Tweeter on top?

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OK, so I have been working on plans for a summer build....and scaling back a bit as more things have been harshing my mellow--like car repairs and the need to replace a furnace. :mad:

I had been thinking of a BIB using FE208eS with FT96H. Now I'm thinking of designs using the FF225wk and a tweeter. It looks like one of the more popular choices to top off a SFRD is the FT17H; but then I search here and find some comments that the FT17H isn't all that great-- although most comments have been positive. So now I have doubts...

I think I need something much better than the cheap piezo lemon squeezer, but how much better? Fostex has some VERY nice tweeters,, starting with the FT96H and going up rapidly from there. Or is the FT17H really good enough?

Then there are other possibilities: maybe something like the Morel CAT378 (a dome in a short horn). This has the advantage of a very low f(s) at 700 Hz, so a 1st order XO around 8K Hz should work well; and sensitivity is the same as the FF225wk.

This is new territory for me. Can't afford to just buy one of each and keep trying until I find the 'best' one-- esp. since there is no best!

Would anyone care to enlighten me?

Thanks, Jim
 
Jim,
As you are thinking about a two way, might head over to the multi-way forum where I will then suggest anything less than a mid-range Seas has too much distortion and how the FF225 is more suited to a 2K crossover as most of what you see in the published charts above that is breakup and distortion.

Unfortunately, you just can't make a cone light and rigid enough to be a high fidelity full range. No one has ever done it as much as we wish they could. The old decade rule still stands. Even my Fountek 88's I wound up crossing over at 3K by the time I was done. My Fostex I dumped. 150 to 3K. Not much past the decade.
 
tvrgeek,

No way I'm crossing at 2K. I leave that to the multi-way devotees. Most of my builds are SFRD. And I like them. I did one 2 way: the MJK passive OB with FF85K and Alpha 15a with XO at 500 Hz. Just wanting to try a larger driver which I know will need help up top. Not looking for the high SPLs that multi-way guys seem to demand.

Cheers, Jim
 
Been there, done that. I have a published speaker with the FF225WK and the FT17H both mounted on the baffle. Works OK, but the phasing issue is untenable. My recommendation is to top mount the tweeter and point it toward the front wall, a corner, anywhere but at the listening chair.

Bob
 
Unfortunately, you just can't make a cone light and rigid enough to be a high fidelity full range. No one has ever done it...

It only takes one counter-example to disprove that :) Nothing is going to get the FF225 to sound as good in the treble as a really good tweeter. So it might be the worst example from which to generalize.

It's much easier to start with a small driver, and then add bass. There are definitely drivers which can do 6+ octaves, or roughly two decades. And while they are few and far between, they do exist :)
 
It only takes one counter-example to disprove that :) Nothing is going to get the FF225 to sound as good in the treble as a really good tweeter. So it might be the worst example from which to generalize.

It's much easier to start with a small driver, and then add bass. There are definitely drivers which can do 6+ octaves, or roughly two decades. And while they are few and far between, they do exist :)

OK, let's start with that really good small driver you suggest, Then add helper Bass. OK, a two-way. Now they need a bit of help in the treble. Three-Way. Oh gee, still need a sub. FOUR-way.

I understand the desire to get the crossover out of the critical hearing range. I am all for it. I also understand the desire to use lower order crossovers. Unfortunately, I have yet to find ANY driver that I can call a full range that needs only "helpers" crossed over outside the critical hearing range. I don't need high SPL as I still have my hearing. I need very low distortion.

Let's break it down.
30 to 60 or so, you need to push BIG air even for quite music. I run a pair of 12's as my subs. Even background music seems flat to me without the lowest octave. If in a multi-way cabinet, these could make it to 200 just fine. So call that 20 - 200. A decade. A few can do 30 to 300 which would help the woofer quite a bit, but My Peerless won't go that high.

60 to 600 is easy. Lots of 6 inch drivers that can keep the distortion down and are very smooth. If we are going with the big floor standers, maybe we can go to a smaller mid-bass that can push a little higher, but there is so much energy in the 600 range, you still need a decent size cone to keep the distortion down. Make the cone rigid enough for bass distortion and you get breakup issues too close on the top. 1200 seems about how high we can push a mid-woofer to be really happy. Yes, we are forced to push them to 2600 or so for most "monitor" 2-ways.

Would it be fantastic if we had a tweeter that could get down to 1200? None I know of. A 1 inch tweeter seems to be able to get down to 2500 or so and that is with pretty steep crossovers. Right in the critical hearing range. A three inch mid does fine at 1200, but every one I have tried has breakup and distortion issues long before it clears 5k.

Truth of it is, even though a crossover at 2500 is right where we would rather not have it for our hearing, drivers can be made that work reasonably well there if you know how to build a crossover. The result can be very very good. Better than any compressed driver I have found so far that could span the critical range itself. Show me that 600 to 6K driver that I can call a decent midrange. I have been looking for 30 years. I tried these "full range" drivers and found they had so many compramizes trying to make them wider range the result was untenable. No amount of exotic triode or FET amp will change that.

I won't ask for that 80 to 8K we might actually cal a full range for apartment dwellers who lost all their hearing at Who concerts, ear-buds or in the Army. Physics says they just won't work.

There is one exception to all this. My Grado's are pretty well full range.:D
 
One issue here. This is the forum for wideband drive units. If you don't care for them, fair enough, not everybody does. Personally, I like wideband driver based and multi-driver systems, usually (though not invariably) for different reasons. Either way though, this does not seem to be the appropriate place for you to hold forth on your dislike of wideband drive units.

Incidentally, I can think of several excellent 2-way systems employing dome tweeters with XO frequencies considerably < 2KHz. Zaph's BAMTM (LR4 at 1.45KHz) immediately comes to mind as a rather well known example.
 
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It will not be perfect but an FF85WK with a helper woofer or an FF105WK with a subwoofer should work alright or just be happy with the FF105 and live with it's compromises. Bigger is not always better. Large drivers move more air but sound fat and flabby. All speaker systems are compromised and most I have heard are pretty poor sounding but high quality drivers implemented properly in good cabinets will rarely disappoint.
 
OK, let's start with that really good small driver you suggest, Then add helper Bass. OK, a two-way. Now they need a bit of help in the treble. Three-Way. Oh gee, still need a sub. FOUR-way.

The part you're missing is that a wideband with a woofer is still a wideband design. This forum is mis-named and hence the constant confusion on the part of multi-way folks (not your fault, either).

Would it be fantastic if we had a tweeter that could get down to 1200? None I know of.

You're still coming at this from a multi-way perspective. Every small widebander is a tweeter. So no, an actual tweeter will not get down to 1200, but a small widebander can work up to tweeter territory (because it is one, albeit wideband is a special kind).

Truth of it is, even though a crossover at 2500 is right where we would rather not have it for our hearing, drivers can be made that work reasonably well there if you know how to build a crossover. The result can be very very good.

Absolutely true. It's a different approach than wideband but of course it can work.

Show me that 600 to 6K driver that I can call a decent midrange. I have been looking for 30 years.

Personally, I'm using the FE103En and to my ears, it beats the dozens of others I've tried. But if you're not willing to accept any breakup, then you are basically rejecting the wideband approach, which is perfectly fine. Everything's a tradeoff.

I tried these "full range" drivers and found they had so many compramizes trying to make them wider range the result was untenable. No amount of exotic triode or FET amp will change that.

Well, you are another victim of this popular but incorrect term "full range." Also, I suspect that you are as sensitive to breakup as others are sensitive to crossover issues. PIck your poison, basically. Personally, after years of looking, I finally did find a wideband + SET which totally works for me, although my system might be a complete joke to others. Certainly it has both "magic" and real limitations (no rock, no orchestral, moderate SPL's, limited dynamics etc. but oh-so-addicting otherwise).

Physics says they just won't work.

This I take to be your rejection of any breakup, so it's perfectly okay to rule out wideband for your purposes.

There is one exception to all this. My Grado's are pretty well full range.:D

See, you just undid your argument there :)
 
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Been there, done that. I have a published speaker with the FF225WK and the FT17H both mounted on the baffle. Works OK, but the phasing issue is untenable. My recommendation is to top mount the tweeter and point it toward the front wall, a corner, anywhere but at the listening chair.

Bob

Thanks Bob! That is the kind of useful information I can use!

tvrgeek,
I understand that you loathe and despise the kind of speakers I (and others here) build. But calling my babies ugly isn't helping me...

Cheers, Jim
 
Would it be fantastic if we had a tweeter that could get down to 1200? None I know of. A 1 inch tweeter seems to be able to get down to 2500 or so and that is with pretty steep crossovers. Right in the critical hearing range. A three inch mid does fine at 1200, but every one I have tried has breakup and distortion issues long before it clears 5k.

Truth of it is, even though a crossover at 2500 is right where we would rather not have it for our hearing, drivers can be made that work reasonably well there if you know how to build a crossover. The result can be very very good. Better than any compressed driver I have found so far that could span the critical range itself. Show me that 600 to 6K driver that I can call a decent midrange. I have been looking for 30 years. I tried these "full range" drivers and found they had so many compramizes trying to make them wider range the result was untenable. No amount of exotic triode or FET amp will change that.

I won't ask for that 80 to 8K we might actually cal a full range for apartment dwellers who lost all their hearing at Who concerts, ear-buds or in the Army. Physics says they just won't work.

Due to this I designed my own 8" with full range 20 - 20000 as the goal,
but there are no breakups of the cone thus the result was limited to 20 - 10000.

Then I built my AMTs that do 100 - 20000...
They need a 6dB crossover at 300 to 500 to play 120dB SPL with only one AMT.
 
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Well, you are another victim of this popular but incorrect term "full range." Also, I suspect that you are as sensitive to breakup as others are sensitive to crossover issues. PIck your poison, basically. Personally, after years of looking, I finally did find a wideband + SET which totally works for me, although my system might be a complete joke to others. Certainly it has both "magic" and real limitations (no rock, no orchestral, moderate SPL's, limited dynamics etc. but oh-so-addicting otherwise).

Rjbond,
What is the setup you are using that is addictive? I am not sure what all the fuss about cone break up is. Good thing I don't know what it is otherwise I might hear it. ;) The best part about full range is the imaging and sound stage that you can't get with multiways and their inherent lack of phase coherence. Doesn't really matter for big orchestral stuff or rock anyways.
 
Hi xrk971,

I have two systems, each does something right. The wideband is a Fostex FE103En + little 2-watt Bottlehead SET. The tone is perfectly right. It's hooked up to the TV for mini-HT duties, and it never fails that someone freaks out when a doorbell, cell phone, knocking etc. is on the show -- people swear it's real and go look outside the door, or check their phone, etc.

But this system doesn't do orchestral, rock, nor (for some strange reason) the raspy, somewhat ugly trumpets on certain old Frank Sinatra records.

The other system is a Klipschorn-style horn system, and when it plays Stravinsky, you might swear you were there. I can switch out the midrange/tweeter for a widebander on a 1-meter diameter 160Hz horn which has certain other charms.

The issue with breakup is just that a driver will work like a piston for part of its range, then transition to non-pistonic at higher wavelengths. Some drivers (like the FE103En) have a dome-shaped dust cap which effectively makes it a dome tweeter. The cone's profile is shaped in a way that permits wide dispersion (unlike, say, a wider, deeper driver which would beam more).

So in between the piston range and the dome tweeter, the behavior might be good or bad, flat or ragged, sweet or horrible. It's similar with whizzers -- some are good, some not so good.

My main quibble is that people come to the forum already disadvantaged by the term "full range" which means that they have to un-learn a lot of myths. We could shortcut that process for them if we switched to the proper term wideband :)
 
augmented fullranger...

...such as a Tysen boxed/augmented bass system (planet10's design), Dick Oshler's Basszilla design OB/augmented bass(which are incredible but quite expensive to build, so similar using more economical drivers) or Stereo Sound "Tube Kingdom" OBs with a good (and large) fullranger and tweeter (HF augmented) mounted coaxially (mine use salvaged Oxford J10s and Vifa tweeters, crossover is a 12dB/octave). All are dependent on your room size , budget and amplification.
 
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Rjbond,
thanks for the description - sounds like two very nice systems that do what you need. I have heard a lot of good things about the FE103En... So you are not using any helper woofers with it at all? The 1 meter dia horn is good if the room and WAF allow it :) The term Wideband is more accurate - probably why the Tang Bands all start with "W".
 
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