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Looking to build a high efficiency, full range speaker is a bit of a task due to most high efficiency drivers are made for the PA crowd, and not always designed with sound quality in mind.
Fortunately, Acoustic Elegance has a nice selection of high efficiency drivers with ultra-low distortion and clean response. They're seen in a few high end designs, most notably Avalon's new $300K flagship, the Tesseract.
For this project, I will be using a 15" woofer designed for deep response in sealed enclosures, the AE TD-15S. The lower midrange will be another 15" woofer, the TD-15M. It has clean response and ultra low distortion past 1K, allowing a lot of flexibility for a crossover point and slope. Both drivers have efficiency @ 98db@1w. The lower midrange will be in a cardioid resistant type enclosure. The sides are vented and covered with either felt or fiberglass, allowing leakage out the sides of the enclosure which causes cancellation of sound greater than 60* off axis. This enclosure is still a work in progress as I've managed clean cardioid response through only half of it's bandwidth so far.
For the mid frequencies is a SEOS-24 waveguide with a TBD compression driver. I find SEOS waveguides don't load as low as other "horns" with the same outside dimensions, but this is a necessity as these style waveguides, used correctly, don't suffer from horn honk. For a compression driver I'm consider Faital Pro or BMS. BMS makes a fantastic midrange(and coax) compression driver that will fit my needs, Faital's CD's are no slouches either, but I need to do a little more research on them to confirm if they will or will not work for my application(exit angle discrepancy). This horn/CD combo will be used from a minimum of 500hz up to @ 5k, depending on my pending measurements and which slopes I choose.
The HF unit is still TBD, but I have a general idea of what I will be using. I find that most CD's don't have the air and top end detail of a high end dome or ribbon, but domes and ribbons have much different dispersion characteristics than your average horn or waveguide. I sourced a pair of SEOS waveguides made for an European ribbon, but they also happen to fit a pair of OEM RAAL ribbons I have on hand. The waveguides managed to give the ribbon a little boost in efficiency, lower distortion, and also match the directivity(dispersion) of the SEOS-24 waveguide. But I'm also eying one of Scanspeak's high end domes in a similar waveguide as I had the ribbons slanted towards another project.
I still need to acquire a few more parts and build more test enclosures before proceeding with the final build, so please don't expect this to be completed for at least a few more months.
Here is a quick preview of the mid enclosure and horn placed on top of my measurement lazy-Suzan and ripole sub test box.
The final enclosure will be built with 1.5" baltic birch ply, the finish is still TBD.
Mike
Fortunately, Acoustic Elegance has a nice selection of high efficiency drivers with ultra-low distortion and clean response. They're seen in a few high end designs, most notably Avalon's new $300K flagship, the Tesseract.
For this project, I will be using a 15" woofer designed for deep response in sealed enclosures, the AE TD-15S. The lower midrange will be another 15" woofer, the TD-15M. It has clean response and ultra low distortion past 1K, allowing a lot of flexibility for a crossover point and slope. Both drivers have efficiency @ 98db@1w. The lower midrange will be in a cardioid resistant type enclosure. The sides are vented and covered with either felt or fiberglass, allowing leakage out the sides of the enclosure which causes cancellation of sound greater than 60* off axis. This enclosure is still a work in progress as I've managed clean cardioid response through only half of it's bandwidth so far.
For the mid frequencies is a SEOS-24 waveguide with a TBD compression driver. I find SEOS waveguides don't load as low as other "horns" with the same outside dimensions, but this is a necessity as these style waveguides, used correctly, don't suffer from horn honk. For a compression driver I'm consider Faital Pro or BMS. BMS makes a fantastic midrange(and coax) compression driver that will fit my needs, Faital's CD's are no slouches either, but I need to do a little more research on them to confirm if they will or will not work for my application(exit angle discrepancy). This horn/CD combo will be used from a minimum of 500hz up to @ 5k, depending on my pending measurements and which slopes I choose.
The HF unit is still TBD, but I have a general idea of what I will be using. I find that most CD's don't have the air and top end detail of a high end dome or ribbon, but domes and ribbons have much different dispersion characteristics than your average horn or waveguide. I sourced a pair of SEOS waveguides made for an European ribbon, but they also happen to fit a pair of OEM RAAL ribbons I have on hand. The waveguides managed to give the ribbon a little boost in efficiency, lower distortion, and also match the directivity(dispersion) of the SEOS-24 waveguide. But I'm also eying one of Scanspeak's high end domes in a similar waveguide as I had the ribbons slanted towards another project.
I still need to acquire a few more parts and build more test enclosures before proceeding with the final build, so please don't expect this to be completed for at least a few more months.
Here is a quick preview of the mid enclosure and horn placed on top of my measurement lazy-Suzan and ripole sub test box.
The final enclosure will be built with 1.5" baltic birch ply, the finish is still TBD.
Mike
