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-   -   Alpair 6p vs alpair 6m vs alpair 7 (http://www.diyaudio.com/forums/markaudio/186193-alpair-6p-vs-alpair-6m-vs-alpair-7-a.html)

timreeves 31st March 2011 11:08 PM

Alpair 6p vs alpair 6m vs alpair 7
 
Ok
So I'm looking at building some speakers using one of these drivers in an OB arrangement with a sealed peerless 830669 taking over for bass duties. Crossed somewhere between 100Hz and 300Hz (I listen to a lot of house, dubstep, rock and metal)

The most important factors for me are impact and imaging, you guys seem to be pretty familiar with these drivers and I'd love to hear any suggestions or input you may have regarding my choices.

planet10 1st April 2011 03:22 AM

Biamp? If you use the 7 (which i have heard) you could XO as low as 150-200 Hz), the A6 (on the break-in bench, i haven't heard) would have to be XOed higher to maintain the impact.

dave

timreeves 1st April 2011 05:34 AM

I didn't want to bi-amp no, I'm a passive purist at heart.
I don't suppose you would have any input as to what sot of XO point imaging starts to deteriate noticeably on the 7?

planet10 1st April 2011 07:35 AM

If you go passive, you will have to consider efficiency in the equation. And given component size for a passive you probably don' want to cross <200. Given impedance peaks 300-400 looks nice.

This Peerless? Alpair 6P is likely to be best match with a passive XO.

What kind of amp do you have?

dave

timreeves 1st April 2011 05:46 PM

That's the sub, yep.

They'll start life on a technics SU-V4 but after these have been built I'm going to build one of the kits off classdaudio.com

I was hoping the 6p would be recommended out of the 3, I've always had a soft spot for paper cones. I have the ability to do an active crossover for these guys first, so will probably have a little play bore deciding on a suitable passive point somewhere between 200 and 500 looks do-able going by the impedance curves

planet10 1st April 2011 07:14 PM

I had really good luck XOing the FF85 to a pair of MA #6 woofers. 4 ohm bottom & 8 ohm top gave me a situation where i could use a "small" cap & "small" inductor (series XO worked out best). With the opposite situation you have values will be doubled vrs mine (to a 1st approximation, you'd need 60uF, 6mH.

dave

chrisb 1st April 2011 07:54 PM

Quote:

Originally Posted by timreeves (Post 2523749)
I didn't want to bi-amp no, I'm a passive purist at heart.


I'm curious if there's any particular reason for that? In the few multiway systems that I've built in the past 10yrs, I've generally preferred the clarity and flexibility of PLLXO and active bi-amping.

Of course you could always go passive in a bi-amped system and with input volume controls at least eliminate the need for attenuation, but personally I'd consider that a half measure.

If it's a matter of contour /FR shaping, that's readily attainable with EQ software in computer based music systems these days, or gadgets such as the Behringers*, but driver impedance compensation via Zobels would still need to be accomplished at speaker levels.

* of course by many accounts the sonics of these in stock form leave substantial room for improvement, so it could well be that with sufficient amplifier torque on hand, a few hundred dollars worth of quality passive components would still cost less and yield better results

so I'll just crawl back in my little FR corner

timreeves 1st April 2011 08:55 PM

I will definitely be giving series crossover design a go once i've got the drivers and setup all my test gear again, would love to get something as minimalistic as possible.

Which brings me onto why I'm a passive purist. Speaker design to me is about creating something that is viable in the commercial world, something that just plugs into an amp and away it goes. It's also about the art of sound jsut as much as it is about getting a flat frequency response. I plan on keeping the crossovers at costing no more than $100, over that on a 2-way system to me is either a serious case of bad driver matching or an equally serious case of diminishing returns.

Which brings me onto probably my main sticking point... The amount people live by zaph's graphs and recomendations, a photo can still be beautiful if the colours are out or it's not all in focus - yet if someone told you about a photo that was off-colour and out of focus it would be very easy to dismiss it straight away. I see it the same with speakers, ok there may be some harmonic distortion - but does it make for a worse sounding speaker?

planet10 1st April 2011 09:29 PM

Quote:

Originally Posted by timreeves (Post 2524549)
... The amount people live by zaph's graphs and recomendations...

Seems to me, that you & i may share much the same opinion of Zaph's work.

dave

_henry_ 25th April 2011 09:05 PM

i think bi-amping with dsp active xo, can help u alot on designing the passives.

it is almost impossible to get the correct crossing and shaping without active xo and measurements. Well except for few nice drivers like alpairs (which i felt no need for shaping at all) even the 5 which have peak around 13-14khz.

cheers
henry


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