Mark Audio Alpair 6P Application Thread

[simon dart]

This is my first real venture into full range, reasoning tiddly drivers can't do real bass, I got a pair of Alpair 6P with a view to FAST-ing them eventually.

Whilst running them in I temporarily mounting them in boxes I had lying around and in a big open baffle. I learned that they are very sensitive to obstruction around the rear of the basket. Placing one driver over another playing music showed the ultra light cones are very acoustically transparent as you'd expect if you stop to think about it. So I decided to use a scrap piece of 5mm aluminum as the baffle to present the minimum obstruction to the rear of the cone.

So to get a feel for the drivers I thought I'd do a simple Bass Reflex to get them broken in and get familiar with them. Win SD gave me 4.4litres tuned to 69Hz. I thought I'd try a slot port, 100mm wide, 12mm high by 105mm deep. I fixed the port length but left the width defined by some little fillets so I could tune the port width, and so the frequency, afterwards. As it happens tuning was spot on using the calculator

PORT Size Calculations and Formulas for WOOFER and Subwoofer BOXES

Perched on top of a heatsink close to a wall on my desk they are sounding very musical in the near field on the end of a modded Quad 306 driven by my PC DAC and a Quad 44 FM tuner.

I'm greedy, I want everything from a speaker but old enough to realise you can't have it! The bass is surprisingly tuneful and robust, lower treble has some paper "character" but there again I wouldn't expect it to resolve like an AMT. The mids are incredibly transparent. Planet 10's expresion of "downward dynamic range" being a MA characteristic is right on the money. You can hear very deep into a recording, much like headphones. They have a sort of irrepressible character, very engaging.

Time to try them on my main system!

[planet10]

I'm currently playing with an early prototype of the A6p in a millSize box (4.7 l) in preparation for the production A6p to come off the breal in bench.

Keep us apprised of the progress these make as they break in.

dave

[simon dart]

I hooked them up to my CDPro-AYA player and EL34 push pull triode strapped amplifier this afternoon. They sound so big! No problem with my 10m x 6m room. OK no extreme bass, but much like an LS3/5a, well proportioned. Mark's built in BSC works a treat. Huge walk in soundstage, all the benefits of no crossover and teeny moving mass providing lots of resolution. I wasn't expecting such a complete performance from a 3" driver even given the "shiny new toy factor". Just have to see if the HF improves with hours, thats my only beef.

I can see myself spending a bit more time in full range land. Now anyone got some bright ideas about alternative enclosures?

[StevenZ]

Sub'd. Very interested.

[andb]

Hi Simon, how have things been going with the 6P's? How are they now that they are broken in? Did you manage to mate them to a sub yet?

[simon dart]

They sit either side of my monitor and play 8hours a day five days a week so I guess even Mark Fenlon would say they are broken in now! It may be that I have got used to their tonal signature, as we do, or they have got a bit smoother with time. The slightly "paper" character doesn't bother me half as much as it did when they were fresh, I barely notice it most of the time. Although they aren't as clean in the HF as a really good tweeter as you'd expect, the openness through the presence region you get from no crossover, together with great micro dynamics, is magic.

I don't really know how they stack up against other full rangers of similar diameter, but for a near-field application I'm really enjoying them. They are wonderfully expressive and detailed.

I haven't played around with FAST-ing them yet. They have suprisingly good bass, so its not been the urgent task I expected in my desktop application. I really want to try PC- DSP - 4x DAC-active, which looks like it may be within reach really soon with devices like ExaU2I coming to market. I can feel mating them to mid-fi bass is going to be selling them short.