having fun with the fastracks

[Daan]

Athough beeing more than satisfied with Dave's fastrack horns for my La Scala's, after a customer asked to try out a dampening-product, I just could not resist.

I took out the fastracks and started with sanding the inside of the horn since I liked the original finish, but wanted to experiment with a smoother finish.

After that I sprayed them again with satin-black paint after I removed the adapter that holds the magnet assembly. I found the adaptor was fitted with a foam layer, and that the surface where it was mounted was not in line with the mouth for both horns.

I milled that area [the backside of the horn] so it was completely in line with the mouth-area now , removed the foam layer from the adaptor, and glued it in place.

Then a layer of Dynamat was added to all sides of the horn, next a layer of underbody-coating to make it moisture-resistant, followed by a thick layer of "HELIX dampening-paste" coming from Germany [the stuff that the customer asked me to try-out for applying-purposes].

This stuff is easy to apply with a paint-brush, like a thick paste and hardens out fast without any "ugly-smelling additives".

Result is a wooden horn that now weighs considerably more than the original, sounds very "dull" when tapped, and gave me some eveings of fun, playing around with different materials.

BUT...... does it sound different...?

It does, but only at higher volumes; at soft to normal listening volumes there is no difference in sound, when playing louder "the sound just stays the same" as where voices used to alter a bit before [results from the resonances coming from the bassbin..?]

So not a mod I would recommend to everyone, unless you have too much time and some material to play around with [wink]

[Daan]

Another pic; after all layers have been added, it was time to dry in the open for some hours.

[Daan]

Milling prooved to be the answer to get a perfect flat surface and alignment of the mounting-surface for the adaptor.

[picture showing the back-end before milling] this situation was compensated by a foam layer,factory-glued to the adaptor's mounting surface; I wanted it to be perfectly flat and in line with the horn's mouth. The first pic shows the dynamat and the milled and sprayed surface, allowing me to mount the adaptor with a small amount of glue only.

[Daan]

The mouth area now has a black finish that matches the looks of the stock [aluminium] K400 horn seen from the front [bUT SOUNDS MUCH BETTER!].

Beeing very satisfied already with my fastracks, I find myself playing music with the volume somewhat louder than before, like it's got even more "ease" to keep that "natural sound" that I like so much. [K400's sold already]......My guess is that if you have a chance to hear a set of these fastracks, your K400's will end up beeing sold as well, no matter howmuch you like them [are used to them] now. Almost forgot; ofcourse I took the time to apply a perfect "square-to-round" filling in the mouth's smallest area prior to painting them for the last time.

[Daan]

Just for the record; after trying out several tube-amps, this Trends TA10.1 [which I modified with the help of Michael Mardis his website] sounds terrific!

It's a low-cost T-amp powered by the 12 Volt motorcycle-battery that I used before to power my other pre-[tube] buffer and TA2040 amp.

I feel every owner of a horn-system should try out a T-amp powered by a battery to be able to compare the foot-tapping feeling these small wonders bring into the music in combination with horns; using the advantage of the high sensitivity to let these amps shine with only 2x 10 Watts [8 Ohms].

After by-passing the [simple] volume-pot and input-lines, shielding the air-core filters, and replacing the input-connectors plus power-inputcaps with bigger and better quality ones, this truly sounds like a well-known review on the internet writes; "a match made in heaven".

http://www.6moons.com/audioreviews/trends/ta10_3.html

Just wanted to share.[]

Nico

[MechMan]

Good job...but is damping wood really nessessary?

I have a set of Daves Tractrix horns and they are amazing out of the box.[H]

[Daan]

Well, like I wrote ; it is not nessessary. Straight out of the box I was very happy with the fastracks as they were. I was just playing around with different damping materials for fun, and posted my findings, for those who were possably thinking about doing the same.

There is a lot written already about damping mid- horns, resonances from the bassbin etc. , so I will not add another you-really-must-do-this-mod.

On the other hand I'd recommend you to try out this T-amp after hearing the difference between some tube amps [used by a lot of LS-owners] because you'd experience a BIG difference especislly when it comes down to beeing lively, detailed and a 3-d soundstage. Other than that it's a amp that's cheap, small, and you can sell it again when you don't like it.....

Damping the fastrack is another story; the materials I put on there won't come off anymore, so it was a gamble what would be the outcome of this experiment; better, no effect, or worse. Place you hand on the backside of the fastrack when playing musice like drums or cello; you will understand why I wanted to try this in the first place.

Also would like to add the following; after changing from the old [sagged] woofers to Bob's cast-frame woofers, the K-77 for his CT-125 and Dave's fastrack for the K400 [aluminium ones] , combined with Bob's type-A crossover, these speakers have never sounded better.

It's just a whole different experience. I'm not the kind of owner who will change the cabinet itself, but I did try out a lot of different other things [like some more members here[].

With the ALK universal crossovers I found the sound to be more pleasant, but the speakers did not sound like horns anymore; way too laid back, and no foot-tapping anymore... My two sons of 6 and 8 years old helped me making decide which crossover sounds best; they clearly responded after changing the ALK for the type-A .....they began jumping around the room again.[<)]

So I have a pair of the ALK's UNIVERSAL's for sale.... [notice that I'm in The Netherlands....] Also my brother-in-law wants to sell his original K401's and K-77's after me installing the units mentioned above in his LS's. [All these items only interesting for European members I guess].

I hope that this helps others; I thank a lot of you for helping me find my way through all "upgrades"and "modifications"....you have no idea how many threads I have read while beeing ill for a year, those threads containing your ideas, troubles and findings....

All these threads have helped me, to find my way through what-to-do and what-not-to , since somebody here already did and found out......

So THANK YOU ALL FROM THE NETHERLANDS, hope you enjoy your horns, and how they enrich your life just like we experience it over here! []

Nico

[Guest David H]

Good job...but is damping wood really nessessary?

Dampening the laminated horn is really not necessary. Between the side laminations is an expanding polyurethane adhesive that eliminates vibations between the two surfaces. Secondly the side laminations are assebled under pressure in bending then framed to support the outer most edges of the horns that would be most susceptable to harmonic vibration. In short, Fastracs and are not very susceptable to resonance.

Although dampening the horns is not necessary, it certainly doesn't hurt anything either. I have no objections to anyone trying to better the sound.

Nico, I am pleased you are enjoying the horns and mods, keep up the good work.

Dave Harris

[Al Klappenberger]

Nico,

I suggest that you wait a while before getting rid of my Universal networks. I think you are going to find out the "jumping around the room" is not such a good thing after you listen for a while. I think this is first a impression after ridding yourself of the harsh K400 horn in favor of something better. Before, the network was helping the problem and you have discovered first hand what I always tell people, that is that changing out the horn is a much bigger improvement then the network.The artificial ambiance casued by the huge driver overlap of the A network is confusing you. Give it a couple weeks before you make a final decision. You may discover the Universal network can do more for you than just partly compensate for a bad horn.

Al K.

[MechMan]

Nice write up Nico.

I have to agree with Al on the x-overs though. Don't get rid of them too soon.

I lived with my Fastrac's and a B network for almost a year before I could afford to replace it with a universal, and to my ears it was almost as big a difference as the horn itself once I got placement correct. I have it set -12 on the horn at the moment due to the fact I usually listen loud and these have never sounded better.

A friend that has grown used to my speakers sound over the last year noticed immidiately after walking into the room the difference in the sound. Very airy with a huge soundstage. My B's just cant come close to that.

Just my 0.02 CAD

P.S.

Good luck on todays game

[Daan]

Thank you both for sharing your thoughts about this.

I have listened for about 6 months with your filters Mr. Klappenberg; it made the difference everybody describes after hearing them.

Then I removed the K400's, switched to the Fastracks and from the start found the sound to be laidback [to my ears] like described.

I ordered a pair of Bob's A-'s because I just wanted to know for sure; they sounded more "live" from the start,and after playing for about two months with one- and then the other again, I came to my conclusion.

I'll take your advice and connect them again, trying a "hotter" tap on the autotransformer and re-do the comparison.

Thanks for the thumbs-up regarding tonight's game; will the spanish, or the Dutch celebrate tonight???[<)]

Nico

[Al Klappenberger]

Nico,

Yes, the A will sound more open at low levels. It's artificial ambiance caused by major driver overlap. It's what I liken to singing in the shower. It sounds nice, but it WRONG! It will also resolve into distortion when you raise the volume. It sounded laid back because you probably had the squawker level set back to compensate for the bad k400 horn. The A network is fixed at 4-0 on the transformer. That is right in your face!

Al K.

[Guest David H]

I'll take your advice and connect them again, trying a "hotter" tap on the autotransformer and re-do the comparison.

Good plan NIco, I would try using taps 4 and 0 on the universal, because the Fastrac is not nearly as hot and harsh as the K-400. I have always had positive results with the universal crossover.

Keep this in mind while you are testing, the ear tends to favor SPL. I ran several test to prove this theory, of the six test subjects listening only Johnny 5's signifigant other called me on it. She said " they both sound the same except one is louder", the other 5 so-called audiophiles instantly assumed the higher spl sounded better. I am sure I would have chosen the spl as well.

The test was perfomed using 2 different CD players, one was the tube output Jolida, the other was ITunes playing through a Fubar DAC. In an A/B blind comparison I could not hear an obvious difference, so for the test I increased the volume on the Fubar about 1 decibel, now we had an obvious winner.

Dave.

[Daan]

They're already hooked up again and will remain there long enough to try out in the way you suggested..... Maybe I'm getting carried away sometimes because I can't sing [in the shower] myself.[:$]