YNWaN
25-10-2013, 16:31
My most recent project has been to build a pair of add on super tweeters for my speakers. The motivation for this has been measurement that suggests the Yamaha's beryllium tweeters roll off quite steeply past 15K. Now this fact has to placed in to context that many 'middle aged' male ears are theoretically capable of hearing even up to 15K and relatively little musical information exists (or us supposed to exist) at such high frequencies.
So, I've not been exactly sprinting to take on this project; partly because I had serious doubts as to its validity and partly because I couldn't find what I considered to be an appropriate drive unit.
A trawl of UK sites revealed nothing to attract me. Ideally I wanted a ribbon, or ribbon type, drive unit that was reasonably linear to 40K. The problem, for me, with a lot of ribbon tweeters is that they are aimed at minimising their biggest limitation - and that is that they struggle to operate at lower frequencies with realistic power handling. However, as I only need it to come in at 15K that was a non problem for me. The other issue is that although most ribbons have usable output up to 40K it is often far from linear.
As it happens, almost by chance, I was looking at Parts Express (an American DIY audio supplier) and I saw they had a new tweeter - an AMT design that was very compact. I won't go in to the details now of how an AMT transducer works but although it looks like a ribbon it is not and is unique in operating principal
Well, to cut this long story a bit shorter, I purchased a pair, did a bit of crossover maths (actually, my friend Dave did it) and built little stands for them so they could sit on top of my speakers.
I fully expected to find myself removing them after a short spell of minor disappointment but in fact they have proved to be quite remarkably effective. I actually can't recommend them enough!
So, I've not been exactly sprinting to take on this project; partly because I had serious doubts as to its validity and partly because I couldn't find what I considered to be an appropriate drive unit.
A trawl of UK sites revealed nothing to attract me. Ideally I wanted a ribbon, or ribbon type, drive unit that was reasonably linear to 40K. The problem, for me, with a lot of ribbon tweeters is that they are aimed at minimising their biggest limitation - and that is that they struggle to operate at lower frequencies with realistic power handling. However, as I only need it to come in at 15K that was a non problem for me. The other issue is that although most ribbons have usable output up to 40K it is often far from linear.
As it happens, almost by chance, I was looking at Parts Express (an American DIY audio supplier) and I saw they had a new tweeter - an AMT design that was very compact. I won't go in to the details now of how an AMT transducer works but although it looks like a ribbon it is not and is unique in operating principal
Well, to cut this long story a bit shorter, I purchased a pair, did a bit of crossover maths (actually, my friend Dave did it) and built little stands for them so they could sit on top of my speakers.
I fully expected to find myself removing them after a short spell of minor disappointment but in fact they have proved to be quite remarkably effective. I actually can't recommend them enough!