two way design, with two 8" drivers and a dome tweeter.
Thank-you in advance,
Rick
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Short of building new crossovers, I would suggest you start by disconnecting your mission tweeters, and running the heils from a separate amp. This will help you to take care of the difference in level. Although I have neither of these speakers, I believe the heils are sensitive.
Secondly. you'll need to adjust at least one of the crossovers to meet up with the other, if they don't just work straight off. It would be tempting to leave the heil crossover alone and adjust the mission woofers but this is something you may need to work out on your own. Do you have the mission crossover schematic or a photo?
Secondly. you'll need to adjust at least one of the crossovers to meet up with the other, if they don't just work straight off. It would be tempting to leave the heil crossover alone and adjust the mission woofers but this is something you may need to work out on your own. Do you have the mission crossover schematic or a photo?
No Allen, I do not have have the Mission schematic. However, the ESS crossover does have an adjustment pot for the Heils. I believe it is + - 3db. Could I use the ESS crossover in place of the Missions altogether?
This is not a simple process. There are many factors that go into driver selection for a speaker.
It is more than simply level matching the Heil to the Missions, so the ±3 dB pot is not going to cut it.
Some of the factors that you must consider in the process are:
Level
Crossover point
Phase
Matching horizontal dispersion angles between drivers
Proximity to other drivers
Impedances
The suggestion of using a dedicated amp with an electronic crossover (optimally a digital one) would give you the best chance of success.
You will also need to do comprehensive testing to validate your work. So, a microphone, audio adapter, PC, and associated software will be needed (along with knowledge on how to test loudspeakers). You can't do this with your ears.
A simpler route would be to see if you can get the Missions fixed.
It is more than simply level matching the Heil to the Missions, so the ±3 dB pot is not going to cut it.
Some of the factors that you must consider in the process are:
Level
Crossover point
Phase
Matching horizontal dispersion angles between drivers
Proximity to other drivers
Impedances
The suggestion of using a dedicated amp with an electronic crossover (optimally a digital one) would give you the best chance of success.
You will also need to do comprehensive testing to validate your work. So, a microphone, audio adapter, PC, and associated software will be needed (along with knowledge on how to test loudspeakers). You can't do this with your ears.
A simpler route would be to see if you can get the Missions fixed.
I doubt that 3dB will be enough.
Building crossovers can be a very involved process. If you are prepared to accept less than perfection and take it one step at a time then you have many options open. You could probably just use the heil crossover but you said you liked the midbass of the missions and it would seem a shame to just ditch the mission crossover without at least 'learning its secrets'.
The Missions are two way. I think the AMT monitors are also two way ? Not sure. But what would happen if I used the ESS crossover to drive the Mission drivers? would I necessarily loose the good characteristics of the Mission crossover? I do not have the schematic for the Missions. But I am not super critical. I have a mish mash of amps and speakers . Polk lsi9 and Sonas Faber Concertos for the sourrounds Polks driven by a Mac 2200 and a Mac 2300 for the Concertos.
Hi Rick! and Welcome to diyAudio!!!! 😀😀😀:
Check out this link for a crossover schematic to think over.
http://www.diyaudio.com/forums/planars-exotics/74391-ess-amt-1-am-crossover.html
The xovers ESS used were designed for a lot of adjustment to account for room placement and thus the user could "tweak" 'em to fit their needs. One problem is the age of the components comes into question - and the fact that the components used are not of the quality available today. I would suggest that you seriously consider replacing the electrolytic cap's and take a careful check of the pots, resistors, connectors, etc. for aging.
With my Great Heil's I went the simple rout - crossed over high - 6KHz - using a 6.8uf cap and to even out the SPL's I tossed in a 10Watt 4 ohm resistor.
2-Way Crossover Designer / Calculator
I hope that this is of some help to you!!
Check out this link for a crossover schematic to think over.
http://www.diyaudio.com/forums/planars-exotics/74391-ess-amt-1-am-crossover.html
The xovers ESS used were designed for a lot of adjustment to account for room placement and thus the user could "tweak" 'em to fit their needs. One problem is the age of the components comes into question - and the fact that the components used are not of the quality available today. I would suggest that you seriously consider replacing the electrolytic cap's and take a careful check of the pots, resistors, connectors, etc. for aging.
With my Great Heil's I went the simple rout - crossed over high - 6KHz - using a 6.8uf cap and to even out the SPL's I tossed in a 10Watt 4 ohm resistor.
2-Way Crossover Designer / Calculator
I hope that this is of some help to you!!
Attachments
Wow, that is an interesting setup you have there. How does it sound?
I am a little too hasty, because I didn't realize what the heck I was buying when I bought the BBE DS26. I thought it was an adjustable crossover that hooked directly to the drivers. My preamp doesnt even have balanced inputs! I hope I don't get stuck with it😕😕🙁
You have given yourself a clean slate. Going active does not relieve you from needing the same level of information and the same knowledge of where to take it. Unless you are set up to measure, you'll at least achieve a known target if you keep at least one of the passive crossovers.
Welllllllllllllllllllll - if you are a fan of Omnidirectional speakers I enjoy their sound very much. The AMT1's are clean and crisp without any "shout" that can be a problem with many other types of drivers. If you are new to "ribbon" - ESL - planer magnetic - transducers it will be heaven or hell depending upon your taste. YMMV The AMT's are a very open and free of distortion and allow endless hours of fatigue free listening. One of my final test for an acceptable speaker is how engaged with the music am I after an hour or two of listening. If I start out a listening session with music that I know and enjoy and am still sitting around having a blast after a couple of hours - well I think that I've a pretty good speaker on my hands. Heck - isn't listening to music and enjoying the experience what this hobby is all about???
The trick with the AMT's is finding some mids and woofers that will mate up with them. You need to use a responsive driver for this task and the best advice I can give you there is to look for one where the response curve is able to go a couple of octaves above your desired xover point.
Despite the claims about being able to go down to 800Hz I wouldn't suggest you try using the Heil's below 2kHz - take a look at this link and print out the PDF. http://www.hifisound.de/oxid/oxid.p...937/ESS-1-AIR-MOTION-TRANSFORMER.-SELEKTIERT/
I suggest that you keep your current xover to drive your mid-woofers and come off of your input terminals with a 20uf cap and 4 ohm 10 watt resistor (5 watts might be good) in series to the + terminal of the AMT.
http://www.diyaudioandvideo.com/Calculator/XOver/
I'm using 4 ohms for the AMT and guessing at 8 ohms for your woofers and aiming for 2kHz xover...........
Regards - and happy tweaking!!!! 😀😀😀
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An externally hosted image should be here but it was not working when we last tested it.
I also bought the original crossovers in the photos. Could I use them off the input teminal from my Misssons? Instead of using a cap and a resistor?
Hi. I sent you a PM. The woofers on the Missions are 4 ohms. Two 8" 8 ohm in parallel.
You can download the Owners Manual at Mission 765 | Owners Manual, Service Manual, Schematics, Free Download | HiFi Engine
It doesn't have a schematic for the x'over - buuuuuut it does say that they cross 'em 2300Hz - and that they can be bi-amplified - which means that you can by-pass the part of the x-over used for HF.
I did respond to the PM - check you mail.....
It doesn't have a schematic for the x'over - buuuuuut it does say that they cross 'em 2300Hz - and that they can be bi-amplified - which means that you can by-pass the part of the x-over used for HF.
I did respond to the PM - check you mail.....
c2cthomas, the crossovers (traced from photos) are here if interested..http://www.diyaudio.com/forums/multi-way/190711-need-help-modifying-my-mission-speakers-ess-components.html#post2603832
Hi Allen - Thanks much for that bit of work! Rick has ordered some pieces from Parts Express and we had a chat on the phone today - soooooooo let's see how it goes...
I dare conject that the Mission xover is much higher than need be with the Heils.
By crossing over lower you could enjoy the better quality of the Heil driver.
get a mini dsp and start experimenting. \ esp. good for you as you already have two amps.
By crossing over lower you could enjoy the better quality of the Heil driver.
get a mini dsp and start experimenting. \ esp. good for you as you already have two amps.
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