ScanSpeak 10F 8424 PVC pipe WAW / FAST

I set up the ScanSpeaks with my Dayton R255s

[IMGDEAD]https://i455.photobucket.com/albums/qq271/tilroh/phono/ScanSpeak%2010F%208424%20woofer%20XO%20-%201_zps94eeq9qo.jpg[/IMGDEAD]

Connected the AMPs via the $30 active XO set to 350Hz.

[IMGDEAD]https://i455.photobucket.com/albums/qq271/tilroh/phono/ScanSpeak%2010F%208424%20woofer%20XO%20-%202_zps4lqigqxf.jpg[/IMGDEAD]

The music is kinda thin. The PVC pipes are stuffed with Dacron pillow stuffing and the backs are open.

Below are measurements with only the woofer and only the SS.

Woofers only:

[IMGDEAD]https://i455.photobucket.com/albums/qq271/tilroh/phono/350hz%20woofers%20only_zpsdfzimtjf.png[/IMGDEAD]

ScanSpeaks only:

[IMGDEAD]https://i455.photobucket.com/albums/qq271/tilroh/phono/350hz%20mids%20only_zpsosullxyk.png[/IMGDEAD]


Do the graphs suggest more or less stuffing? Closing the back of the pipes?

Is there enough data here to make any observation?

Thanks, Mack
 
Very nice concept Tilroh. You are in the verge of a great speaker but just need to do one thing: add a rectangular or trapezoidal baffle to the bezel of the 10F. As is, a circular driver on the end of a pipe is the *worst* possible configuration for bad diffraction effects as shown in your measurements. The 10F is about the flattest response driver available and the round pipe has made it have 6 to 10dB diffraction ripples.

Something like a simple 12mm ply board 9in tall 7in wide at bottom and 4in wide at top with 10F in middle will smooth all those ripples out.

If you look at Sigfried Linkwitz's Orion's or LX521 you will see the drivers housed in a supra baffle with trapezoidal nature for this reason.

More info from the master himself :

Diffraction from baffle edges

Regarding stuffing - moderate amount to reduce back reflection is enough. If you have impedance sweep add enough stuffing until peak is squashed half way.

Nice XO - please provide link.

Thanks for the nice work on this.

Ps, I assume the FF105WK's are from the another FAST incarnation and not part of this speaker?
 
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Very nice concept Tilroh.

You are in the verge of a great speaker but just need to do one thing: add a rectangular or trapezoidal baffle to the bezel of the 10F. As is, a circular driver on the end of a pipe is the *worst* possible configuration for bad diffraction effects as shown in your measurements. The 10F is about the flattest response driver available and the round pipe has made it have 6 to 10dB diffraction ripples.

Something like a simple 12mm ply board 9in tall 7in wide at bottom and 4in wide at top with 10F in middle will smooth all those ripples out.

If you look at Sigfried Linkwitz's Orion's or LX521 you will see the drivers housed in a supra baffle with trapezoidal nature for this reason.

More info from the master himself :

Diffraction from baffle edges

Regarding stuffing - moderate amount to reduce back reflection is enough. If you have impedance sweep add enough stuffing until peak is squashed half way.

Nice XO - please provide link.

Thanks for the nice work on this.

Ps, I assume the FF105WK's are from the another FAST incarnation and not part of this speaker?




Thanks XR, it's certainly not my concept. I believe it's your's among others. I just read the forums and copy :)

I'll get baffles cut next weekend and measure again, Thanks.

I've ordered 3 custom "HIFI Electronical 2 Way Crossover PCBA ClassA Power Linkwitz-Riley filter"s from Wastio

Tell'um where you want the XO set and wait 6 weeks.

I change out the OpAmps for "TI Burr-Brown OPA2604AP OPA2604 Low Noise" effectively doubling the price of the OX. It probably makes no difference but I think it does.

The speakers in the background are FF165WKs in B.Brines's M12-F165 cabinets. I paired these with the R225s Xed at 80Hz. The M12-F165s didn't really benefit from the woofers.

Thank you and Onward!
Mack
 
I do indeed use 10F/8424 and RS225 in a FAST but my point was not to use a round driver on the end of a pipe. I don't have a driver on the end of a pipe on any speaker that I have made.
.

Sorry, I was referring to the more general concept of using those two drivers. Not the actual mounting/enclosures.

Thanks to your links I understand the benefits of a baffle.
 
.........Something like a simple 12mm ply board 9in tall 7in wide at bottom and 4in wide at top with 10F in middle will smooth all those ripples out. .............

Thanks XR, I cut baffles from scrap chipboard. The Scan Speaks were playing as I slipped the baffles on. I heard an immediate softening and fullness. I was not expecting any change from two small pieces of wood.
Hearing a change when not expecting a change means something changed.
Hearing a change when you are expecting, hoping to hear a change is a different matter.

[IMGDEAD]https://i455.photobucket.com/albums/qq271/tilroh/phono/ScanSpeak%2010F%208424%20w%20baffle%20XO%20-%201_zpshkxcrtah.jpg[/IMGDEAD]

and the proof is in the measurement:

[IMGDEAD]https://i455.photobucket.com/albums/qq271/tilroh/phono/end%20result_zpssvkf7a5j.png[/IMGDEAD]

Aside from booming bass, I can't tell much difference in between equalized and straight through. My friends and I have A-B-Ced $50 - $1k DACs and thought we might have heard a difference... maybe.
But no single thing has changed a system more than those two scraps of press-wood.

[IMGDEAD]https://i455.photobucket.com/albums/qq271/tilroh/phono/ScanSpeak%2010F%208424%20w%20baffle%20XO%20-%204_zpsjxfwjn9b.jpg[/IMGDEAD]


I'll do critical listening next week while ironing.

Thanks, Mack
 
But no single thing has changed a system more than those two scraps of press-wood.

:D

Nice work! Glad it cleaned up well. That's why I use a trapezoidal baffle for my Subjective Blind driver test threads - it adds the least cabinet based distortions to the response in a simple and effective way. Those are some pretty convincing measurements you have there. Nice. Thanks for trying it out! :cheers:

One more thing - if you are not opposed to kind of ugly finish of rough looking Scotchbrite Brillo pads on the baffle - add that I it will smooth the ripples by another 1.5 to 2dB in the critical 600Hz to 5kHz range and will sound even smoother. Ugly though. :). Maybe paint the Brillo pads black to match a black baffle and won't be as noticeable.

486387d1433306561-10f-8424-rs225-8-fast-ref-monitor-tg9fd-dagger-fast-passive-xo.jpg
 
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Eldam

Banned
2012-09-13 12:25 am
France
Hi,

What is please the efficienty of the 10F/8 at 1 m in this resistive load ?

Did you think at the cost of less dB to use the 10F/8 like Mister Linkwitz does with it LX Mini ? same as yours but thi time in OB with a thinner tube which just hold the magnet. It makes it more and more cardioid when the frequency climbs if I undestood the concept. You can choose a XO between 550/700. (look at the pictures here : https://www.madisoundspeakerstore.com/2-way-speaker-kits/lxmini-linkwitz-lab-speaker-kit-pair/)

But in the original design you need the woofer to radiate towards the ceilling : putted on the top of the cabinet.

But as you have active XO you could try first the concept with the 10F in open back conf. You could also add some a little boost to the 10F but this time by choosinf a higher XO to let the distorsion low; for instance 1000 Hz if the Dayton is able to climb as high !

Here a little reading about OB with and without bafle in relation to the targett you want to acheive (from Rudolf Finke : last download button) : Dipolplus - Alles über offene Schallwände

xrq971 at the opposite made also a nice horn in foam if you need a lot of efficienty with a XO as low as 500 Hz.

just my two cents

PS : @ x : Hi x, does your bafle with the Vifa had a little dB and lows the XO ? Or is it just here to move the frequency first dipole peak ?
 
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Eldam

Banned
2012-09-13 12:25 am
France
you mean from the edges of the driver basket or:in relation to a cabinet one ? Did you try like Linkwitz , i.e. free of front bafle ? (à la LX mini)

With your tatricx horn with open back conf for the driver, I'm asking if the OB attenuation could be the - 5 Db or in fact less due to the length of the horn between front & back emmitters ??? Did you remember if you liked more the SS 10F/8 with or without your less 1 liter back chamber please ?
 
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