Sound comparison between the “Simple Reflex” for Alpair 10.3/10p and the “Classic Golden Ratio Mar-Ken” for Alpair 10.3/10p

[planet10]

A10p is more “romantic” and has a “vintage” top-end.

The A10PeN outsold the A10.3eN 3 to 1, and was a favorite of the small high output impedance amplifier fans.

As the Silver A10.3 was much more popular in the UK & Europe, Copper in North America.

dave

 

[GM]

“Simple Reflex” historically is about a max flat alignment once all of the signal chain is taken into consideration; FWIW, my first 'read' on the subject: Critical Damping: The Missing Link in Speaker Operation

Over time, several folks took all the pioneer's knowledge and derived a ~ equivalent version for just a single driver alignment, extending it above and below Fs based on its acceleration bandwidth (BW), ending at the driver's upper (Fhm) and lower (Flm) mass corners and after all the 'dust had settled', Messrs Thiele, Small won out, hence T/S specs.

upper: Fhm = 2*Fs/Qts'

lower: Flc = Fs*Qts'/2 (AFAIK only useful for reactance annulled BLHs)

Qts': 2*Fs/Fhm

By 1981 it had boiled down to this:

In 1981 the Margolis/Small design routine became increasingly popular due to it being written for an early HP handheld calculator where ~0.403 Qts' combined with the box volume [Vb] = driver compliance [Vas] and box tuning [Fb] = driver resonance [Fs], i.e. T/S max flat BR alignment, so the pioneer's ideal alignment became the cornerstone of where traditional bass reflex [BR] ends and contemporary [under-damped] speaker box design begins.

Margolis-Small's HP 67/97 & 41C calculator program if wanting all the math for vented, sealed: http://www.aes.org/e-lib/browse.cfm?elib=3902

Vented net volume (Vb) (L) = 20*Vas*Qts'^3.3 (Ft^3 = (Vb)/~28.31685)

Vented box tuning (Fb) (Hz) = 0.42*Fs*Qts'^-0.96

F3 (Hz) = Fs*0.28*Qts^-1.4

(Qts'): (Qts) + any added series resistance (Rs): http://www.mh-audio.nl/Calculators/newqts.html

 

[norman bates]

I'm thinking dampening the schmoo out of it.

At 7:30 shows box tall pipe peak @ 175hz or so.
At 10:46, after dampening the enclosure, peak is basically gone.

 

[classAfreak]

Sort of. Despite the desperate marketing attempts in some quarters to elevate it to some separate profundity, impulse response is directly linked to FR (and CSD for that matter -you can generate both from an impulse response). The regular vented box I did has a flatter anechoic FR, that's all; it needs the extra Vb to provide that, & will be better sited away from room boundaries as a result. Just different alignments for different requirements, that's all.

Hello Scott,

many thanks to this interesting information.

Regards and a nice Weekend

Stefan

 

[fin.der6]

Hey Stefan, Did you make a cabinet in the end? I have some 10p's sitting about and was also trying to decide between an onken/marken or the simple reflex... tempted by the marken if it has better LF performance.

 

[GM]

Define 'better' since for some it's about how much gain BW while others are more interested in transient response, etc., so best of both is make it T/S max flat and damp to 'taste', with heavier damping to mimic the Onken's high resistance, ~aperiodic vents.

 

[planet10]

The basic reflex will likely give more bass, and a bit lower, the Mar-Kens have a more refined, elegant bass. The full-on trapezoid does give a lower diffraction signiture which makes for a greater sense of the box disappearing.

Quantity vrs quality.

Both are good.

dave

 

[GM]

Yeah, being lazy, always short of time I just cut kerfs on the baffle back side at driver frame or horn width and bent it backwards at a 1:12 slope and called it 'good enough' for 'slap echo', good enough for a speaker, though never measured one nor had/have any software to sim it AFAIK, though one pro cinema/HT designer said I needed to double it vs my assumed summed baffle slope met the 2:12 required.