Humble homemade Optimo loudspeaker

[supernet]

Hello.

I searched the forum and see that here should be few Optimo TL builders.

I am also interested in this project, so could please anybody who build it or heard it describe sound a little bit?

Thanks

[dublin78]

Hi
Mine are still stuck in bass reflex cabinets, and therefore have not reached their full potential yet.
The wood is ordered for the TL cabs, but I am away for a few weeks, so I can't envision completing them imminently.
I am interested to hear other's views also.
Michael

[planet10]

I have a lot of respect for the stuff Tony have done, but reading about this TL is like reading stuff from the dark ages,

It would take some modeling, but my guess is that this line is far from optimum, 1st off the cross-section is likely too small.

dave

[supernet]

Thanks for response

Firstly I though putting the SS 8531 driver into 32 L BR cab, like SP95/98 from Troels site, but then I heard a lot of opinions on BR designs that are all very similar to yours "dublin78". So I though to go TL to avoid "loudness" effect in BR box.

Dublin78 have you tried Troels series crossover from his SP95/98 design on your A.O.S. project?

[dublin78]

No I have not tried Troel's crossovers yet. I don't know that Tony's is not optimal yet.

The most surprising difference with the TL is aparently in the midrange. This is what I am hoping will be improved the most. Any change in bass behaviour will be incidental.

Planet 10: Tony's designs are well respected generally, so why don't you agree with his point of view? I can understand why you may disagree with the theory behind the Optimos, but the design was more largely based upon listening tests by an experienced designer.

[planet10]

Originally posted by dublin78
Planet 10: Tony's designs are well respected generally, so why don't you agree with his point of view? I can understand why you may disagree with the theory behind the Optimos, but the design was more largely based upon listening tests by an experienced designer.

In the last 7 years with MJKs modeling software & innummerable builds from it, the short-comings of classic TL design have been hi-lighted. This box may well sound fine, but i can't help but think it could be better. No consideration (or understanding) of how to get an appropriate length is documented, the cross-section is far smaller than would be usual for an optimum TL, and the semi-arbitrary offset of 1/3. For a 1:1 line the starting point for optimum is 0.349 and inches can make a difference.

dave

[dublin78]

Planet 10: I completely understand your point of view, and your answer was expected.
Are your concerns largely about optimising the bass performance, or does TL theory affect the midrange also?
From reading Tony's build diary, it appears that he has made a deliberate trade-off.

For now, I will be building to the existing specs, but it would be interesting to build some tests cabs to a modelled design at a later stage to see what can be achieved.

[anatole51]

Originally posted by supernet
Hello.

I searched the forum and see that here should be few Optimo TL builders.

I am also interested in this project, so could please anybody who build it or heard it describe sound a little bit?

Thanks

I built the optimo. My listening gave a sound with an open midrange and a very fine smooth treble .
The basses are very present and articulated. In comparison with a br that I also tested the midrange win in detail and opening. A speaker with a lot of smooth and spatial image amazing. I think that sings as well as Gamut L5.

[planet10]

Originally posted by dublin78
I completely understand your point of view, and your answer was expected.
Are your concerns largely about optimising the bass performance, or does TL theory affect the midrange also?

The theory considers only the bass, but experience says the bigger cross-section will help the mids even more. The better "total" function of the TL the better the mids. As i've said for 25+ years -- a good TL sucks the backwave down the line so that it won't come back thru thr cone.

It should also be noted that in Tony's empirical tests, the lines were not "tuned" the same. The tapered TL would need to be both shorter, and the offset would have to be different to maintain the same tuning. Tony 's experiment changed at least 3 variables at once which would have changed the ripple signature.

dave

[Scottmoose]

Indeed.

Like Dave, I have a great deal of respect for Tony, and I don't doubt that this design sounds decent enough. But I'm equally certain that more can be extracted from these drivers, as there is little consistancy, or science apparant in the cabinets tested. Quite the opposite in fact, as noted above.

Using George Augsperger's or Martin King's alignment tables would allow a far more capable cabinet to be created. The two sets of tables BTW correlate well, though Martin's are more detailed & refined in proportioning the line itself and are freely available on his site -see www.quarter-wave.com

FWIW, I'd probably use a 3:1 taper line, tuned to 35Hz, driver offset of 0.336 length, with Vb in proportion.