you might want to get with a SEAS millenium tweeter because the millenium is playing in the same ballpark about FS, but it is having more than twice the excursion. You may not be worried, but when you cross a tweeter at 1khz, that's something far more important, because it will struggle quickier, than the Xmax of your superwoofer for example 
Even with the low Fs of this tweeter, i would be a little affraid to cross this scanspeak that low. The excursion of a drivers grows exponentially, and there is a HUGE difference between crossing a 3/4 dome at 1500hz and crossing it at 1000hz.
also the millenium has proven it's ability to be crossed over very low, in linkwitz design for example.
Given the shape and size of a 12" cone, you may have some gain on your tweeter between 500hz and 4000hz. That means :
1 ° that you wan't to equalise that out for sure
2° that you may have some more facility to cross it over.
then, i would not feel comfortable in such a design without a superwoofer like the lab you were talking about. I imagine the diffraction effects of the cone of the woofer moving on the response of the tweeter must be a pretty hard thing to analyse, but i personnally would keep this cone movements to a minimum, meaning using a dedicated driver for bass duties.
then the result may be interresting !
Even with the low Fs of this tweeter, i would be a little affraid to cross this scanspeak that low. The excursion of a drivers grows exponentially, and there is a HUGE difference between crossing a 3/4 dome at 1500hz and crossing it at 1000hz.
also the millenium has proven it's ability to be crossed over very low, in linkwitz design for example.
Given the shape and size of a 12" cone, you may have some gain on your tweeter between 500hz and 4000hz. That means :
1 ° that you wan't to equalise that out for sure
2° that you may have some more facility to cross it over.
then, i would not feel comfortable in such a design without a superwoofer like the lab you were talking about. I imagine the diffraction effects of the cone of the woofer moving on the response of the tweeter must be a pretty hard thing to analyse, but i personnally would keep this cone movements to a minimum, meaning using a dedicated driver for bass duties.
then the result may be interresting !
I am going to have a dedicated bass driver - the Dayton. The open baffle will work down to about 100Hz where it will drop with a shelf -6dB and the Dayton will start to fill in. (don’t ask why, I’ll tell you if it works out!)
Your right the SEAS tweeter looks nice too, but there are pro’s and cons for both tweeters!
Seas Pros:
Over double the excursion
Known tweeter with a good rep
Scan-Speak Pros:
Frequency response is flatter below 1.5KHz (seas rolls-off slightly)
Higher sensitivity
Higher power handling (though rated as IEC, is this RMS or what?)
Smaller and thinner, makes it easier to place in the woofers centre
New tweeter; might be REALLY good.
My main concern is the SEAS roll-off that starts below 1.5KHz. It may have more excursion, but if I were to EQ it flat to 1KHz, like the Scan-Speak is, then maybe it would have as little excursion left over as the scan-speak does. What ya think?
Thanks Nemophyle, now I don't know which to choose!
So, now, opinions please! Which would be your choice for this application??
Your right the SEAS tweeter looks nice too, but there are pro’s and cons for both tweeters!
Seas Pros:
Over double the excursion
Known tweeter with a good rep
Scan-Speak Pros:
Frequency response is flatter below 1.5KHz (seas rolls-off slightly)
Higher sensitivity
Higher power handling (though rated as IEC, is this RMS or what?)
Smaller and thinner, makes it easier to place in the woofers centre
New tweeter; might be REALLY good.
My main concern is the SEAS roll-off that starts below 1.5KHz. It may have more excursion, but if I were to EQ it flat to 1KHz, like the Scan-Speak is, then maybe it would have as little excursion left over as the scan-speak does. What ya think?
Thanks Nemophyle, now I don't know which to choose!
So, now, opinions please! Which would be your choice for this application??
Some info on the RAAL 140-15D.
Here are measurements of it with no baffle, mounted on top of a thin pole. (to emulate no baffle)
On axis
20degreese off-axis
There are also plans to produce a version of both the 140 and 70 ribbons with a slightly thicker ribbon and multiple impedance taps to give more low frequency extension and versatility.
Here are measurements of it with no baffle, mounted on top of a thin pole. (to emulate no baffle)
On axis
An externally hosted image should be here but it was not working when we last tested it.
20degreese off-axis
An externally hosted image should be here but it was not working when we last tested it.
There are also plans to produce a version of both the 140 and 70 ribbons with a slightly thicker ribbon and multiple impedance taps to give more low frequency extension and versatility.
Some info from Eminence... 'The Definimax 12 and Magnum 12 are exactly the same speaker. We have made changes to the 15 and 18 to create the new and improved Definimax series, but the 12 was a newer design and we decided it was fine as is.'
Hence the differences you see in the published frequency response charts are merely the fact it was another different measurement.
Hence the differences you see in the published frequency response charts are merely the fact it was another different measurement.
Tenson said:I am going to have a dedicated bass driver - the Dayton. The open baffle will work down to about 100Hz where it will drop with a shelf -6dB and the Dayton will start to fill in. (don’t ask why, I’ll tell you if it works out!)
Your right the SEAS tweeter looks nice too, but there are pro’s and cons for both tweeters!
Seas Pros:
Over double the excursion
Known tweeter with a good rep
Scan-Speak Pros:
Frequency response is flatter below 1.5KHz (seas rolls-off slightly)
Higher sensitivity
Higher power handling (though rated as IEC, is this RMS or what?)
Smaller and thinner, makes it easier to place in the woofers centre
New tweeter; might be REALLY good.
My main concern is the SEAS roll-off that starts below 1.5KHz. It may have more excursion, but if I were to EQ it flat to 1KHz, like the Scan-Speak is, then maybe it would have as little excursion left over as the scan-speak does. What ya think?
Thanks Nemophyle, now I don't know which to choose!
So, now, opinions please! Which would be your choice for this application??
This is basically due to the differences in baffle masurements. The SS is measured in an infinite baffle. The Seas in an IEC baffle.
I talked to Mr Idland at the Seas R&D lab about their Crescendo and its performance at lower frequencies. He told me that all tests he had done (and I know it is a lot of tests) show that in a normal baffle this tweeter tends to get some amplification resulting in a very flat response down to 1-1,5 kHz.
I am afraid something will happen with the SS as well in this area (as this happens to all other drivers) when the surrounding environment is more realistic, so comparing these two by their white papers is really wrong in my opinion.
Measuring in an infinite baffle is really interesting! ...if you build infinite baffle speakers
Ooo00oh I'm excited, my Eminence Magnum 12HO should arrive tomorrow!
Then I just need to decide if they play nicely up to 1-1.5KHz for x-over to the Seas tweeter or if I want to change the driver, or use a Manger MSW instead for frequencies above 300Hz. So many variables! I hate waiting for burn in as well
Then I just need to decide if they play nicely up to 1-1.5KHz for x-over to the Seas tweeter or if I want to change the driver, or use a Manger MSW instead for frequencies above 300Hz. So many variables! I hate waiting for burn in as well
Well I thought if I can't get the Eminence to run nicely for a 1KHz or so xover then I will either try the Supravox 285 GMF which should do that no problem, OR I could use a 'Manger Sound Transducer' for everything above about 300Hz and use the Eminence below that.
I had a quick listen to the Magnum 12HO and it does seem very clean sounding. It also has an amazingly stiff suspension and the dust-cap is really, really tough!
I need to actually get a tweeter and try to Xover to it I think and see how it works.
I had a quick listen to the Magnum 12HO and it does seem very clean sounding. It also has an amazingly stiff suspension and the dust-cap is really, really tough!
I need to actually get a tweeter and try to Xover to it I think and see how it works.
I don't see this specifically mentioned, but apologies if it it has. What people are concerned about is that the wonderful flat curve of the tweeter is graphed at 1 watt input. at higher outputs (possibly 1.5 watts!) the x-max will be exceeded and the curve will look nothing like it does at one watt. At some output power, it won't have a nice flat curve at those lower frequencies- it will roll off and be very distorted.
So saying that the Scan Speak is flatter lower is just a guess- its ASSSUMING that x-max isn't exceeded
Since you don't have information on excursion at various output levels, this is hard to predict.
By wanting not considering another woofer you have also limited yourself. Other 12 " woofers will produce higher frequencies. As you have pointed out, it has a very heavy , stiff cone, which helps explain why its graph shows pretty low rolloff.
My understanding of this type of Scan Speak is that they do reproduce lower frequencies more eagerly than most tweeters BUT can run out of x-max. I suspect the Seas won't be much better, but it appears that the greater x-max might help , but no way of knowing for sure. As you said, it rolls off at lower frenquencies.
If you also weren't mentioning that you want quite high volume, we wouldn't be as concerned.
Oh well, you can experiment! Also it might make a great 3-way if it doesn't work as a 2 way!!
So saying that the Scan Speak is flatter lower is just a guess- its ASSSUMING that x-max isn't exceeded
Since you don't have information on excursion at various output levels, this is hard to predict.
By wanting not considering another woofer you have also limited yourself. Other 12 " woofers will produce higher frequencies. As you have pointed out, it has a very heavy , stiff cone, which helps explain why its graph shows pretty low rolloff.
My understanding of this type of Scan Speak is that they do reproduce lower frequencies more eagerly than most tweeters BUT can run out of x-max. I suspect the Seas won't be much better, but it appears that the greater x-max might help , but no way of knowing for sure. As you said, it rolls off at lower frenquencies.
If you also weren't mentioning that you want quite high volume, we wouldn't be as concerned.
Oh well, you can experiment! Also it might make a great 3-way if it doesn't work as a 2 way!!
Well I am undecided about the Magnum 12HO for high frequencies.
I hooked it up with the tweeter from my PMC's which also crosses at 1.4KHz. I have not got any of this in a baffle btw, just propped up on a chair, but it sounds to me like while the Magnum12HO is indeed very clean up to the high frequencies, it is not that transparent or detailed. Vocals are not bad at all, but the background information gets lost a little bit. Still, this might just be due to not having them on a baffle or even setting up the xover properly with measurements and so on.
I think my plan of action for tomorrow is to knock together a baffle for them, then actually take some measurements to set the Xover.
At that point if I am still not completely happy with its performance I think I will either give the Supravox 285GMF a go, or use the Manger MSW.
I will go hear the Manger as soon as I can to see if it is even suitable for me.
The Supravox is supposed to be very good indeed for high frequencies, but it doesn't produce such high SPL. It is not far off though! If I use it to 47Hz rather than 40Hz like the Magnum, then it has about the same Max SPL.
How big is the voice-coil in the Supravox 285GMF? Is it 1”?
Any suggestions for high quality tweeters that could fit in the dust-cap of the Supravox and Xover at around 2-2.5KHz? I can still use a sharp Xover.
I hooked it up with the tweeter from my PMC's which also crosses at 1.4KHz. I have not got any of this in a baffle btw, just propped up on a chair, but it sounds to me like while the Magnum12HO is indeed very clean up to the high frequencies, it is not that transparent or detailed. Vocals are not bad at all, but the background information gets lost a little bit. Still, this might just be due to not having them on a baffle or even setting up the xover properly with measurements and so on.
I think my plan of action for tomorrow is to knock together a baffle for them, then actually take some measurements to set the Xover.
At that point if I am still not completely happy with its performance I think I will either give the Supravox 285GMF a go, or use the Manger MSW.
I will go hear the Manger as soon as I can to see if it is even suitable for me.
The Supravox is supposed to be very good indeed for high frequencies, but it doesn't produce such high SPL. It is not far off though! If I use it to 47Hz rather than 40Hz like the Magnum, then it has about the same Max SPL.
How big is the voice-coil in the Supravox 285GMF? Is it 1”?
Any suggestions for high quality tweeters that could fit in the dust-cap of the Supravox and Xover at around 2-2.5KHz? I can still use a sharp Xover.
Tenson said:
I'm aware of only one tweeter manufacturer that makes a small tweeter with a large x-max. (and of course it will need quite a bit of modification to reduce its size, and will need a fair bit more power relative to something like either the Magnum or the supravox.)
http://www.hiquphon.dk/page1.html
Zaph has tested some of them here:
http://www.zaphaudio.com/tweetermishmash/
Frankly though, if you are "sold" on the idea of a concentric loudspeaker (in the mids an treble) then you would likely be better off with a purpose built speaker that acomplishes this..
Seas has some with a traditional dome tweeter. Cabasse has some "odd-ball" offerings.
Other sources have compression driver tweeters. In particular:
Beyma 8BX
http://profesional.beyma.com/ENGLISH/producto.php
Radian Audio 508/2BC
http://www.partsexpress.com/pe/pshowdetl.cfm?&DID=7&Partnumber=294-718&ctab=2#Tabs
BMS 5CN144 & 8CN252
http://www.bmspro.info/index.php?show=item&usbid=10283&id=5059989
There are numerous drivers that are based on 12" and 15" midbasses (with a coaxial mount). But unless the compression driver is crossed quite low these usually have audible coloration.
Probably the most "potent" of the coaxial mid-tweet is the McCauley 10" closed back midrange.
http://www.mccauleysound.com/component_overview.cfm?ID=114
I've often wondered if this could be used with a BMS compression driver. (..or perhaps a Radian.) Its likely though that the McCauley dustcap would need modification to achieve a more transparent sound.
Of course if you don't mind the the lack of compressive force that you feel with direct radiating mids then there are always coaxial BMS compression drivers with a suitable horn (..and for that I'd look for Jean-Michel Le Cleac'h's horn calculator).
Documentation of my build begins here!
The Eminence Magnum 12HO's arrived and I ran in them in for 3 days.
I then got some white faced hardboard from the local wood yard and a bit of 2x1" and made some test baffles.
When I started off, I tried popping them on a chair with the tweeter from my PMC's and using the digital crossover. They sounded pretty good but pretty coloured too.
I then added them to these baffles and they got a little bit better.
I then got out my measurement equipment (ETF) and adjusted the crossover and EQ for the open baffle as well as time aligned them.
Ahhh.... much better!
But still not good enough! They had a slightly 'ommmm' sound to the lower range which masked detail.
I decided to take them upstairs to my normal listening room which is fully acoustically treated. MUCH BETTER! Imaging and soundstage are amazing. I had forgotten what a difference listening in an untreated room makes! Anyway they still didn’t have quite the transparency in the lower mid band that my active PMC's did.
I added some absorption behind the speakers (in additon to the low frequency bass traps I already had) and it cleared right up.
This is where I am now. I am shocked how good it sounds! SO dynamic, and detailed and the imaging is shocking.
I give a BIG thumbs up to the Eminence Magnum 12HO for midrange and bass duties. I am crossing at 1.2KHz 48dB/Octive. Off axis response changes slightly at the Xover point but not a lot at all (could have been the room!)
My next step is to do the crossover measurement again but this time outside to avoid room issues. Then I need to set my room corrective EQ for the way these new speakers interact with the room.
I am going to hear the Manger Audio MSW transducers in a Zerobox speaker tomorrow. I wonder if it can beat what I have now for mid and high frequencies....
Some pictures...
The Eminence Magnum 12HO's arrived and I ran in them in for 3 days.
I then got some white faced hardboard from the local wood yard and a bit of 2x1" and made some test baffles.
When I started off, I tried popping them on a chair with the tweeter from my PMC's and using the digital crossover. They sounded pretty good but pretty coloured too.
I then added them to these baffles and they got a little bit better.
I then got out my measurement equipment (ETF) and adjusted the crossover and EQ for the open baffle as well as time aligned them.
Ahhh.... much better!
But still not good enough! They had a slightly 'ommmm' sound to the lower range which masked detail.
I decided to take them upstairs to my normal listening room which is fully acoustically treated. MUCH BETTER! Imaging and soundstage are amazing. I had forgotten what a difference listening in an untreated room makes! Anyway they still didn’t have quite the transparency in the lower mid band that my active PMC's did.
I added some absorption behind the speakers (in additon to the low frequency bass traps I already had) and it cleared right up.
This is where I am now. I am shocked how good it sounds! SO dynamic, and detailed and the imaging is shocking.
I give a BIG thumbs up to the Eminence Magnum 12HO for midrange and bass duties. I am crossing at 1.2KHz 48dB/Octive. Off axis response changes slightly at the Xover point but not a lot at all (could have been the room!)
My next step is to do the crossover measurement again but this time outside to avoid room issues. Then I need to set my room corrective EQ for the way these new speakers interact with the room.
I am going to hear the Manger Audio MSW transducers in a Zerobox speaker tomorrow. I wonder if it can beat what I have now for mid and high frequencies....
Some pictures...
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
Simon, welcome to the wonderful world of open baffles! I think you mean chipboard (Melomine) rather than hardboard though.
How low can you go with those Eminence drivers on a relatively small baffle?
You have encouraged me to do something about my room, rather than just develop the speakers.
How low can you go with those Eminence drivers on a relatively small baffle?
You have encouraged me to do something about my room, rather than just develop the speakers.
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.