When i first saw the subject line last night, i new it was you that had posted it : )
Good idea about the "wings". I've used similar approaches to extend baffles on smaller stand mounted monitors before, but these usually extended below the cabinets and not to the sides. This type of baffle extension is typically called a "baffle beard" and can be fine tuned via different lengths and angles. This approach can help extend the bottom end of smaller designs while also minimizing "holes" in the frequency response that were caused by cancellation from "floor bounce".
Since you could not really extend the baffle below your cabinet due to the design, your idea about going off the sides and making them adjustable is quite creative and simple to boot. Not only can you tailor the amount of reinforcement, but you're not really running into big-time problems with diffraction this way due to the angular nature of the design. Two birds with one stone ( so to speak ). My only concern with this is that the "wings" will tend to resonate unless you've found some way to rigidly couple them into position and keep them anchored. Have you looked into this or does it not seem to be a problem at this point in time ?
While i've got a couple of other speaker projects i have to get done first, your tinkering with a single driver like this has gotten me wanting to experiment a little more with something i had previously thought about. I have a couple of Pioneer full range 8" drivers with whizzer's that i'm going to experiment with. My brother had used them in a previous project but ended up getting TOO "creative" and ruined the project.
I'm thinking of doing something along the lines of a Shahinian design i.e. mounting the driver on the top of the cabinet with a gradually sloped baffle pointing somewhat forward. The rear wave of the driver would be loaded using a TATL ( Tapered Acoustic Transmission Line ). This would give me a near 360* radiation pattern with a slight forward axis. The TL would reinforce the bottom end without making it peaky or introducing big impedance swings. While the driver is relatively efficient ( 92 - 94 dB's if i recall correctly ), it is nothing like your Lowther. Then again, my smallest amp is 30+ wpc : )
As far as driver mods go for my project, i'd:
1) Damp the basket of the driver to miminize ringing. Depending on the mass of the individual driver and it's basket, how it is mounted, etc... this can DRASTICALLY reduce peakiness in the upper midrange area. If you haven't done that with your Lowther, you need to check into it. I think that this is responsible for what many people refer to as "shout" in this type of driver. I have seen basket damping alter the linearity and frequency response of a driver by SEVERAL dB's.
2) Treat the cone to help stiffen and damp break-up.
3) Support the whizzer by placing high density foam between the rear of the whizzer and the immediate area of the cone behind it. This should keep the whizzer from flexing independently of the cone. This should also minimize the reflections that take place from the signal bouncing off the whizzer and back into the cone behind it. Another potential solution for minimizing "shout" or harsness in the upper mids.
Other than that, it is good to see something "good" come out of a "mistake". Some people would have pissed and moaned about receiving the wrong drivers. You made a silk purse out of a sow's ear : ) Sean
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Good idea about the "wings". I've used similar approaches to extend baffles on smaller stand mounted monitors before, but these usually extended below the cabinets and not to the sides. This type of baffle extension is typically called a "baffle beard" and can be fine tuned via different lengths and angles. This approach can help extend the bottom end of smaller designs while also minimizing "holes" in the frequency response that were caused by cancellation from "floor bounce".
Since you could not really extend the baffle below your cabinet due to the design, your idea about going off the sides and making them adjustable is quite creative and simple to boot. Not only can you tailor the amount of reinforcement, but you're not really running into big-time problems with diffraction this way due to the angular nature of the design. Two birds with one stone ( so to speak ). My only concern with this is that the "wings" will tend to resonate unless you've found some way to rigidly couple them into position and keep them anchored. Have you looked into this or does it not seem to be a problem at this point in time ?
While i've got a couple of other speaker projects i have to get done first, your tinkering with a single driver like this has gotten me wanting to experiment a little more with something i had previously thought about. I have a couple of Pioneer full range 8" drivers with whizzer's that i'm going to experiment with. My brother had used them in a previous project but ended up getting TOO "creative" and ruined the project.
I'm thinking of doing something along the lines of a Shahinian design i.e. mounting the driver on the top of the cabinet with a gradually sloped baffle pointing somewhat forward. The rear wave of the driver would be loaded using a TATL ( Tapered Acoustic Transmission Line ). This would give me a near 360* radiation pattern with a slight forward axis. The TL would reinforce the bottom end without making it peaky or introducing big impedance swings. While the driver is relatively efficient ( 92 - 94 dB's if i recall correctly ), it is nothing like your Lowther. Then again, my smallest amp is 30+ wpc : )
As far as driver mods go for my project, i'd:
1) Damp the basket of the driver to miminize ringing. Depending on the mass of the individual driver and it's basket, how it is mounted, etc... this can DRASTICALLY reduce peakiness in the upper midrange area. If you haven't done that with your Lowther, you need to check into it. I think that this is responsible for what many people refer to as "shout" in this type of driver. I have seen basket damping alter the linearity and frequency response of a driver by SEVERAL dB's.
2) Treat the cone to help stiffen and damp break-up.
3) Support the whizzer by placing high density foam between the rear of the whizzer and the immediate area of the cone behind it. This should keep the whizzer from flexing independently of the cone. This should also minimize the reflections that take place from the signal bouncing off the whizzer and back into the cone behind it. Another potential solution for minimizing "shout" or harsness in the upper mids.
Other than that, it is good to see something "good" come out of a "mistake". Some people would have pissed and moaned about receiving the wrong drivers. You made a silk purse out of a sow's ear : ) Sean
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