Hi Guydio,
In the thread, there is a measured speaker impedance using a DATS. This is the impedance as a function of frequency that your amplifier will "see". It dips no lower than 7ohms and is on average probably closer to 11 or 12 ohms - very similar to the rating of the BBC's LS3/5A. I will be calling my speakers the "Rockville" - named for the town in Maryland where the Civil War era barn that provided the antique white oak used for the battens was repurposed from.
I would call this an "8ohm" speaker.
In the thread, there is a measured speaker impedance using a DATS. This is the impedance as a function of frequency that your amplifier will "see". It dips no lower than 7ohms and is on average probably closer to 11 or 12 ohms - very similar to the rating of the BBC's LS3/5A. I will be calling my speakers the "Rockville" - named for the town in Maryland where the Civil War era barn that provided the antique white oak used for the battens was repurposed from.
I would call this an "8ohm" speaker.
I just discovered this thread after a decade layoff from speaker building. I bought a pair of Aurasound Whispers to put in my car to replace the tweeters and then decided to go a different direction.
I wanted to see what the Whispers were like, but I didn't want to spend the time to build a proper box. I found this thread and decided to give it a try. While my wife was watching her favorite football team lose another game, I built these little guys. I used the box dimensions given on the PE website and it worked out well. I built a vented box and then wrapped the front and sides with a final piece. It makes it a little less ugly and the front and sides are double thickness. For a micro desktop computer speakers these are pretty good. A little forward in the midrange, but overall very listenable. I paired them with a sub and they are entirely satisfactory.
I made them out of a piece of Elmer's foamboard that a student discarded after the science fair and the Whispers were on sale for $12.50. Not bad. Sure, they're ugly, but it's hard to beat that instant gratification.
Now I'm pondering what is next. Maybe a Cornu spiral with these drivers? I also have a pair of 40-1197 and 40-1354 drivers. Or maybe I should forget those old drivers and build something with the Vifa TC9FD. That .4 Karlsonator sure looks interesting.
I wanted to see what the Whispers were like, but I didn't want to spend the time to build a proper box. I found this thread and decided to give it a try. While my wife was watching her favorite football team lose another game, I built these little guys. I used the box dimensions given on the PE website and it worked out well. I built a vented box and then wrapped the front and sides with a final piece. It makes it a little less ugly and the front and sides are double thickness. For a micro desktop computer speakers these are pretty good. A little forward in the midrange, but overall very listenable. I paired them with a sub and they are entirely satisfactory.
I made them out of a piece of Elmer's foamboard that a student discarded after the science fair and the Whispers were on sale for $12.50. Not bad. Sure, they're ugly, but it's hard to beat that instant gratification.
Now I'm pondering what is next. Maybe a Cornu spiral with these drivers? I also have a pair of 40-1197 and 40-1354 drivers. Or maybe I should forget those old drivers and build something with the Vifa TC9FD. That .4 Karlsonator sure looks interesting.
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Hi Db6546,
Those are good looking speakers for foam core! Good idea to wrap a second layer on the front and sides to achieve the round over effect. If they sound forward, it’s because of baffle step (loss of bass below circa 1kHz due to small baffle). Use a BSC circuit with a 1mH and 5ohm to 6.7ohm resistor in parallel to attenuate the highs with a shelf function so that bass and highs are level. That’s for 8ohm driver. For 4ohm driver use 0.5mH inductor.
The radio shack 1197 driver has a Karlsonator plan. Do a search and you will see it. It’s nice sounding.
Congrats on your new speakers. You are going to start an amazing foam core collection, I can tell.
There is
Those are good looking speakers for foam core! Good idea to wrap a second layer on the front and sides to achieve the round over effect. If they sound forward, it’s because of baffle step (loss of bass below circa 1kHz due to small baffle). Use a BSC circuit with a 1mH and 5ohm to 6.7ohm resistor in parallel to attenuate the highs with a shelf function so that bass and highs are level. That’s for 8ohm driver. For 4ohm driver use 0.5mH inductor.
The radio shack 1197 driver has a Karlsonator plan. Do a search and you will see it. It’s nice sounding.
Congrats on your new speakers. You are going to start an amazing foam core collection, I can tell.
There is
Thanks, xrk971,
I looked through my spare parts and don't have any 1.0 mh inductors. Will the cheap iron core be okay, or should I get the air core?
Then again, if I put these drivers in a Cornu, could I avoid the BSC circuit altogether?
I found the plans for the 40-1197 - 0.44x for H & D and 0.55x W. Any BSC circuit required for this driver?
I can see how this can get addictive.
Now I have to go order some foam and damping materials....
I looked through my spare parts and don't have any 1.0 mh inductors. Will the cheap iron core be okay, or should I get the air core?
Then again, if I put these drivers in a Cornu, could I avoid the BSC circuit altogether?
I found the plans for the 40-1197 - 0.44x for H & D and 0.55x W. Any BSC circuit required for this driver?
I can see how this can get addictive.
Now I have to go order some foam and damping materials....
Iron core inductor is fine. At the low currents you are running you aren’t going to run into any saturation issues.
You won’t need it for Cornu as that has too much bass and will require stuffing to tame the bass.
The Karlsonators won’t require BSC either as they also generate bass gain from the design.
You won’t need it for Cornu as that has too much bass and will require stuffing to tame the bass.
The Karlsonators won’t require BSC either as they also generate bass gain from the design.
Thanks. I did some more digging and found two pairs of ferrite (?) rod inductors. .58 mh and .52 mh. I think I'll hook them up in series and see how it sounds. I have plenty of resistors to experiment with.
Thanks for answering my noob questions. I'm working through the thread and trying to get back up to speed on many of the things that I've forgotten.
Thanks for answering my noob questions. I'm working through the thread and trying to get back up to speed on many of the things that I've forgotten.
Tonight I wired up the inductors and 5.5 ohms of resistors. Wow, what a nice change. They sound much more balanced and still have their sparkle. I was going to cut these up and build the cornu with these drivers, but not now. I have no idea how they measure, but they make me want to listen to music.
In other news, I stopped at the store and bought a new dual temp hot glue gun, long glue sticks, liquid nails, caulk, and six sheets of Elmer's foamboard...
In other news, I stopped at the store and bought a new dual temp hot glue gun, long glue sticks, liquid nails, caulk, and six sheets of Elmer's foamboard...
Yes I have!
And if You’re wanting to take it a step further, You can cover in fiberglass screen (like You use to keep bugs out of an open window) and saturate it with kills or glider gripper.
The fiberglass gives the whole thing the rigidity an enclosure needs.
It’s a viable, lightweight system that in the right place is phenomenal!
And if You’re wanting to take it a step further, You can cover in fiberglass screen (like You use to keep bugs out of an open window) and saturate it with kills or glider gripper.
The fiberglass gives the whole thing the rigidity an enclosure needs.
It’s a viable, lightweight system that in the right place is phenomenal!