FAATT stands for Fullrange And Ambient Tweeter Technology, new invention 😀
Since our livingroom has changed I need to ditch my two-way floorstanding loudspeakers and have to build something small.
In short the idea is as follows:
-TangBand W4-1320 SIF (fullrange)
-Dayton ND16FA (ambient tweeter, 10khz and up)
-6.5liters
-passive radiator
-ambient tweeter will be placed on the top/backside of the enclosure and will project to the rearwall of the living room under a 45degree angle.
On-axis the tweeter should not be audible to keep all the benefits of the fullrange driver, some 20 degrees off-axis the ambient tweeter should kick-in to compensate the loss of highs from the 4" Tangband.
I've done something similar before with the Tangband W5-1611sa, it worked excellent.
Since our livingroom has changed I need to ditch my two-way floorstanding loudspeakers and have to build something small.
In short the idea is as follows:
-TangBand W4-1320 SIF (fullrange)
-Dayton ND16FA (ambient tweeter, 10khz and up)
-6.5liters
-passive radiator
-ambient tweeter will be placed on the top/backside of the enclosure and will project to the rearwall of the living room under a 45degree angle.
On-axis the tweeter should not be audible to keep all the benefits of the fullrange driver, some 20 degrees off-axis the ambient tweeter should kick-in to compensate the loss of highs from the 4" Tangband.
I've done something similar before with the Tangband W5-1611sa, it worked excellent.
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You might consider a DCR box to keep it simple and still achieve good bass extension with more controlled cone movement. I know IG81 had good success with the W4 bamboo in a DCR. A sketch of what you propose would be useful. I am not sure how the up or rear firing done tweeter integrates with the front driver.
This is how I've done it with an older design of mine.
The 16mm dome is connected with a small capacitor only, the value is found by trial-n-error (it should be somewhere around 1uf)
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A DCR is a good choice to extend the low-end be it that the box size will increase (or did IG81 keep it around 6.5liters?). That's the reason I choose to use a passive radiator so I'll be able to tune it slightly lower without having to install a long tube that will introduce a port-resonance(standing wave inside the port).
Edit: found the thread of IG81 http://www.diyaudio.com/forums/full-range/236541-tb-w4-1320sif-double-bass-reflex.html thnx!
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Volume of DCR is same as BR, chambers get divided with 2:1 ratio. Three vents all same size are typically used. Use a model for best results on how to size chamber and vent. There is an online calculator somewhere.
As far as my knowledge about DCR goes the added advantage would be a reduced distortion at the 2nd tuning frequency (inner tube).
The passive radiator I want to use has the advantage that there's no port-resonance and that there's less mid-range "junk".
I think I'll stick with the PR 🙂
The passive radiator I want to use has the advantage that there's no port-resonance and that there's less mid-range "junk".
I think I'll stick with the PR 🙂
Just a quick sketchup drawing of the enclosure, nothing fancy. You can see the 45degree angled surface at the back of the enclosure where the "ambient" tweeter will be put.
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If you still have the VC mounted you can put a resistor across it to tune the damping (or use L-pad for variable damping). Did you model the cabinet response with the PR yet? Are you adding mass to the cone (looks like it as I see the flat black disc on the cone). Nice thing about leaving the VC is you measure the T/S params of the new PR you built.
The VC isn't there anymore.....
I'll tune it the way I did with all my homebrew PR's. The flat disk is glued on to the "normal" cone so there's a cavity which I can fill with polyurethane foam, after that I can insert a thread(bolt) that can accommodate metal rings(washer) to add weight. After installing the PR I run sinewave's and add/remove weight until the excursion of the PR is max and that of the active driver is the least at the desired frequency.
Got the drivers this weekend! Potent little driver it is 😀
I did a short test with the passive radiator and concluded I had to remove all the rings(weight) else the tuning would be to low. The tuning now lies somewhere between 45-50hz, lower then I intended (65hz). But, I really like the sound of the lower tuning. For a 6liter enclosure they go low, really, I was shocked at the low-end that came out of that small box. The W4-1320 can also handle some abuse, I'm more then satisfied with these drivers, kudos to TangBand.
I also find that the passive radiator has a unique sound, it has the extension of bassreflex but sound more like a closed box, probably because of the lack of midrange colouration and other "noises" that may come out of a port.
I did a short test with the passive radiator and concluded I had to remove all the rings(weight) else the tuning would be to low. The tuning now lies somewhere between 45-50hz, lower then I intended (65hz). But, I really like the sound of the lower tuning. For a 6liter enclosure they go low, really, I was shocked at the low-end that came out of that small box. The W4-1320 can also handle some abuse, I'm more then satisfied with these drivers, kudos to TangBand.
I also find that the passive radiator has a unique sound, it has the extension of bassreflex but sound more like a closed box, probably because of the lack of midrange colouration and other "noises" that may come out of a port.
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Very nice - can we see photos of the box with drivers installed? Measurements would be great - love to see how the bass from a 1320 and DIY PR looks.
Hopefully I can finish the enclosures upcoming weekend, then I'll install the drivers.
I'll do some measurements next week (hope the weather is good so I can do them outside)
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