Silver Flute W20 in Dynaco A25 Enclosure?

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Hi there, just kicking an idea about and am curious about something. Say one takes an old Dynaco cabinet from some A25's (.85cf IIRC), and replaces the 10" woofer with an 8" Silver Flute woofer... would this work?

The recommended enclosure for the W20 is 0.8cf with porting, would an aperiodic enclosure work with such a driver? If so, is the Dynaco cab a suitable place to start experimenting?

Any advice would be appreciated. Just kicking some ideas about.
No, an aperiodic enclosure is nothing more than a pressure relief vent, it's not a tuned port, and that driver has a low Qts that really needs a well implemented ported box design to get the most out of it. On top of the tuning issues, you would need to re-do the front baffle to accommodate the smaller driver diameter which would be difficult to do without hacking the box. Another possible issue could be the box depth might not be enough to allow a straight port tube, it may be necessary to use a port with a elbow to keep the internal end of the port away from the cabinet walls.
IMHO, if you are set on using that driver, I'd start with a clean slate and either build a box from scratch or find a pre-made box that is better suited.

I can't imagine how you are going to fit an 8" woofer in a cutout for a 10" really.

The Silver Flute is wildly different from the old Dynaco woofer anyway.

The A25 used a woofer with a natural rolloff around 2kHz and a higher Qts around 0.4, having very high inductance, which is like a bafflestep coil built in:
SEAS A26 Kit

0.8 cu feet might suit a lot of 8 or 10" woofers, so something might be doable, but you will probably need to add a reflex tube, as mentioned. You'll also need a crossover circuit more sophisticated than the A25 style.
I figured it wouldn't work, but appreciate the feedback. The why is where one like myself learns, so appreciate the explanations.

They are throwaway enclosures, I would be making another baffle for them, but it seems that the W20 wouldnt work in an aperiodic enclosure huh? I thought of porting them as well, but think the enclosure is too shallow.

Lacking the ability to make a quality enclosure with just a router and limited tools, but a baffle is no issue for me as I have played with OB speakers for some time. Was looking at trying a more traditional approach to something. Thanks all.
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I'd put W20 into 14 litres (F10 50-), the dyna cabinet is 24 litres. A real droopy alignment could be done, a 1st approx, tuned to 43 Hz (F10 mid30s).


The quality of the A25 cab is marginal… unless you can't start from scratch.

Dynaco speakers were purpose designed to complement (compensate for :) Dyna Amps; farty Bass and sketchy Highs.
They did their job quite well, truth be told.
Not such a great matchup with more 'capable' moderne upstream gear though.

Shouldn't be a surprise.. given that it's NO Longer 1973 !!
If you are fitting a new baffle to 24L (0.8cu foot?) Dynaco A25 boxes, I'd think you could get quite good results with any old 8" bass and a port.

Bass response is hardly an exact science when you add room gain and placement factors. I used to do all sort of naive stuff like get adjustable ports and put drinking straws in them. I was naive enough to enjoy the result. :D

You're probably at the low end of what Eminence recommend for the Alpha 10, but an Alpha or Beta 8 would probably work well-enough too.
Speaker Detail | Eminence Speaker
I did this Alpha 8/Audax TW034 idea with a second order filter (2mH/10uF bass, 3.3uF/0.3mH tweeter and some fiddling with resistors for level) some years back in a 0.8cu foot Wharfedale Linton box, and it was very good. And LOUD. Tekton still make likeable speakers like this.

In the Pispeakers 2Pi Wayne Parham pairs this Alpha 10 with a loud 104mm Tymphany DX25TG59-04 1" Fabric Dome Tweeter: Tymphany DX25TG59-04 1" Fabric Dome Tweeter

Simple 0.5mH bass coil, 10uF and 16R shunt. Cheap entertainment. Probably work with the Dynaco Aperiodic port. What you need to know is that aperiodic or damped port is about halfway between Qts 0.38 reflex and Qts 0.5 closed box. Have a go. :cool:


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Would a 10" Eminence work in an A25 cabinet as a midbass speaker in an active 3 way system? I have a pair from an old bass cabinet that spec as such:
05-RE OHMS 7.14 13-FS HZ 52.69
06-LE MH 1.11 14-MMS GMS 28.00
07-QM 6.20 15-CMS mm/N .3255
08-QE .430 16-RMS NS/M 1.4974
09-QT .410 17-VAS LTRS 54.38
10-XMAX MM 2.40 18-SD SCM 344.88
11-BL TM 12.35 19-EBP 121.4
12-EFF % 1.77 20-SPL dB 94.5
What you need to know is that aperiodic or damped port is about
halfway between Qts 0.38 reflex and Qts 0.5 closed box. Have a go. :cool:


No. Its nowhere near either of them. Where did you get that idea ?

An aperiodic damped port does not phase invert like normal ports,
and represents a leak of cancelling output compared to a closed
box, and is only useful for drivers that are boomy in a sealed box.

It reduces the peak, but is very difficult to get right. Too low damping
its just a vented boom box, too high it is barely different from sealed.

Something IMO that cannot be designed on paper, needs measurements.

Personally I find the series capacitor route for boomy sealed boxes
far more useful and predictable, reliable and practical. Hence the
rise of the latter and the demise of the former commercially.

rgds, sreten. Homemade Hifi_Black Box.pdf

The free version of Basta! is good for modelling series capacitance.
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