helper subwoofer for Alpair 7.3 or new FAST /WAW build?

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In the last years i used with great success a pair of Alpair 7.3 in vented boxes as a nearfield setup for my desk, picture attached (ignore the unfinished look, it didn't bothered me enough to finish them)

I'd like to add some low end to the system but it needs to be at the same sound quality as the speakers (i don't need the sub to go very low or very loud i just want great integration).
Is an active sealed small sub(around 8") a good ideea for them or a new small FAST build could be better (i was thinking something similar to the Boenicke W5 as i would like to keep them on the stands)

I must add that my understanding of technical stuff regarding speaker building is limited, i like to have a premade plans (like the ones from planet 10 i used for the alpairs)


8SZBPXh.jpg
 
frugal-phile™
Joined 2001
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There is a very large number of suitable bass drivers. Much smaller if you prefer to build a sealed woofer. You want to look for a midwoofer that is typically used to crossover to a tweeter, something that reaches up to a minimum of 1kHz.

We have used Alpair 12pw, SilverFlute W14, Peerless 830870, and EL166 in ML-TLs (you can still getthe 1st 3), and SDX7 in sealed box (the new CSS are talking about bringing it back). The largest of these are 7”, the smallest 4”. The smaller drivers reach 35 Hz F10, the larger drivers lower.

I also have designs for miniOnken alignment for the SF W14. And i have done a couple designs for some Scan-speak drivers (i’d have to look uo what they are).

I have looked at a couple 10” SB Acoustics that work in sealed boxes.

What you want to do is look at easily available woofers in the size and price you can budget, then model the response until you find something suitable. You want to look at a Q between 0.5 & 0.707, sealed box size id not overly critical but as you go lower Q the box size goes up exponentially. I typically target 0.58. Remember that damping in the box can increase the apparent box size by as much as ~20%. Shape is not overly critical as long as one dimension does not get a lot bigger than any other (then it starts to behave like a half-wave TL.

Get back with some of the available woofers and we can confirm your findings … i am always on the look out for suitable woofers.

dave
 
I built a FAST/WSW with a Dayton RS-225 and a Fostex FE85. I'm extremely happy with it. I've given a lot of consideration to the Mark Audio Alpair 12 and Alpair 5 combination. That said, I have a pair of Alpair 7.3 Frugalhorns which do an outstanding job. Needless to say, I rotate my speakers occasionally.
Mike
 
You want to look for a midwoofer that is typically used to crossover to a tweeter, something that reaches up to a minimum of 1kHz.

Hi Dave, you recommend a woofer that reaches up to 1khz for the FAST option, right?

At this moment i'm leaning more and more to a separate subwoofer option, i was thinking that a FAST build with a high crossover point would lose some of the nearfield qualities (they would need more space/distance from listening point to sound best?) - might be wrong..

On the other hand, a separate sealed subwoofer with a crossover around 100-120hz would allow me to keep the actual setup (speakers on stands at around 4 feet equilateral triangle) and retain most of the frequency range of the alpairs(which i like v much) + easier to build. Should i open a new thread on the subwoofer section maybe?

As i said in the first post, my speaker design knowledge is limited and i might be missing an obvious point without realizing.
 
frugal-phile™
Joined 2001
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If the A7.3 are used near field, and the box they are in already goes low enuff then yes that will work.

You still need a woofer with an extended range… typical subwoofers (aka atmosphere generators) won’t mesh well with the FR. Since it doesn’t need to go real low i’d still be using the same criteria to choosing it… i have a couple small SDX7 stand alone ‘subs’ that would fill that role well — you would do well to emulate something like them). Same procedure for finding the woofer.

It sounds like your situation is such that you could follow the “REL” method to add the woofer. Don’t use a hipass on your A7 and dial in the woofer to blend with them (use a plate amp with an XO in it).

dave
 
If the A7.3 are used near field, and the box they are in already goes low enuff then yes that will work.

The enclosures are your own design, the dMark-Ken 7.3 (if i remember well you said i was the first client for the plans from Romania back in 2013) - and the bass performance is very good for the size - hence the no upgrade plans in the last 4 years.

I will browse the available european crop of woofers with the specs recommended and i will return with some findings
 
frugal-phile™
Joined 2001
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I thot they looked familiar. With the light as it is, i didn’t make out the vents — they are clear with a little gamma adjustment :)

You’d want to bring a woofer in to start at about 50-55 Hz, and then adjust from there if you want to do the REL method. You are wide open if you want to add a hi-pass.

As always trust your ears… with no low bass you should not hear the woofer.

dave

dave
 
Very similar to the plans I'm working on myself. I will be running 2 subwoofers (Seas L26ROY with passive radiators). The sub boxes will be acting as stands for either Alpair 7.3 or the Jordan Eikona 2 in sealed cabinets above... Drivers will be crossed at 120hz. I can't decide between the Alpairs or Jordans though. Ive used Alpair 6P, Alpair 7.2, Alpair 7.3 and Alpair 10P in many different configurations and have never been disappointed, but giving the Eikonas a try would be a lot of fun, even with the high price tag...
What do you guys think?
 
frugal-phile™
Joined 2001
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Ive used Alpair 6P, Alpair 7.2, Alpair 7.3 and Alpair 10P in many different configurations and have never been disappointed, but giving the Eikonas a try would be a lot of fun, even with the high price tag...
What do you guys think?

A7.3eN is my current favourite… but i’ve gotten ahold of a pr of A7 MOAP, which i will EnABL sometime after experimenting on a reject cone from Mark. The MOAP is head-to-head with the EnABLed A7.3 — maybe a bit more neutral — so i expect good things.

I really want to try the Eikona, but they are too much $$$ at the moment and i’m a bit gunshy after finding the JX92s a disappointment.

dave
 
Ive used Alpair 6P, Alpair 7.2, Alpair 7.3 and Alpair 10P in many different configurations and have never been disappointed, but giving the Eikonas a try would be a lot of fun, even with the high price tag...
What do you guys think?

11opas,

If you were to try out the Eikona 2, then that would make you one of the very few who have actually heard the latest drivers from both camps. Look forward to updates. :)
 
scott - perhaps just my particular situation, but during the past 15yrs, I've probably only paid for a single pair of drivers - the MAOP7s, which are now part of Dave's own collection - so I've become used to trading my labour (sweat equity) for speakers.

My next spare grand or so of discretionary spending would certainly have a couple of pairs of these on a short list - the rumored Tesla Pick-up truck will just have to wait.
 
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