I'm looking to build an Alpair 10.3 FAST floorstander pair and need some guidance.
Original plan was to build Pensils but I realized that my placement close to wall & corner may be problematic for lower end.
So I built simple sealed boxes for the Alpair and they already go down to almost 30hz, especially the corner side. To be able to adjust the lower end the plan is to build separate sub parts, to replace the 1 sub I already have.
Size would be around 900x210x330mm for sub parts, 18mm plywood, 40l with tuning around 29hz resulting in F6 around 25hz. Woofer on the side with vent facing back.
Amp Monacor 300d, woofer GZIW 250X
Top part sealed for 10.3 would be around 210x210x330mm with 18mm plywood, around 7l with F6 around 80hz.
Questions:
Any major issues that I'm missing?
What is a good crossover range, around 100-200hz? I will use active crossover from plate amp/main amp
How should I place the woofers, facing outside or inside, or even same direction?
How should I connect them, subs in RCA mono from main amp or speaker level per side to both top&bottom parts?
I have a measuring kit coming so I can do basic measuring if needed. Main amp is Denon x1400 so I can use it for some EQ for the subs.
Original plan was to build Pensils but I realized that my placement close to wall & corner may be problematic for lower end.
So I built simple sealed boxes for the Alpair and they already go down to almost 30hz, especially the corner side. To be able to adjust the lower end the plan is to build separate sub parts, to replace the 1 sub I already have.
Size would be around 900x210x330mm for sub parts, 18mm plywood, 40l with tuning around 29hz resulting in F6 around 25hz. Woofer on the side with vent facing back.
Amp Monacor 300d, woofer GZIW 250X
Top part sealed for 10.3 would be around 210x210x330mm with 18mm plywood, around 7l with F6 around 80hz.
Questions:
Any major issues that I'm missing?
What is a good crossover range, around 100-200hz? I will use active crossover from plate amp/main amp
How should I place the woofers, facing outside or inside, or even same direction?
How should I connect them, subs in RCA mono from main amp or speaker level per side to both top&bottom parts?
I have a measuring kit coming so I can do basic measuring if needed. Main amp is Denon x1400 so I can use it for some EQ for the subs.
Last edited:
Now i’ll put my badge away.
My sim suggests that 6 litres or a bit less for a damped sealed box with max flat alignment. But anywhere up to about 15 litres would be fine.
How high you cross depends on a number of things. Yesterday i summarized many of the things you should consider when placing the XO: FAST (WAW) build help and opinions (Post #18). You’ll probably find other relavant info.
But…
I am not familiar with the plate amp you mention, but most do not have a real hi-pass function. That makes them best used in what i call a REL configuration. Run the FR sans any filters, just using the 2nd order roll-off of the box. And then bring the sub in elow that. For a ~6L box that is going to be about 85 Hz. That low you have the option of running the woofers in mono. I like to run them stereo but your room will likely let you know which is best. 2nd order on the woofer HP would be symmetrical, but they often come 4th order. Again room, and how hifh doe sthe woofer go.
dave
My sim suggests that 6 litres or a bit less for a damped sealed box with max flat alignment. But anywhere up to about 15 litres would be fine.
How high you cross depends on a number of things. Yesterday i summarized many of the things you should consider when placing the XO: FAST (WAW) build help and opinions (Post #18). You’ll probably find other relavant info.
But…
I am not familiar with the plate amp you mention, but most do not have a real hi-pass function. That makes them best used in what i call a REL configuration. Run the FR sans any filters, just using the 2nd order roll-off of the box. And then bring the sub in elow that. For a ~6L box that is going to be about 85 Hz. That low you have the option of running the woofers in mono. I like to run them stereo but your room will likely let you know which is best. 2nd order on the woofer HP would be symmetrical, but they often come 4th order. Again room, and how hifh doe sthe woofer go.
dave
Attachments
Many thanks Dave, for both the help with the post and guidance. I've been lurking around for a while and finally had the courage to start my own build.
Running the subs in mono would be easiest, I can then later add MiniDSP in the mix if needed.
Any tips on the woofer alignment, is there any issues having them face each other? That would be easiest as then they would be protected from the little ones.
Running the subs in mono would be easiest, I can then later add MiniDSP in the mix if needed.
Any tips on the woofer alignment, is there any issues having them face each other? That would be easiest as then they would be protected from the little ones.
As long as you put one in the opposite phase, there is none. But if you wire them both in phase and then put them facing each other, they will cancel out as they are 180° out of phase. The easiest way to do that phase switch is to switch the + and - signal cable at the driver connectors. Connect the + to the - connector of the speaker and the - to the + connector.
Thank you, I didn't realise that I can use the phase adjustment. I have phase adjustable in both subs from the plate amp, another good thing about active subs.
I’d still suggest that high passing the sealed Alpairs - whether by simple PLLXO or more flexible active XO methods - would yield benefits well worth the effort.
Dave and I have cumulatively played with quite a few brands and models of plate amps over the years, and while they do offer lots of convenience, I tended to avoid them for at least the last 5yrs of my active building. Very few units had decent HP functions - most none at all- and the lower priced 2.1 units were, to be polite, not quite up to our standards. Rhymes with trucking sad.
We had several builds with side mounted woofers; singles and multiples, mono- and bi-pole, and I can’t recall ever having issues with bass performance in Dave’s fairly spacious room that is very accommodating in that regard. Smaller rooms with asymmetrical boundary loading might be more problematic - your picture does show very tight on the right side.
At one time I had systems in three separate rooms - one was a long and skinny basement room that hardly improved much with rather a lot of DIY acoustic treatment, and I gave up on any more elaborate that near field computer micro sized boxes with a 3” FR driver. The large two rooms are approx 320sq ft and well over 600 if you account for the open floor plan. But for some of us furniture and WAF get in the way of what could compose an ideal system, and after over 30yrs of my wife putting up with some pretty awkward arrangements, it occurred to me that domestic peace in my impending and now present retirement years was far more valuable than any short term enjoyment .
Tranquility > ecstasy? Maybe- certainly more effortless for me to maintain.
So, you might want to consider the option of larger enclosures for the Alpairs to retain their LF extension capabilities, but still HP them - say circa 100-120- and implement mono bass, with multiple boxes located around the room. IINM, that’s something that minidsp and plug-in solutions can readily handle.
Of course, I’ve been a big fan of simple floor standers that meld into the room’s furnishings over chunky and visible multiple boxes for quite some time now (see above) . Small sealed woofers can be a lot easier to hide - or you could go the coffee table / cocktail shaker route.
Dave and I have cumulatively played with quite a few brands and models of plate amps over the years, and while they do offer lots of convenience, I tended to avoid them for at least the last 5yrs of my active building. Very few units had decent HP functions - most none at all- and the lower priced 2.1 units were, to be polite, not quite up to our standards. Rhymes with trucking sad.
We had several builds with side mounted woofers; singles and multiples, mono- and bi-pole, and I can’t recall ever having issues with bass performance in Dave’s fairly spacious room that is very accommodating in that regard. Smaller rooms with asymmetrical boundary loading might be more problematic - your picture does show very tight on the right side.
At one time I had systems in three separate rooms - one was a long and skinny basement room that hardly improved much with rather a lot of DIY acoustic treatment, and I gave up on any more elaborate that near field computer micro sized boxes with a 3” FR driver. The large two rooms are approx 320sq ft and well over 600 if you account for the open floor plan. But for some of us furniture and WAF get in the way of what could compose an ideal system, and after over 30yrs of my wife putting up with some pretty awkward arrangements, it occurred to me that domestic peace in my impending and now present retirement years was far more valuable than any short term enjoyment .
Tranquility > ecstasy? Maybe- certainly more effortless for me to maintain.
So, you might want to consider the option of larger enclosures for the Alpairs to retain their LF extension capabilities, but still HP them - say circa 100-120- and implement mono bass, with multiple boxes located around the room. IINM, that’s something that minidsp and plug-in solutions can readily handle.
Of course, I’ve been a big fan of simple floor standers that meld into the room’s furnishings over chunky and visible multiple boxes for quite some time now (see above) . Small sealed woofers can be a lot easier to hide - or you could go the coffee table / cocktail shaker route.
I am not familair with that woofer so can’t speak to alignment, but do keep room gain in mind and don’t try to push them too low.
At the frequencies involved it is unlikely important where you put the woofer. I do like using 2 x a size smaller woofer and taking advantage of the huge gains one gets with push-push reactin force cancelation.
dave
Waxx’s response makes me question my interpretation. Does this mean 2 woofers in 2 boxes with the woofers oriented to face each other or as Waxx seems to imply, are they being used in an isobarik configuration?
dave
We did get one of those. It truly sucked. Daniel had a look at it and removed a compressor board out of the circuit and it became quite reasonable. I use it with a sealed SDX7 and have some sealed A10.2s as satelites.
dave
Thanks, it's just one woofer per box, no isobarik setups yet.
I'll place them facing inside, keeps the little ones away from poking holes in them.
I’d still suggest that high passing the sealed Alpairs - whether by simple PLLXO or more flexible active XO methods - would yield benefits well worth the effort.
Dave and I have cumulatively played with quite a few brands and models of plate amps over the years, and while they do offer lots of convenience, I tended to avoid them for at least the last 5yrs of my active building. Very few units had decent HP functions - most none at all- and the lower priced 2.1 units were, to be polite, not quite up to our standards. Rhymes with trucking sad.
We had several builds with side mounted woofers; singles and multiples, mono- and bi-pole, and I can’t recall ever having issues with bass performance in Dave’s fairly spacious room that is very accommodating in that regard. Smaller rooms with asymmetrical boundary loading might be more problematic - your picture does show very tight on the right side.
At one time I had systems in three separate rooms - one was a long and skinny basement room that hardly improved much with rather a lot of DIY acoustic treatment, and I gave up on any more elaborate that near field computer micro sized boxes with a 3” FR driver. The large two rooms are approx 320sq ft and well over 600 if you account for the open floor plan. But for some of us furniture and WAF get in the way of what could compose an ideal system, and after over 30yrs of my wife putting up with some pretty awkward arrangements, it occurred to me that domestic peace in my impending and now present retirement years was far more valuable than any short term enjoyment .
Tranquility > ecstasy? Maybe- certainly more effortless for me to maintain.
So, you might want to consider the option of larger enclosures for the Alpairs to retain their LF extension capabilities, but still HP them - say circa 100-120- and implement mono bass, with multiple boxes located around the room. IINM, that’s something that minidsp and plug-in solutions can readily handle.
Of course, I’ve been a big fan of simple floor standers that meld into the room’s furnishings over chunky and visible multiple boxes for quite some time now (see above) . Small sealed woofers can be a lot easier to hide - or you could go the coffee table / cocktail shaker route.
Thank you Chris!
Yep, I have some WAF acceptance issues although she is quite flexible in the short-term with various cables, boxes and things lying around. In the current setup I actually have 1 subwoofer placed under the sofa, it was the only place available due to above issues but I'm not perfectly happy with how it performs.
I want to have floorstanders but with adjustable lower end so this was the best compromise I could think of, separate subs would be great but so far it's out of reach. The current Elac FS137 floorstanders actually go down to 30hz with room gain but it results in massive 10db drops/spikes between 30-100hz so I'm hoping that the small sealed boxes won't peak so badly and with 2 subs I can compensate & EQ them better. Audyssey seems to EQ subs better than main speakers and MiniDSP is on the shopping list for the future.
I'll keep the HP filter part in mind, I just received my measuring kit (ECM8000 mic with stand and USB soundcard) so I'll be able to test and add a crossover if it feels like it's needed.
I managed to measure my current prototype sealed boxes and I'm quite happy with how it's looking.
This is from the main listening position per channel and then both channels with the current under the sofa sub in action.
Left side is opening into a large space and it shows, right side is getting a great boost from corner placement which results in quite a nice smooth response?
May need to bring down the high end >8khz a little?
Looks like the Alpairs are pretty smooth down to 30hz so definitely no additional low end stretch needed from larger enclosures. I'm hoping that my stereo subs will help sort out that big valley between 80-150hz, I'll need to experiment with different crossover points and sub levels.
Any other opinions?
This is from the main listening position per channel and then both channels with the current under the sofa sub in action.
Left side is opening into a large space and it shows, right side is getting a great boost from corner placement which results in quite a nice smooth response?
May need to bring down the high end >8khz a little?
Looks like the Alpairs are pretty smooth down to 30hz so definitely no additional low end stretch needed from larger enclosures. I'm hoping that my stereo subs will help sort out that big valley between 80-150hz, I'll need to experiment with different crossover points and sub levels.
Any other opinions?
Attachments
Building started, still some bracing to be added and I'm missing a router but so far so good. All parts are ready, will assemble when I find the router.
Really easy to build from 18mm birch ply and Titebond, earlier prototypes from 12mm were much trickier plus Titebond is the best glue I've ever tried!
Really easy to build from 18mm birch ply and Titebond, earlier prototypes from 12mm were much trickier plus Titebond is the best glue I've ever tried!
Attachments
Titebond 3 I hope!
If you need a cheapy router, check out the Katsu ones on Amazon. Makita clones, can't do much heavy lifting, but good for baffles.
I have some CNC jigs made for routing the rebate and internal cut-out (irregular shaped) if your interested, but they are only for the newer drivers pluvia7/7ms & pluvia 11/11ms. Idea was to sell them.
If you need a cheapy router, check out the Katsu ones on Amazon. Makita clones, can't do much heavy lifting, but good for baffles.
I have some CNC jigs made for routing the rebate and internal cut-out (irregular shaped) if your interested, but they are only for the newer drivers pluvia7/7ms & pluvia 11/11ms. Idea was to sell them.
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