In my search to build a pair of floorstanding speakers (or help build) i was given the following design to consider by a firm in Melbourne.
In a line down the front of the cabinet would be be 3 tweeters and 2 - 8" woofers. Facing out the rear or the box is a 4th tweeter directly behind the front 3. All tweeters are Kevlar and woofers are glass fibre. Linked by capacitors.
Has anyone seen any similar designs or can anyone enlighten me to why you would have a tweeter facing out the back of the box?
I'm a novice and this is my first entry.
In a line down the front of the cabinet would be be 3 tweeters and 2 - 8" woofers. Facing out the rear or the box is a 4th tweeter directly behind the front 3. All tweeters are Kevlar and woofers are glass fibre. Linked by capacitors.
Has anyone seen any similar designs or can anyone enlighten me to why you would have a tweeter facing out the back of the box?
I'm a novice and this is my first entry.
Angstrom Loudspeakers is using the same concept in their Obligato model (a tweeter on the back of the box). The magazine article (Québec-Audio Vol.6 No3) is saying that this approach help the on-axis frequency response. I have no idea if it is true or not.
this isa 2 part question.
1 3 tweeters in a vertical array
2. the rear tweeter.
using 3 tweeters in a vertical array has/was/is been/being done by VMPS, Polk and a few others. mostly it was done to increase th power handling of the speaker. what was done often was a complex XO where onl 1 tweeter operated in the10k + range, 2 tweeters in the 5k + range and all 3 in the 3k + range (these numbers are not accurate just a concept)
Not having heard the VMPS under critical circumstances (a CES is not a critical location) I canot comment on their sound (the tweeters were focal T120 versions - a similar tweeter was used by Dave Wilson on the WATT). The Polks SDA SRS used 4 tweeters made by a OEM for them. I did not like the sound. it was nasty. what little i heard of teh VMPS was better (even though the focals had a rising response above 10-12k)
my guess is dont do it unless your tweeter cannot handle the power. todays tweeters can evne the one that dont use ferro fluid (SS 9900 for example can handle 100W+ XOed at 12db at 2.5k).
2. the rear tweeter
This got a bit popular in the late 70s - mid 80s. Snell had a well known model (Type C i think) that used this to great effect. it did a lot (the Type C I used had a switch to turn the tweeter off or down by 6db). If youuse this it might make sense to include such a control.
hope this helps.
1 3 tweeters in a vertical array
2. the rear tweeter.
using 3 tweeters in a vertical array has/was/is been/being done by VMPS, Polk and a few others. mostly it was done to increase th power handling of the speaker. what was done often was a complex XO where onl 1 tweeter operated in the10k + range, 2 tweeters in the 5k + range and all 3 in the 3k + range (these numbers are not accurate just a concept)
Not having heard the VMPS under critical circumstances (a CES is not a critical location) I canot comment on their sound (the tweeters were focal T120 versions - a similar tweeter was used by Dave Wilson on the WATT). The Polks SDA SRS used 4 tweeters made by a OEM for them. I did not like the sound. it was nasty. what little i heard of teh VMPS was better (even though the focals had a rising response above 10-12k)
my guess is dont do it unless your tweeter cannot handle the power. todays tweeters can evne the one that dont use ferro fluid (SS 9900 for example can handle 100W+ XOed at 12db at 2.5k).
2. the rear tweeter
This got a bit popular in the late 70s - mid 80s. Snell had a well known model (Type C i think) that used this to great effect. it did a lot (the Type C I used had a switch to turn the tweeter off or down by 6db). If youuse this it might make sense to include such a control.
hope this helps.
Occasionally you will come across speakers where tweeters, mids and even bass-mids are firing both front and rear.
Unlike a dipole, where the back speaker strokes inward while the front speaker strokes outward, (similar to the action of a completely unenclosed speaker), in a bipolar speaker both front and back speakers fire outward and inward at the same time.
The idea behind it is based on the fact that music does not sound good when a narrow beam is aimed at the listener, with the amplitude of sound off that beam sharply reduced. You might think it would, but it does not. Music sounds most natural when a series of reflections of reduced amplitude is added to the direct beam. It gives a sense of spaciousness, of naturalness. To create this sense of spaciousness, the off-axis sound of speaker, called dispersion, is included with the specs.
High frequency sound especially is difficult to get good dispersion out of. Look at a tweeter respnse chart-the high ranges have very low output 60 degrees off axis.
The bipolar speaker comes at this the other way. By purposely creating a sound field designed to bounce off the walls and come at the listener indirectly, it creates the sense of a speaker with very good dispersion.
There are highly rated commercial systems that use this principle. Some people like it, some don't.
Unlike a dipole, where the back speaker strokes inward while the front speaker strokes outward, (similar to the action of a completely unenclosed speaker), in a bipolar speaker both front and back speakers fire outward and inward at the same time.
The idea behind it is based on the fact that music does not sound good when a narrow beam is aimed at the listener, with the amplitude of sound off that beam sharply reduced. You might think it would, but it does not. Music sounds most natural when a series of reflections of reduced amplitude is added to the direct beam. It gives a sense of spaciousness, of naturalness. To create this sense of spaciousness, the off-axis sound of speaker, called dispersion, is included with the specs.
High frequency sound especially is difficult to get good dispersion out of. Look at a tweeter respnse chart-the high ranges have very low output 60 degrees off axis.
The bipolar speaker comes at this the other way. By purposely creating a sound field designed to bounce off the walls and come at the listener indirectly, it creates the sense of a speaker with very good dispersion.
There are highly rated commercial systems that use this principle. Some people like it, some don't.
Thakyou for the feedback. I kind of like the idea of dispersion off the wall for imaging purposes by the rear tweeter.
I was wondering if one of the front 3 tweeters should be replaced by a midrange but the guy who gave me the design said that its pointless as the woofers are full range. Your thoughts? Perhaps i should mention this speaker design is a sealed unit. No ports,vents etc. And, only the bottom woofer is sealed off from the others in like a sealed transmission line like structure (got the picture) I should also point out this is the same guy who builds the drivers.
Here is some tech info on the drivers i'm looking at using. Again your views on all this will assist me greatly.
Tweeter- freq. resp. 5khz-20khz
efficiency 93.70
rms 150w
grade A magnet size 78mm
8"woofer option (A)-freq resp. 40hz-20khz
efficiency 90.12
rms 100, pmpo 200
re ohm 7.43
OR
option (B) freq resp. 43hz-10khz
efficiency 87.43
rms 100 pmpo 200
re ohm 7.552
I was wondering if one of the front 3 tweeters should be replaced by a midrange but the guy who gave me the design said that its pointless as the woofers are full range. Your thoughts? Perhaps i should mention this speaker design is a sealed unit. No ports,vents etc. And, only the bottom woofer is sealed off from the others in like a sealed transmission line like structure (got the picture) I should also point out this is the same guy who builds the drivers.
Here is some tech info on the drivers i'm looking at using. Again your views on all this will assist me greatly.
Tweeter- freq. resp. 5khz-20khz
efficiency 93.70
rms 150w
grade A magnet size 78mm
8"woofer option (A)-freq resp. 40hz-20khz
efficiency 90.12
rms 100, pmpo 200
re ohm 7.43
OR
option (B) freq resp. 43hz-10khz
efficiency 87.43
rms 100 pmpo 200
re ohm 7.552
just as a refresh, what does pmpo stand for again? Max wattage with like a 1 khz signal or something like that?
Also its going to be hard to find an 8" woofer that plays upwards of 5 Khz well. Im sure there are some, but they are probably expensive, and they would probably not have specs formated like the ones above.
Not hatin, just helpin.
Also its going to be hard to find an 8" woofer that plays upwards of 5 Khz well. Im sure there are some, but they are probably expensive, and they would probably not have specs formated like the ones above.
Not hatin, just helpin.
i'm a little bit curious about the configuration. who designed these speakers? where can i have a look (or listen)? they might sound fantastic, but the specs seem very unusual indeed.
do they have a website or can you post some pics?
do they have a website or can you post some pics?
😀
This is the web site of the company in Melbourne who build the drivers. www.totalrecoil.com.au
If you look on the homepage you will see the plan of the speakers mentioned above that i think i will build. Unfortunately it seems only the centre channel can be viewed at the moment. I spoke to a guy there this morning (briefly)by the name of Boyd who said he only recently designed these speakers. He sounded of German origin.
There are plans for bookshelf and sub as well as another floorstanding speaker.. The sub uses a Comet woofer (i think). Has anyoneone used this sub before? What are your views?
In relation to home he mentioned it was about speed?
This is the web site of the company in Melbourne who build the drivers. www.totalrecoil.com.au
If you look on the homepage you will see the plan of the speakers mentioned above that i think i will build. Unfortunately it seems only the centre channel can be viewed at the moment. I spoke to a guy there this morning (briefly)by the name of Boyd who said he only recently designed these speakers. He sounded of German origin.
There are plans for bookshelf and sub as well as another floorstanding speaker.. The sub uses a Comet woofer (i think). Has anyoneone used this sub before? What are your views?
In relation to home he mentioned it was about speed?
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