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-   -   Horn + TL Project combined (http://www.diyaudio.com/forums/full-range/92087-horn-tl-project-combined.html)

Sky_Knight 12th December 2006 11:22 AM

Horn + TL Project combined
 
2 Attachment(s)
Hi there guys :)

It`s my first post here and I need some advice about a project that`s currently "under development". It`s an idea that occured to me after I made a horn project for the Visaton FR10 driver (the project wasn`t mine, it belongs to Daniel Petrov, from a bulgarian forum). Since it has great sound (for my taste of course) and the only thing it lacks is (as usual with horns) - low frequency coverage. So I thought it would be great to combine this fullrange speaker with a low freq driver - to let the full range do all the job and the low freq driver to play all frequencies below 300-400 Hz... So I`ve started planning and came up with the following.

A small horn, which is 35x20x20 external dimensions, which I wanted to play all frequencies above 300 Hz. Of course I don`t want to use a filter so I`ve tried to make the design in way, which it could filter those lower frequencies. And... the prototype.. was actually a succes. It plays quite equal all frequencie from 300 to 17000 Hz (I don`t want to go any higher - I don`t hear it... ;) ) And everything under 300Hz is almost unhearable. And that`s about it.

Check out the small drawing I made using Paint (I usually use pen and paper, so don`t blame me for the lame drawing!)

And if you have any advices, thoughts, opinions and etc. - write them. Right now with a friend of mine we`re working on the filter which we`re going to use. Oh, and the low freq driver is Visaton W170S. It has suitable parameters...

Basically the project is:
Visaton FR10 - 4 om
Visaton W170S - 8 om
with a low freq filter for W170S and
in a Horn with TL combined construction.

Thanks for any help guys! :)

Scottmoose 12th December 2006 11:41 AM

Fair enough. Of course, we can't blame the horn for a lack of LF -the FR10's Fs is up at 97Hz, so it's never going to be a bass champ, whatever you do with it. Combining with an integral TL seems a good idea IMO. Without specific dimensions it's difficult to comment upon what could be done to improve things -still, if you're happy with it, that's the aim after all! If you haven't already, I'd advise a read of Martin King's math at www.quarter-wave.com -many people don't realise that the tuning frequency of a TL is a function of both length and taper, not just length. If you selected a tuning frequency, and then /4 to get length, in this case, as your line is tapered, it will actally be tuned lower than intended.

Sky_Knight 12th December 2006 01:27 PM

@Scottmoose

I didn`t get into more details about the TL construction, because there is already a project (a fellow from the bulgarian forum) for a TL with W170S, his line is tuned for 36 Hz, which for this driver IMO is not a good idea. I`ve already read Martin J. King`s work. I only regret that I have the oldest versions of his models, because there is no way to pay him the asked fee, and it`s not because I don`t want to - it is quite impossible to do it from Bulgaria to US... Anyway. In a couple of days I`m going to make I bit more detailed project with measurements, angles and etc.

Basically I wanted you opinion on the whole idea TL + Horn in one single construction.... And if you can give me an advice about the filter for W170S, cause we`re stuck right now...

10x for replying :cheerful:

Sky_Knight 15th December 2006 01:32 PM

Ok, so that project appeared to be a ... well.. not quite possible. We`re stuck with the filter for the woofer. It seems a bad idea to do a crossover at 400 Hz... If you have any suggestions... :( And about the TL, it can go down to 47 Hz with the Visaton W170S. And a couple of friends said, that the idea of putting a horn and a TL construction in a single construction is sort of stupid and won`t work... So without their support I`m off the project for now... :(

gmilitano 15th December 2006 02:01 PM

How about putting the full range in a sealed portion of the enclosure and use a TL for the lower end response.

Pano 15th December 2006 07:46 PM

Quote:

Originally posted by GG
How about putting the full range in a sealed portion of the enclosure and use a TL for the lower end response.
Yeah, that's what I thought. Why not put the FR-10 in a sealed box, if you want to go down to only 300Hz? Then use the TL for the woofer.

And isn't the taper on your TL backward? But I don't know much about TLs.

Sky_Knight 15th December 2006 08:12 PM

I already did test that possibility. I have a sealed enclosure for the FR10, but it doesn`t sound so light, and doesn`t have that same spacial feeling, that the horn has. And about the taper - it`s just a sketch - not a real project. And yes it`s getting narrower in the end. the mouth is equal to the Sd. And the space right behind the speaker is 1.7*Sd... The offset is 20 cm... I`m still running some tests. So these are not final numbers.

But as I said - the problem is not about the construction. It`s about the passive filter for the woofer. Right now I`m considering to change the driver - instead of W170S, to use W200S - it doesn`t have these peaks from 15-20db like the W170S in the mids....

Geoff H 17th December 2006 03:07 AM

Sky_Knight, from what I can see, you only need the one driver. You are not after a big bass sound, or are you?

A front firing w/r with a rear loaded T/L horn should do the job.

Either way, the crossover is the last thing to consider. If you do go 2-way, the crossover should simply couple the 2 compatible drivers.

The idea of multiple systems in one cabinet has a lot of merit, and has been around for a while. 2 (or more) T/Ls combined in one cabinet may be a way of reducing comb effect.

The suggestion of running a wide range in a sealed enclosure, with assistance from a bass unit to fill the lower end has loads of potential, and can be very pleasing. Not about to change mine.

Geoff.

MJK 17th December 2006 11:25 AM

Quote:

2 (or more) T/Ls combined in one cabinet may be a way of reducing comb effect.
You lost me, what did you mean by two TLs combined in one cabinet?

Geoff H 17th December 2006 01:09 PM

Hi Martin, if the top driver were to fire into a t/l also, there may be an advantage, if the system resonances were such that when the outputs were combined, the freq res would be flatter. The Z curve would have 4 peaks of lower amplitude.

EG if the lower resonance f of the shorter line was placed midway between the resonances of the longer line. And of course finding suitable drivers could be a problem.

Also, I am not sure what effect, if any, the two ports may have on each other. Some frequencies may cause them to go out of phase, negating the whole excersize.

Any thoughts?

Geoff


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