Fast, fun, Inexpensive OB project

[mige0]

Hi


Thanks for all your positive comments!
Took some time - had to finish my amps PSU tweak first.



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Originally posted by panomaniac
Hey Michael - that's great!

I'd love to hear your version, but the hills of Austria are just a little too far from the hills of Hawaii. =)


Nice work. And thanks so much for the graphs and measurements - they go a long way to explaining what is going on. What is the crossover software you use?

I'm suprised at how flat you got it. Just seems to be a peak at 3Khz. Cone break-up? Baffle nasties?

My main question would be this:
Given that your measurements show flat (more or less) at 1M in front of the baffle, do they not sound too bright in room? Is there a lot of mid energy coming off the back of the Peerless and filling the room?

The original pair have a big midrange dip in the crossover to counter the midrange energy coming from the back. I see that your soft crossover does the same thing, but the resulting FR looks a lot flatter than I would have expected!

Thanks for pursuing this fun little speaker. Maybe it will encourage others to give it a try.

Paniomaic, the plots shown in my last posting are " in room " measurements. They show what the speaker does AND what the baffle does AND what the room does at a SPECIFIC position of the speaker AND the mic.
Please don't interpret too much from them. It wasn't meant to be scintifically but just to have a good startoing point for own experiments on a active setup with the Behringer DCX2496.
It shows that there is relative good balance obtainable with not very much effort. And that the original XO can be translated to active amping with remarkable little change.

It was a "quick and dirty" setup though, within half a day – included buying the material and producing some sawdust - heavily based on measurement and not so much on listening. Though it turned out pretty well, everybody is invited - and actually SHOULD – tweak it to his / her taste.

The brightness expected isn't there, maybe the result of the rear tweeter ( IMO its ALWAYS of benefit so I didn't even try without ) but the tweeter for me was too early unless I delayed it.

Originally posted by terry j


Hi michael, could you (and others) comment on this please. I'm curious about using white/pink noise when setting up speakers to be flat.

Basically, when do we use which?? They are very different sounds, and so when we make the speaker flat on each, well they will sound very different won't they??

Additionally, what is the difference again if we use a swept signal?

..........

TerryJ, the stimulus depends on the measurement used.
For a RTA you use pink noise to get flat reading, for FFT you use white noise for flat reading ( be aware not to overload the tweeter ! ).

Usually FFT is NOT used without windowing but you can do so and basically you get whatever is in your room at the place of the mic.

Swept signal is a good stimulus for distortion measurement at close micing. I don't use it for FR measurement.

Originally posted by Bratislav


I was curious about this too, and your guess is spot on. Would experimenting with baffle edge (making it progressively narrower, to a point) help, or should we attack it differently (moderate Q anti resonant LCR targeted at 300Hz) ? I'm extremely intrigued by this development as I still like the idea of multiple SLS's on a large-ish baffle as bottom end of a Arvo/R909 like 'clone'.

Bratislav

Bratislav, no need for correction at 300 Hz - its an artefact.




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I did some FFT measurements that exclude the room.
Naturally it reveals a lot of details one normally doesn't like to see, though we have to keep in mind that a good looking FR has NOTHING to do with good sound from a speaker.










This plots show the Peerless SLS12 without XO but with the high shelfing EQ.
What can be seen is that there is NO stored energy at 300 Hz. Though the window used limits the valid FR range to above 300 Hz – indicated with the yellow bar at the X-axis – we would see a severe peak for sure.

What jumps into the eye are the resonance in the cone break up region.




Greetings
Michael

[mige0]

Hi


For those who have a DCX and would like to give that nice design a try here is the setup for kind of improvement in the cone brake up region.
Though my impression is that you trade in slight refinement in terms of imaging and tonality against unique character and fun factor.







A setup file for the Behringer DCX that you can downloaded from my site :
http://members.aon.at/kinotechnik/di...ium_tweak4.xpc










The EQ'd Peerless rolls off more early and this has to be compensated by a lower XO frequency for the tweeter at around 1100 Hz or so.
Again its only meant as a good starting point for own experiments.

It would take a LOT MORE time than I had to provide a really sophisticated XO / EQ tuning to bring out all the strengths the Manzanita 12s is capable of and I am quite sure the original passive setup still is superior in this respect.

Greetings
Michael

[Pano]

Thanks Michael for posting your results. Very encouraging.

So those are screen shots of the software interface to the DCX2496? I've used the DCX, but never the software. Looks very handy.

Originally posted by mige0
The brightness expected isn't there, maybe the result of the rear tweeter ( IMO its ALWAYS of benefit so I didn't even try without ) but the tweeter for me was too early unless I delayed it.

As orgianlly built, there is no britghtness, unlike a lot of full range speakers. Good to know that your different tweeter gives you good results, too.

Not sure what you mean by the "tweeter was too early." Do you mean the front facing or rear facing tweeter? The passive crossover design takes the driver alignment into account by spreading the LC values a bit, so some delay on the active crossover would make sense. But if you mean the rear tweeter, then that's another matter.

[terry j]

Originally posted by panomaniac
Thanks Michael for posting your results. Very encouraging.

So those are screen shots of the software interface to the DCX2496? I've used the DCX, but never the software. Looks very handy.

I had someone setup a dcx in my system, using the buttons on the front panel. Talk about a nightmare to understand.

However, using the interface on the computer it was as simple as pie, very easy to grasp and understand.

You can download it and just muckabout (no unit hooked up) and get a feel for it, very much recommended.

thanks Michael for the explanation.

[mige0]

Hi

Originally posted by panomaniac
Thanks Michael for posting your results. Very encouraging.

So those are screen shots of the software interface to the DCX2496? I've used the DCX, but never the software. Looks very handy.





As orgianlly built, there is no britghtness, unlike a lot of full range speakers. Good to know that your different tweeter gives you good results, too.

Not sure what you mean by the "tweeter was too early." Do you mean the front facing or rear facing tweeter? The passive crossover design takes the driver alignment into account by spreading the LC values a bit, so some delay on the active crossover would make sense. But if you mean the rear tweeter, then that's another matter.

Panomaniac, yes the Millenium works well, though probably the Seas 27TDFC might blend even better – do not know. Its pretty close in data and FR only slightly less excursion.

http://www.bmm-electronics.com/docum...seas\h1189.pdf
http://www.bmm-electronics.com/docum...s/t25cf002.pdf


You can vary the phase by tweaking the XO but sound wise its not exactly the same as delaying the tweeter. At least this is my impression.

The rear tweeter is not dominant, its ~ 3-6 dB down in SPL and just there to illuminate the room. Better stage and more natural ambience are my findings here.

Originally posted by terry j


I had someone setup a dcx in my system, using the buttons on the front panel. Talk about a nightmare to understand.

However, using the interface on the computer it was as simple as pie, very easy to grasp and understand.

You can download it and just muckabout (no unit hooked up) and get a feel for it, very much recommended.

thanks Michael for the explanation.

Spot on! Its a pain to do all manually.
I made the my DCX setup file available to give a VERY quick entry to what I did for everyone interrested.



Greetings
Michael

[planet10]

Originally posted by panomaniac
Felt rings on the tweeters.

These have a circular central cutout... not the bestr shape. You'd do well to incise a star -- even just 3 points (i like 11 & 13) -- for much wider distribution of the srface wave off the inside of the ring.

Something like this:



dave

[planet10]

Originally posted by peterbrorsson
Look at Dave-Planet10's "black" coated FE127. I'm 99% sure it's a dye involved. Correct me if I'm wrong, Dave!

It is vintage black Peerless fountain pen ink, It is a very dark blue. I'm going to try black food colouring if i can find some.

dave

[lovechild]

hi panomaniac,

nice OB design! Did you ever think about using a waveguide with the tweeter?
I'm using a seas 27TDFC/TV in the Monacor WG-300 (7" waveguide), the directivity works pretty well with 8" and stiil with 10" woofers, I haven't tested 12" yet.

Here two quick and dirty graphs of the tweeter without and with waveguide in a small testbaffle (~14" x 11.5")

without waveguide


with waveguide


edit: 0°, 15°, 30°, 45°, mic distance round about 30"

cheers,
LC

[MisterTwister]

has anyone tried to remove dust cup and put phase plug in SLS 830669 ? I've done it successfully with cheap drivers, but hesitate to do it with brand new 70 dollars woofer

[Pano]

Originally posted by lovechild
nice OB design! Did you ever think about using a waveguide with the tweeter?

Thanks LC. It's a great sounding design. Wish I could take credit for it, but all I've done is document it. =)

I don't know if a waveguide would be much help in this design. The tweeter has to be padded down so much that the gains might all be traded away. (Not if bi-amping). What advantages other than efficiency gain do you find with the wavegude?

Originally posted by MisterTwister
has anyone tried to remove dust cup and put phase plug in SLS 830669 ?

That would be a big phase plug! Might be worth a try, but I'm like you - don't want to be the fist to try it....