Thought I'd post my email/comment on MLTL vs OB
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From: Peter
Sent: 12 December 2008 11:39 AM
To: Joseph
Subject: Looking at MJK's site and saw your new work....
Dear Joseph,
I was looking at MJK's site and saw your new OBs. I also saw your MLTLs in the background. I was wondering about your impressions of the difference between the two types of speaker and whether there are any things that you would do differently that I could apply for my own project?
I have a 4x Alpha 15s + 2x Lowther EX3 + 2x FT17H to go into a new project with an active crossover. I also have a current license for MJKs worksheets which I am using for simulation and my wife who is not terribly enthusiastic about having another pair of speakers.
I look forward to hearing from you if you have time to respond.
Cheers
Peter
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Hi Peter,
You've got some impressive drivers and should be able to put something together that will compare with the best there is. With regards to the wife, a large open baffle 4 driver speaker will certainly upset her, mine softened a bit when I finished them with very nice glossy veneer, but no doubt they are a presence in our living room. There is no way a guest can sit in our lounge and pretend they are not there!
Comparing a full range (MLTL) with open baffle is a bit unfair as these are very different speakers, even though both are fairly unconventional designs. I lived with the MLTL for more than 2 years before I finished the OBs and thoroughly enjoy them, they certainly are not perfect hence my decision to build the OB's. I've got the Fostex FE 206 full range drivers which is incredible speakers when you don't play them too loud and in the right range. I do believe these are amongst the best there is for certain types of music e.g. unplugged acoustic vocals with not too much bass or too many instruments or classical piano. Unfortunately this started changing my music taste, obviously you will only listen to music that sounds good! A lot of rock music just sounded awful on the MLTL.
The OB's is a total different animal. Most designs I've seen match an open baffle mid range with either an H-frame or sealed bass woofer, I have chosen open baffle for the bass driver as well. I would imagine using H-frame or sealed would give you better low end and more slam? For me having the bass in the open baffle is what it is all about, this is certainly the driver that will benefit most from removing the box. If I have to describe the speakers the "quiet" first comes to mind. The bass is there when needed and gone just as quickly when not, no colorations or distortions. Directly comparing the OB's with the MLTL: they can play any music without any bias / distortion at very loud levels. Because of the way the OB interact with the room the music tends to come from the room as apposed to the MLTL's which have a fairly small sweet spot.
I do think my OB mids are not as good as the FE 206's even though the Seas Excel drivers are highly regarded. A good full ranger like the Lowther's assisted in the bass and upper ranges will certainly make a very good speaker. When doing this you will have 2 choices, let the full rangers play unfiltered and augment lower and upper ranges or alternatively limit the full rangers to the mid band only. The first option is only possible if you have an incredibly well behaved full ranger, any distortion or cone break up will immediately be heard in the OB's. The alternative to limit the midrange is a much safer option and will certainly allow higher listening levels with less distortion, the trade-off will be a more complex crossover and you will need to be careful to keep coherency between crossover ranges.
You will find the open baffle design very easy to implement, you won't need to do any modelling if you've got a flexible active crossover like the behringer dbx.
Start by choosing the mid-range band and crossover points and as a first attempt use a simple 2'nd order crossover. I'd suggest between 200-250 Hz for the low crossover. Then use a 2n'd order high filter on the 2 x Alphas starting at 100 Hz, move this lower until the bass and mid levels matches perfectly at the crossover points. One thing that surprised me is how easy it is for 2 x 15" drivers in an open baffle configuration to be matched with any mid range driver by moving the starting point of the bass crossover, this would of course be at the expense of the bottom end f0.
Personally I am very happy with the OB and would never change to a different design ever again. The OB's does have it's own strengths and weaknesses, most of them fixable in an active crossover.
I'd love to hear your impressions when you've got the Lowthers playing.
Regards,
Joseph
----------------------------------------------------------------------------
From: Peter
Sent: 12 December 2008 11:39 AM
To: Joseph
Subject: Looking at MJK's site and saw your new work....
Dear Joseph,
I was looking at MJK's site and saw your new OBs. I also saw your MLTLs in the background. I was wondering about your impressions of the difference between the two types of speaker and whether there are any things that you would do differently that I could apply for my own project?
I have a 4x Alpha 15s + 2x Lowther EX3 + 2x FT17H to go into a new project with an active crossover. I also have a current license for MJKs worksheets which I am using for simulation and my wife who is not terribly enthusiastic about having another pair of speakers.
I look forward to hearing from you if you have time to respond.
Cheers
Peter
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Hi Peter,
You've got some impressive drivers and should be able to put something together that will compare with the best there is. With regards to the wife, a large open baffle 4 driver speaker will certainly upset her, mine softened a bit when I finished them with very nice glossy veneer, but no doubt they are a presence in our living room. There is no way a guest can sit in our lounge and pretend they are not there!
Comparing a full range (MLTL) with open baffle is a bit unfair as these are very different speakers, even though both are fairly unconventional designs. I lived with the MLTL for more than 2 years before I finished the OBs and thoroughly enjoy them, they certainly are not perfect hence my decision to build the OB's. I've got the Fostex FE 206 full range drivers which is incredible speakers when you don't play them too loud and in the right range. I do believe these are amongst the best there is for certain types of music e.g. unplugged acoustic vocals with not too much bass or too many instruments or classical piano. Unfortunately this started changing my music taste, obviously you will only listen to music that sounds good! A lot of rock music just sounded awful on the MLTL.
The OB's is a total different animal. Most designs I've seen match an open baffle mid range with either an H-frame or sealed bass woofer, I have chosen open baffle for the bass driver as well. I would imagine using H-frame or sealed would give you better low end and more slam? For me having the bass in the open baffle is what it is all about, this is certainly the driver that will benefit most from removing the box. If I have to describe the speakers the "quiet" first comes to mind. The bass is there when needed and gone just as quickly when not, no colorations or distortions. Directly comparing the OB's with the MLTL: they can play any music without any bias / distortion at very loud levels. Because of the way the OB interact with the room the music tends to come from the room as apposed to the MLTL's which have a fairly small sweet spot.
I do think my OB mids are not as good as the FE 206's even though the Seas Excel drivers are highly regarded. A good full ranger like the Lowther's assisted in the bass and upper ranges will certainly make a very good speaker. When doing this you will have 2 choices, let the full rangers play unfiltered and augment lower and upper ranges or alternatively limit the full rangers to the mid band only. The first option is only possible if you have an incredibly well behaved full ranger, any distortion or cone break up will immediately be heard in the OB's. The alternative to limit the midrange is a much safer option and will certainly allow higher listening levels with less distortion, the trade-off will be a more complex crossover and you will need to be careful to keep coherency between crossover ranges.
You will find the open baffle design very easy to implement, you won't need to do any modelling if you've got a flexible active crossover like the behringer dbx.
Start by choosing the mid-range band and crossover points and as a first attempt use a simple 2'nd order crossover. I'd suggest between 200-250 Hz for the low crossover. Then use a 2n'd order high filter on the 2 x Alphas starting at 100 Hz, move this lower until the bass and mid levels matches perfectly at the crossover points. One thing that surprised me is how easy it is for 2 x 15" drivers in an open baffle configuration to be matched with any mid range driver by moving the starting point of the bass crossover, this would of course be at the expense of the bottom end f0.
Personally I am very happy with the OB and would never change to a different design ever again. The OB's does have it's own strengths and weaknesses, most of them fixable in an active crossover.
I'd love to hear your impressions when you've got the Lowthers playing.
Regards,
Joseph
Nice project.
Zaph Audio ZA14W08 could be good mid for 909-clone.
http://www.zaphaudio.com/ZA14W08/ZA14W08-datasheet.pdf
Zaph Audio ZA14W08 could be good mid for 909-clone.
http://www.zaphaudio.com/ZA14W08/ZA14W08-datasheet.pdf
I am thinking of having a go at this.
However I am considering using this mid THE ART OF SOUND PERFECTION BY SEAS - E0043-06S M15CH002
or possibly a scanspeak revelator 5".
Most likely stick with scanspeak revelator tweeter or use my existing Usher tweeter.
Kappalite 3015LF for bass.
The other option is replace mid and tweeter with Fostex FF85KeN
Feel free to comment
However I am considering using this mid THE ART OF SOUND PERFECTION BY SEAS - E0043-06S M15CH002
or possibly a scanspeak revelator 5".
Most likely stick with scanspeak revelator tweeter or use my existing Usher tweeter.
Kappalite 3015LF for bass.
The other option is replace mid and tweeter with Fostex FF85KeN
Feel free to comment
The problem with the M15CH002 is a dip in the 1k-2kHz area, will become worse ... Same problem with the revelator. I think the W15 is one of the best option.
If you want an excel driver use instead the W18NX
An other option is a peerless driver, i have used : 830991
I strongly recommend not to go higher than 2kHz with these drivers.
Nothing to say on the tweeter...
FF85KeN see Martin J.King job but with one woofer. Please add a tweeter
If you want an excel driver use instead the W18NX
An other option is a peerless driver, i have used : 830991
I strongly recommend not to go higher than 2kHz with these drivers.
Nothing to say on the tweeter...
FF85KeN see Martin J.King job but with one woofer. Please add a tweeter
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