subwoofer augmentation for alpair 10.2

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i am hopping on a speaker project using alpair 10.2 drivers. i wil go with either erich haartmann's bookshelf design or simple pencil box. although 10.2 can go down pretty well, i would like to augment the lower bass with subwoofer to take out some stress from the alpairs. i am looking for suitable subwoofer in a sealed box(for tighter bass). pls suggest one which will pair well with the alpairs. i could go for biamping with active xo
 
Yes the H frame is dipole. "Tighter bass" might mean different things to different people but to me it would mean clean, clear, true to the live event, and free from enclosure colorations. Dipole pressurizes the room differently than sealed (yes I have both although my sealed is a servo). Sealed can have more of that "bang in the chest' impact but not necessarily more "real life". H frame likes to be a bit away from the wall so tucked tight into a corner might not work (don't really know never tried that). You might also consider how far the corner placement is from the main speakers. More than 8 feet can be problematic, however adjustable phase control on your sub amp (not just those 0-180 switches) can help. Common wisdom is that subs crossed over under 80Hz are difficult to locate viz a viz the main speakers. Uncommon wisdom would say 50Hz is more like it. If it was my $400 I'd just build 2 of the H frames and enjoy the music. No matter what you do in the future I bet those H frames will be with you forever.
 
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I'd be leary of mixing a dipole woofer with monopole top. I can also say that, having a pair of unused goldwood, i am not entralled with the build quality, its main asset is that it is big, And cheap. An H-frame will also have cavity resonance that means it is not as extended at the top as i like when integrating with a FR,

Yjru might be great, i have just not been inspired to try them. The Eminece 15" H-frames are built but haven't seen much use.

For a solid foundation on the bottom, i chose CSS SDX10, which i am running sealed.

dave
 
I have my H frames crossover at 70Hz with 24dB slope so no cavity resonance issues really. However now that you mentioned you want a single sub with a corner placement, and since Dave likes the SDX10 (haven't heard them but I'd trust Dave's opinion) why not look at one of the kits that CSS sells. If you can stretch the budget a bit, CSS offers the Antimode digital subwoofer equalizer at a nice discount with their kits and I can tell you those things work the kind of magic you'll really appreciate integrating a single corner placed sub with your Alpair 10.2's. I heard the Antimode in a set up with twin tower subs of 6 peerless 12 inchers and all the boom disappeared and the real deal was there big as life.
 
Yes the H frame is dipole. "Tighter bass" might mean different things to different people but to me it would mean clean, clear, true to the live event, and free from enclosure colorations. Dipole pressurizes the room differently than sealed (yes I have both although my sealed is a servo). Sealed can have more of that "bang in the chest' impact but not necessarily more "real life". H frame likes to be a bit away from the wall so tucked tight into a corner might not work (don't really know never tried that). You might also consider how far the corner placement is from the main speakers. More than 8 feet can be problematic, however adjustable phase control on your sub amp (not just those 0-180 switches) can help. Common wisdom is that subs crossed over under 80Hz are difficult to locate viz a viz the main speakers. Uncommon wisdom would say 50Hz is more like it. If it was my $400 I'd just build 2 of the H frames and enjoy the music. No matter what you do in the future I bet those H frames will be with you forever.
i came across one such speaker..Jim Griffin's open minded. its pretty tempting.
 
i am planning to go for 18" pro subwoofer in a sealed box. powered with sufficient power with enough headroom to reach target SPL of 90dB minimum(so may be 800W). have anyone tried integrating 18" or bigger sub with alpairs?

Hello Soundnovice,
Why do you need such a large sub woofer? Is your room unusually large? Or, are you in need of huge power for rock un roll music and similar? If so, then you'll have to accept a system with severe limitations for other forms of music, much of which has higher/wide degrees of acoustic definition. You may benefit from reading some of the more recent posts on this thread, especially post No 120:

http://www.diyaudio.com/forums/markaudio/224477-future-woofer-production-12.html

Cheers
Mark.
 
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I'd be leary of mixing a dipole woofer with monopole top. I can also say that, having a pair of unused goldwood, i am not entralled with the build quality, its main asset is that it is big, And cheap. An H-frame will also have cavity resonance that means it is not as extended at the top as i like when integrating with a FR,

Yjru might be great, i have just not been inspired to try them. The Eminece 15" H-frames are built but haven't seen much use.

For a solid foundation on the bottom, i chose CSS SDX10, which i am running sealed.

dave
Dave : Which enclosure are you using?
Don
 
Hello Soundnovice,
Why do you need such a large sub woofer? Is your room unusually large? Or, are you in need of huge power for rock un roll music and similar? If so, then you'll have to accept a system with severe limitations for other forms of music, much of which has higher/wide degrees of acoustic definition. You may benefit from reading some of the more recent posts on this thread, especially post No 120:

http://www.diyaudio.com/forums/markaudio/224477-future-woofer-production-12.html

Cheers
Mark.
room is neither large nor i need huge power, but below link inspired me to give a thought about bigger cones,
Zypher Avepa Sub - The not so little MONSTER!!
moreover a pro 18" costs more or less same price as a popular 10" or 12" home sub. in the above thread, the designer of lyrita speakers(which use fostex 6" fullrangers) agreed that 21" sub has integrated very well with fostex, reaching down to 25hz flat! i am not a bass freak but i spoke to the one who has auditioned this 21" sub that there is some magic in 25hz (not -3dB but 0dB flat). with this i could only guess bigger cones can reach lows easily without much of cone excursion thus low distortion. also it could serve as a coffee table!! :p
i will go through the thread you have mentioned
Thanks
 
People often ask why a 15" or 18" diameter open baffle woofer vs. small size closed box woofers/subwoofers. In theory you need about 4 times the cone area for equivalent performance SPL between open and closed back designs. The acoustical short circuit exhibited by an open back can be partially compensated via use of an H-baffle or such and electronic EQ for lower Q woofers. I aim for performance into the mid 30's hertz range for music (the key is to cover 41 Hz) and prosound woofers are ideal with higher SPL and extended upper frequency coverage vs. home audio subwoofers.

The merits of an open back woofer reside in their ability to create dipolar sound with no 'box talk'--instant attack and decay transients are plenty nice and you will hear the difference. Also dipoles typically don't excite room modes so integration into the room is easier than boxed speakers.
 
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room is neither large nor i need huge power, but below link inspired me to give a thought about bigger cones,
Zypher Avepa Sub - The not so little MONSTER!!
moreover a pro 18" costs more or less same price as a popular 10" or 12" home sub. in the above thread, the designer of lyrita speakers(which use fostex 6" fullrangers) agreed that 21" sub has integrated very well with fostex, reaching down to 25hz flat! i am not a bass freak but i spoke to the one who has auditioned this 21" sub that there is some magic in 25hz (not -3dB but 0dB flat). with this i could only guess bigger cones can reach lows easily without much of cone excursion thus low distortion. also it could serve as a coffee table!! :p
i will go through the thread you have mentioned
Thanks

Hi Sound,
Much depends on the type of music you're going to play as previously mentioned. Since your not a "bass freak", I'd urge some caution re selecting such a large bass driver.

I remain worried at the number of FAST (et al) projects that overlook the emittance limitations of large drivers, especially Subs.

Large Sub Woofers, Especially Pro versions with high power handling will likely have compromised micro-resonant emittance. Their cone structures will be relatively high mass, the cone substrate under oscillation won't carry the sub-resonant pattern within the main carrier signal running across its surface. The result is much musical detail is lost.

One tip is to compare moving masses (MMS), see which makes and types of sort/size your looking at, offers the lowest MMS. That at least will give some chance of finding a large driver that might have a more sympathetic emittance match. Such a driver might sacrifice some power handling compared to others, but for most home uses, lower power handling in large drives shouldn't cause any difficulties. Naturally, there are other design factors to consider, as mentioned by other members, but this one shouldn't be overlooked.

The coffee table might be the best yet!!

Cheers
Mark.
 
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