I decided to document my Visaton LTS 50 experiment of two drivers here. I saw some usage of LTS50 on some full range drivers before, but all are long time ago, and without any modern drivers. So here it is.
First on some basics. Doping drivers might improve or worsen a driver. But one thing is for sure: It will decrease HF response and extension since it adds weight to drivers cone. So I will not choose drivers with limited HF extension. "Overly bright" drivers are good starting point. Better if they have shorting rings in motor, so the response will raise with frequency. I choose FF125WK because it fits these requirements and has a very high peak at 7khz. I use a modified IKEA turntable to apply LTS50 as smooth as I can:
Here's before and after:
Overall I think the coated driver looks great. Like Seas CA* coated paper drivers. Coating was easy too, use a few layers until you satisfied. And here's frequency before/after:
It's easy to see one 12db peak has now became two much smaller peaks. I think it works great. It's very obvious when the original driver connected to a noisy amplifier, you hear a SSS noise at 7khz but with the coated driver, it sounds like a white noise with even frequencies.
Next is the famous FE103SOL. Actually I was a bit nervous on coating this driver since it's a limited edition driver, but the reason is the paper cone started to develop some yellowing, and I think it looks awful. And I know how it will develop in the future. You can see the yellow stuff grown on the center dustcap, it was used to be beautiful white when new:
But apply coating on FE103SOL is MUCH MORE difficult. The "metallic eyelets" will affect coating, and the paper absorb the liquid with different rates. In the end, it's much more difficult to get an even result.
Finally here it is:
I think they looks better with actual driver, the shinny texture still looks good to me. Frequency response wise, the real improvement is driver matching. Before the pair of driver don't match quite well:
You can see these two drivers peaks and dips at slightly different frequencies, one of the reasons the sound stage is not as good as it can be. Also, the dip at 1.8khz was very significant and high-q (~6db) (Also found in hobby-hifi)
After coating:
The two FE103-SOLs basically peak and dips at very similar place. Although the curve looks a bit more "rough" than uncoated drivers. It's easier to EQ this time. The biggest improvement was the surround dip at 1.8khz. BTW I lost around 1khz high-frequency extension due to added weight, but it's still a bright sounding driver due to strong energy at 10~12khz.
With thick black coating(black is perfect for absorbing UV), and additional protection, hopefully I will no longer be bothered by aging issues of the Fostex Banana cones.
First on some basics. Doping drivers might improve or worsen a driver. But one thing is for sure: It will decrease HF response and extension since it adds weight to drivers cone. So I will not choose drivers with limited HF extension. "Overly bright" drivers are good starting point. Better if they have shorting rings in motor, so the response will raise with frequency. I choose FF125WK because it fits these requirements and has a very high peak at 7khz. I use a modified IKEA turntable to apply LTS50 as smooth as I can:
Here's before and after:
Overall I think the coated driver looks great. Like Seas CA* coated paper drivers. Coating was easy too, use a few layers until you satisfied. And here's frequency before/after:
It's easy to see one 12db peak has now became two much smaller peaks. I think it works great. It's very obvious when the original driver connected to a noisy amplifier, you hear a SSS noise at 7khz but with the coated driver, it sounds like a white noise with even frequencies.
Next is the famous FE103SOL. Actually I was a bit nervous on coating this driver since it's a limited edition driver, but the reason is the paper cone started to develop some yellowing, and I think it looks awful. And I know how it will develop in the future. You can see the yellow stuff grown on the center dustcap, it was used to be beautiful white when new:
But apply coating on FE103SOL is MUCH MORE difficult. The "metallic eyelets" will affect coating, and the paper absorb the liquid with different rates. In the end, it's much more difficult to get an even result.
Finally here it is:
I think they looks better with actual driver, the shinny texture still looks good to me. Frequency response wise, the real improvement is driver matching. Before the pair of driver don't match quite well:
You can see these two drivers peaks and dips at slightly different frequencies, one of the reasons the sound stage is not as good as it can be. Also, the dip at 1.8khz was very significant and high-q (~6db) (Also found in hobby-hifi)
After coating:
The two FE103-SOLs basically peak and dips at very similar place. Although the curve looks a bit more "rough" than uncoated drivers. It's easier to EQ this time. The biggest improvement was the surround dip at 1.8khz. BTW I lost around 1khz high-frequency extension due to added weight, but it's still a bright sounding driver due to strong energy at 10~12khz.
With thick black coating(black is perfect for absorbing UV), and additional protection, hopefully I will no longer be bothered by aging issues of the Fostex Banana cones.
Last edited:
Some ZIG 2-way glue on the back at the cone/urround interface. 2 coats. In the FF1255 dustcap a coat of acrylic gloss helps. Particularily if you put a parttern of spots in a specific pattern. I can help with that.
You have to add alot of dope to kill the HF or increase mass.
You have to add alot of dope to kill the HF or increase mass.
Hi yes, the decay on FF125wk is much improved. FE103SOL is also decays faster, but I few biggest reason is HF output being lower.
But I think, with enough resolution(no smoothing), frequency response and CSD/decay are technically the same thing. If a 12db peak is reduced to, say 10db, then the CSD must be improved. If it stores energy, it will shown on frequency response.
I tried LTS50 in the 90ies on my first loudspeakers I owned: Celestion DL4. I doped two times the paper cone of the bass and the sound improved.
I put a wooden brace in the box from left to right and put the damping - baf wadding from being losely distributed in the box to the surfaces inside allowing for airflow of bass reflex.
I changed two electrolytics in the crossovers for foil types.
Overall benefit was audible.
Hey this is long ago!
You can also try one thin coating on both sides of the driver instead of two on one side
I put a wooden brace in the box from left to right and put the damping - baf wadding from being losely distributed in the box to the surfaces inside allowing for airflow of bass reflex.
I changed two electrolytics in the crossovers for foil types.
Overall benefit was audible.
Hey this is long ago!
You can also try one thin coating on both sides of the driver instead of two on one side
Attachments
Last edited:
I think ff125wk and ff105wk are very similar. You can try. I expect damping the 7khz peak more or less like my ff105wk.