Jump to content

Fastrac Cornwall horn pros and cons


Rjk1972

Recommended Posts

10 minutes ago, Honeybadger said:

I assume this is exactly how you feel about CD horns.

Why would you assume that?

 

med_gallery_26262_6_1571719.jpg

 

These HF horns are all "controlled directivity".  However, they're not strictly "exponential" or "tractrix", but rather "modified tractrix".  All are Klipsch acoustic horns (except center tweeter).  The bass horns are exponential expansion. 

 

A more recent shot:

 

IMG_2994.png

  • Like 2
Link to comment
Share on other sites

8 minutes ago, justinsweber said:

I've owned all 3horns. If you want stock k55 the the fastrac is the BEST. Yes is sounds different... better not harmful to my earns. If you can afford he eliptr-, nothing beats it. 

 

Really?  Have you heard a pair of K-402s or K-510s set up properly?

 

Link to comment
Share on other sites

10 minutes ago, Deang said:

Don't see how that relates to the 510 and 402, which use different drivers. 

Really?

 

http://www.parts-express.com/prv-audio-adm25-50-1-3-8-18-tpi-driver-to-4-bolt-2-horn-adapter--294-2941

 

1 hour ago, justinsweber said:

If you can afford he eliptr-, nothing beats it. 

Nothing?

Link to comment
Share on other sites

This is great. Thanks for all the opinions and information. 

 

So I have a totally novice question. There is mention of a k700 horn and a K600 horn when referring to Cornwalls. What is the difference and when did they change? 

 

So it sounds like what everyone is saying is that the Fastrac Horn has a.better polar response which means it maintains its composure and holds its dispersion pattern better than the Klipsch midrange horns that come with the Cornwall. Is this correct?

 

Chris A, thanks the dumbed down detailed answer. I really appreciate it. So what is FC and is it being different going to amount to any noticeable changes. I understand some crossover changes to make the Fastrac Horn ideal. On the ALK page it is stated that the horns can be swapped with no changes but that the crossovers should be changed. Would you know of the ALK crossover addresses what is needed for the Fastrac Horn. About the 510/K69 combo. Is there anyone that makes a kit to make that swap for Cornwalls and a way to get a set of crossovers made for that setup?

 

Deang, are you the gentleman behind Althea? Do the crossovers you make address the changes that need to be addressed for different mid horns? The one for sale in the Garage Sale section looked great. 

 

Thanks

 

 

Link to comment
Share on other sites

2 hours ago, justinsweber said:

I've owned all 3horns. If you want stock k55 the the fastrac is the BEST. Yes is sounds different... better not harmful to my earns. If you can afford he eliptr-, nothing beats it. 

I thought the eliptrac wouldn't fit in a Cornwall. I was actually going to consider a different midrange driver if just the horn swap didn't get me what I was looking for.

Link to comment
Share on other sites

On 10/11/2016 at 4:39 PM, Rjk1972 said:

So it sounds like what everyone is saying is that the Fastrac Horn has a.better polar response which means it maintains its composure and holds its dispersion pattern better than the Klipsch midrange horns that come with the Cornwall. Is this correct?

I doesn't lose vertical polars at as high a frequency as the K-600, however, its horizontal polars are not something that "I'd write home about".  The K-510 is much better horizontally.

 

On 10/11/2016 at 4:39 PM, Rjk1972 said:

So what is FC and is it being different going to amount to any noticeable changes.

"fc" is a placeholder to describe the lowest effective frequency (the "cutoff frequency") that the horn+driver can support.  In the case of an exponential horn like the K-600, it is a function of the length of the horn, and it has a precise definition.  In the case of the tractrix horn, it doesn't have a precise value, but only a range of frequencies in which the horn+driver begins to lose coverage control.  The lower that frequency is, the better.  If it's close to the crossover frequency that you're using, you can have issues with both on-axis and off-axis frequency response. 

 

On 10/11/2016 at 4:39 PM, Rjk1972 said:

About the 510/K69 combo. Is there anyone that makes a kit to make that swap for Cornwalls and a way to get a set of crossovers made for that setup?

Unfortunately no.  It's more of a DIY affair.  Passive crossover designs for a couple of different 2" drivers is published by Roy Delgado (Klipsch) and I'm sure that it could be build at home...or perhaps you could get Bob Crites to build it.  It has more than a few parts in it.  However, the settings using an electronic crossover (one crossover for both loudspeakers) are available if you reconsider bi-amping them (it sounds incredible, by the way).  The costs would be significantly lower than passive crossovers of any quality.  PM me for details on electronic crossovers that would work well.

 

Chris

Link to comment
Share on other sites

22 hours ago, Rjk1972 said:

I thought the eliptrac wouldn't fit in a Cornwall. I was actually going to consider a different midrange driver if just the horn swap didn't get me what I was looking for.

 

The Eliptrac was designed for the Khorn, I think. While this is not exactly an Eliptrac, Bob has come up with another manufacturer for a 2-way design of his Cornscala:

 

http://www.critesspeakers.com/cornscala-style-d.html

Link to comment
Share on other sites

Chris, yes, I know there is an adapter that will mate a K-55 to a 510 - but I don't like adapters. 

 

If I had the money, I would very much like to try the HF-904, but it's just too much money for what it is. I can go beryllium on a different horn with that kind of money!

Link to comment
Share on other sites

  • 2 months later...
On 10/12/2016 at 3:52 PM, Deang said:

To the OP - you can run Fastracs with the stock networks. Nothing is ever perfect, but with that said, you will readily experience a net improvement in sound quality. 

Resurrecting this for a quick clarification, as I am likely embarking on this upgrade. When you say "stock network" are you referring to the B1, B2 or both?  My CW 1-1/2 gave the B2 network, which I recently rebuilt with Bob's kit.  I plan on going to the ALK Universal, but it would be nice to know if I could happily live with the B2 and the Fastrac horn (with the K-55-V solder connection driver) for a while if needed.

Link to comment
Share on other sites

That is a generous offer. I hope the OP takes you up on it. 

 

The K-510 is a great little horn that can be used in so many applications. Combine it with an electronic crossover (even an inexpensive one) and you can do some very interesting combinations and demonstrations.

 

Link to comment
Share on other sites

41 minutes ago, Coytee said:

tlarwa, where are you located?

 

If you're near the Knoxville/TN area, I have an extra K510/K69 that you could borrow for a listen.

 

(Prior version without the 'mumps')

 

 

 

Unfortunately, I'm nowhere near you (SE WI).  I'm going to do a little research on the K510/K69 now though, since I'm not up to speed...

thanks for the offer though!

So would the K510 horn mount in the Cornwall cabinet?  

Nvm ... I see pics and a new motorboard would be required.  

Link to comment
Share on other sites

On 10/11/2016 at 10:38 AM, Chris A said:

If you're talking about the Fastrac horn shown in the bottom photo below, it's basically the vertical mouth dimension that controls the frequency at loss of polar control.  If that dimension is twice the height of the K-700 horn, then it loses vertical polar control about an octave lower, etc.  That would make the loss of vertical polars around 700 Hz  or lower rather than 1700-2000 Hz for the K-700. 

 

offaxis.JPG

 

 

While that discussion wasn't part of my discussion above, one thing that you'll notice about all Klipsch acoustic horns is that they tend to expand more rapidly at the throat than a strict exponential/tractrix curve (which are the same curves at the throat end, if you look at the equations).  This is the so-called "rubber throat" of PWK that significantly reduces thermodynamic (condensation) distortion as well as generation of "frying bacon" (higher order modes) that will interact with the midrange driver up to about 8 kHz, at which point these HOMs will exit the horn mouth.  So to say that Klipsch has throat distortion and other third-party vendors' horns don't--probably isn't terribly accurate.  However, the degree of throat distortion may be lower in other horns due to a more rapid throat expansion than the K-600, K-500, or K-400 horns. 

 

 

 

So if I am reading this correctly (and I probably am not) If I were building a set of traxctrix horns should I make the sides straight and the top and bottom curved? 

 

What is a good ratio to use (horizontal to vertical) for a K Horn or La Scala?

 

Thanks. 

 

 

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...