An advice: SCAN SPEAK and TL speakers

[Web Wolf]

Hi everybody, I'm in point of realizing a 4 way speaker with TL bass loading I want to use all SS drivers:

Tweeter

http://www.tymphany.com/datasheet/pd...904_710003.pdf

Mid

http://www.tymphany.com/datasheet/pd...2M_4831G00.pdf

Midw

http://www.tymphany.com/datasheet/pd...5W_4831G00.pdf

Woofer

http://www.tymphany.com/datasheet/pd...2W_8851T00.pdf
or
http://www.tymphany.com/datasheet/pd...6W_8861T00.pdf

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Now question is:

I noticed that these woofers have a low Qts, so could they be efficiently loaded in a TL way ? I like very much these drivers but I must be sure that I can do the TL as I projected it.

Any suggestions ?

Bye
Simon

[sreten]

Hmmmm...........

Electronics and Acoustics engineer ?

Your bass units need to be 4dB to 6dB more sensitive than the mid.

Generally speaking lower Qts drivers need to be used reflexed.
In a TL the low amount of damping required to bring the bass up
generally causes problems with dips in the upper bass, damping
the upper bass effectively kills the lower bass.

3.5 way is the sort of thing you need. e.g. :

http://www.troelsgravesen.dk/8543.htm

/sreten.

[Web Wolf]

First of all, building loudspeakers is only an hobby for me. I usually spend my time in ambiental acoustics and architectonics.

If you are speaking about correct alignment of SPL, this is not a problem because I'll use compensation resistors to reduce SPL of upper ways. Different is the speech about the woofer.
Do you think a Morel would be better than a SS for TL or I've to make do with a "simple" reflex?

[Web Wolf]

up

[Jussi]

I'm not familiar with TL cabinets but I started wondering your driver selection. 1" dome, 4" uppermid, 5" lowermid and 8" woofer. So a 4-way with very similar size drivers. Personally I'd expect 4-way to reach all the way from top to bottom and have proper drivers for each range. How did you come up with these? Just because all of them are from SS?

Jussi

[Web Wolf]

Yes and not . First of all I love very much the SS sound because it seems very soft and smooted and then because I have watched the SPL curves given by SS. I thought that I could substitute the midlow with the 18W/8543-00 (SS of course ) loaded in a sealed box and then using a real woofer for the TL. I wanted to load a woofer in TL and cut it to 100 or 200 Hz with the crossover to avoid the upper frequencies. The problem is that I need a subw with a good Qts and a low Fs. What about a SEAS W21NAL ?

I've seen several TL articles (M.J. King in primis) and I've the simulation software but this is my first TL system and so I have to solve some problems.

Another thing: how could I know the fibers diameter used nin the pipe (required by simulator) ?

Thanks

[Misa A.]

Web Wolf,

I think I must share with you my experience.

a couple of years ago I built a pair of TL speakers with SS 8545 and SS 9500 in MTM configuration, a-la Thor, folded tapered TL, 115 cm high. I made some optimizations with King’s mathcad worksheets and was full of good expectations.

Now I am building a new pair of bassreflex TMM speakers with these drivers, after I threw away the TL cabinets when I finally gave up trying to make them sound according to my taste.

Not so long ago I built a pair of bassreflex TM monitors with the same drivers, and I was amazed by how well they play bass, very articulated and extended. Just before the monitors I built a subwoofer with the Peerless XLS12 & PR, and was going to use it to aid my monitors. Now I don’t use it at all for music because it only makes it worse.

I found the sound of my woofers in the TL enclosure boomy, and to get rid of it I had to dampen port output to the point of killing it, and turning my speakers into closed box, which I did not wish. Make a quick simulation of your woofer with MathCad and you will see that your TL creates output not only in the range where SPL of your woofer starts to incline, like a normal bassreflex cabinet, but equally adds up to at least 100-120 Hz, and you don’t need it with such woofer. All this applies, of cause, to the design I used and reasonable size of cabinets.

Best regards,
Misha

[ermes]

web wolf,
i suggest you to keep more experience on loudspesler design before use ss drivers,they want expert designer.

i've projected many good sounding loudpeakers with ss drivers but before i have done a lot experience on cheaper drivers

if you want measured datas to import in your simulation software,send me an email.
i hope to help you with them.

b.r.

[PWatts]

TL's are probably the alignment with the most "black magic" I've ever seen. Often no matter how much you try and if all the math seems in order, the result just sounds unacceptable.

My advice would be to buy a woofer that would work well in TL as well as BR, and build a test enclosure just to see how well it works.

As a side note, the best performance I ever got from a TL was with the SS 18W/8543 woofer. In a BR configuration it sounded good, in sealed it had no bass at all (as would be expected with that woofer), but with a TL... my oh my, what a difference and with a low-end extension I never thought was possible with that woofer's T/S specs. Not too well suited to HT though, and I'm still kicking myself for ditching those large 2-ways in favour of a new BR design with more drivers and higher efficiency. The SS 8542 yields very much the same performance with the difference of a paper cone.

A SEAS W17EX001 (the glass-fibre Excel model) on the other hand sounded horrible in a TL, and did wonders in a BR.

The dual W18E001 in the Thor didn't impress me at all, with woolly bass that didn't appear to go low. In fact I don't think I've ever heard an Excel driver sound good in a TL, at least not as good as they can sound in a proper designed BR.

SS 18W/8545 can sound good in TL but needs some experimentation to get right, and doesn't necessarily sound better than in BR. Some of the newer Revelators apparently deliver good results in a TL but I've never heard any personally.

I once saw a sub called the Perfectionest Audio Subwoofer that used two the KEF B139's in a dual-line TL that was nothing short of amazing. It was one of the best subs I ever heard with the exception of possibly the REL Studio, and since the B139's aren't too expensive, well worth looking into. Freq cutoff was 10Hz @ -8dB.

[Misa A.]

PWatts

Freq cutoff was 10Hz @ -8dB

And the size of that subwoofer? Just curious..