Virtalahde,
I didn't said that because Visaton wouldn't have any good drivers in their lineup. I just don't know. First one we tested didn't look that good while it's in their "high end" line and is pretty expensive unit. I just don't like investing pigs in a bag.
David,
Intresting measurements. 200Hz could be fine but what about the slope? Is 2nd order L&R enough or would it have to be steeper?
This is pretty difficult thing to consider. Higher gentle slope gives less group delay, propably improves driver integration and results smoother vertical directivity. On the other hand lower cross allows heavier woofers with more displacement and leaves some advantage for the AR cabinet and mids. Basically that MTM midsection can be run down to around 150Hz but I don't know how linear it would behave down there. At least crossoverslope should be steep. And with 150Hz cross there isn't that much point in WMTMW config, it would make it easier to drop the other woofer closer to floor as well and go for that Wilson Alex concept.
According to my room simulations woofers should be as close to frontwall as possible so first reflection from that boundary is as closely in same phase as the direct sound as high frequency as possible. Basically this gives pretty good results up to 100Hz or so and therefore it's formed one of the most favourite spots for a subwoofer in a system.
That's also one possibility. Stack a selected woofers in a closed, preferring pretty flat, cabinets and place them as close to frontwall as possible. Then have the MTM top and place them in regular listening triangle just as any other Odin size MTM 2-way. Naturally this requires some digital delay to get it working.
100Hz is too low cross but perhaps 120-150Hz 4th order could work. I've also checked out some heavy duty PA woofers for the task and cabinet could be something like the Audio Physic Minos allthought with only single woofer per box.
Of cource there is a flipside to all this. It doesn't have the vertical directivity of a WMTMW, more group delay and it leaves Behringer DCX permanent part of the system.
So, what's the biggest "boogie"? Floor reflections, less force at the bottom octave, bigger system.. 🙂
Harry,
That Snell sure looks intresting. Not a bad review...
Personally I'd be considering multiple 8" woofers over twin 10"s since it leaves cabinet narrow. But I'd like to stick with manufacturers I can invest from EU area, prefering Finland. Peerless, Seas, Vifa, Scan Speak. Pretty much what we've discussed here.
Jussi
I didn't said that because Visaton wouldn't have any good drivers in their lineup. I just don't know. First one we tested didn't look that good while it's in their "high end" line and is pretty expensive unit. I just don't like investing pigs in a bag.
David,
Intresting measurements. 200Hz could be fine but what about the slope? Is 2nd order L&R enough or would it have to be steeper?
This is pretty difficult thing to consider. Higher gentle slope gives less group delay, propably improves driver integration and results smoother vertical directivity. On the other hand lower cross allows heavier woofers with more displacement and leaves some advantage for the AR cabinet and mids. Basically that MTM midsection can be run down to around 150Hz but I don't know how linear it would behave down there. At least crossoverslope should be steep. And with 150Hz cross there isn't that much point in WMTMW config, it would make it easier to drop the other woofer closer to floor as well and go for that Wilson Alex concept.
According to my room simulations woofers should be as close to frontwall as possible so first reflection from that boundary is as closely in same phase as the direct sound as high frequency as possible. Basically this gives pretty good results up to 100Hz or so and therefore it's formed one of the most favourite spots for a subwoofer in a system.
That's also one possibility. Stack a selected woofers in a closed, preferring pretty flat, cabinets and place them as close to frontwall as possible. Then have the MTM top and place them in regular listening triangle just as any other Odin size MTM 2-way. Naturally this requires some digital delay to get it working.
100Hz is too low cross but perhaps 120-150Hz 4th order could work. I've also checked out some heavy duty PA woofers for the task and cabinet could be something like the Audio Physic Minos allthought with only single woofer per box.
Of cource there is a flipside to all this. It doesn't have the vertical directivity of a WMTMW, more group delay and it leaves Behringer DCX permanent part of the system.
So, what's the biggest "boogie"? Floor reflections, less force at the bottom octave, bigger system.. 🙂
Harry,
That Snell sure looks intresting. Not a bad review...
Personally I'd be considering multiple 8" woofers over twin 10"s since it leaves cabinet narrow. But I'd like to stick with manufacturers I can invest from EU area, prefering Finland. Peerless, Seas, Vifa, Scan Speak. Pretty much what we've discussed here.
Jussi
Oh by the way: what do you guys think about Qtc of a closed cabinet? Different builders have their different preferences. Some prefer 0,6, some use schoolbook 0,7, some need 0,5.
When it comes to FR it's easy to fix response shape for certain Q-value, for example Linkwitz transform is a topology just for the job. Naturally this isn't as good result as driver in naturally big cabinet with actual Q. Distorsion and compression numbers are uglier if driver is smaller cabinet that required and electronical tricks don't effect that.
But what about displacement. Today there are plenty of longthrow drivers with traditionally "strange" parametres. For example normal XLS line woofers fit into extremely small, even few litres, closed cabinets. Compared to drivers displacement it should give certain shape for the response but it also causes dramatical pressure differences inside the cabinet if whole displacement is used. And as comparison for example Scan Speaks classic woofers need pretty large box for certain Q-value. This leaves pressure changes much smaller inside the cabinet.
So here's the question: would it be ok to use large cabinet requiring decent displacement driver in smaller cabinet and fix the responseshape electronically and at the sametime prefer larger that necessary box for large displacement small cabinet requiring driver and maybe even fix the Q-value larger electronically?
Messy text once more, hope you find the idea if there is any...
Jussi
When it comes to FR it's easy to fix response shape for certain Q-value, for example Linkwitz transform is a topology just for the job. Naturally this isn't as good result as driver in naturally big cabinet with actual Q. Distorsion and compression numbers are uglier if driver is smaller cabinet that required and electronical tricks don't effect that.
But what about displacement. Today there are plenty of longthrow drivers with traditionally "strange" parametres. For example normal XLS line woofers fit into extremely small, even few litres, closed cabinets. Compared to drivers displacement it should give certain shape for the response but it also causes dramatical pressure differences inside the cabinet if whole displacement is used. And as comparison for example Scan Speaks classic woofers need pretty large box for certain Q-value. This leaves pressure changes much smaller inside the cabinet.
So here's the question: would it be ok to use large cabinet requiring decent displacement driver in smaller cabinet and fix the responseshape electronically and at the sametime prefer larger that necessary box for large displacement small cabinet requiring driver and maybe even fix the Q-value larger electronically?
Messy text once more, hope you find the idea if there is any...
Jussi
Jussi,
Well, I don't know either so I'm trying to find other people's experiences. So far I haven't really found anything except some 10" Scan-Speaks that would do the trick here.
But I've been thinking if I'm compromising my lower midrange in the quest for f3 of 30Hz in closed cabinet and if LT is just going to mess the midrange up.
Maybe I should just go for f3 of ~45Hz (much easier) and add the sub like normal people do. 😀 Then, I could easily use a Seas W26 (or maybe even the L26, I found a better photo and now it isn't looking that bad to me anymore..)
Or perhaps the Scan-Speak 25W/8565-00, f3~40Hz in a closed cabinet. Might also be a better sonical match to the Seas paper midrange.
I'm going to try them all, but Qtc of 0,6 seems good to me right now..
Well, I don't know either so I'm trying to find other people's experiences. So far I haven't really found anything except some 10" Scan-Speaks that would do the trick here.
But I've been thinking if I'm compromising my lower midrange in the quest for f3 of 30Hz in closed cabinet and if LT is just going to mess the midrange up.
Maybe I should just go for f3 of ~45Hz (much easier) and add the sub like normal people do. 😀 Then, I could easily use a Seas W26 (or maybe even the L26, I found a better photo and now it isn't looking that bad to me anymore..)
Or perhaps the Scan-Speak 25W/8565-00, f3~40Hz in a closed cabinet. Might also be a better sonical match to the Seas paper midrange.
I'm going to try them all, but Qtc of 0,6 seems good to me right now..
With 2nd order 200Hz Linkwitz Riley cross vertical directivity is in decent level using WMTMW or WWMTMWW configuration. This might be a good compromisse between group delay, driver selection (allows semi-heavy-duty woofers) and AR advantage.
Twin XXLS 10" or quad 8" (Seas L22, CD22). Inductance shouldn't be at dominant position with such cross (distorsion) and it still leaves midrange drivers pretty excursionfree for clear midrange.
Basically there is not that bad about 4th order as well but it leaves vertical directivity a bit uneven 400-600Hz.
Are Seas or DST prices rised recently? Finnish Seas distributors priced have popped 1.7 pretty tremendously. W18E Excel used to be 172 euros each, now 214 euros each. Prestige series L22 and CD22 are also up. I remember CD22 being 94 euros or so before and now 117 euros. Darn.
Virtalahde,
Whats with you and non-metal midranges? 🙂
Jussi
Twin XXLS 10" or quad 8" (Seas L22, CD22). Inductance shouldn't be at dominant position with such cross (distorsion) and it still leaves midrange drivers pretty excursionfree for clear midrange.
Basically there is not that bad about 4th order as well but it leaves vertical directivity a bit uneven 400-600Hz.
Are Seas or DST prices rised recently? Finnish Seas distributors priced have popped 1.7 pretty tremendously. W18E Excel used to be 172 euros each, now 214 euros each. Prestige series L22 and CD22 are also up. I remember CD22 being 94 euros or so before and now 117 euros. Darn.
Virtalahde,
Whats with you and non-metal midranges? 🙂
Jussi
Here's a Lynn Olson quote which might be interesting:
"The 8" Scan-Speak 21W/8554, probably one of the best 8" drivers in the world, has an inductance of 0.1mH, which is far lower than the 8" Vifa P21W0-20-08, which has in inductance of 0.9mH. Both are excellent drivers; the Scan-Speak, though, is almost certainly going to have more transparent sound when asked to play bass and midrange at the same time."
You can read the whole article here:
http://www.nutshellhifi.com/library/speaker-design2.html
--> Magnetic non-linearities
So subwoofers with 1-4mH voice coil inductance are probably not a good choice for high x-over.
"The 8" Scan-Speak 21W/8554, probably one of the best 8" drivers in the world, has an inductance of 0.1mH, which is far lower than the 8" Vifa P21W0-20-08, which has in inductance of 0.9mH. Both are excellent drivers; the Scan-Speak, though, is almost certainly going to have more transparent sound when asked to play bass and midrange at the same time."
You can read the whole article here:
http://www.nutshellhifi.com/library/speaker-design2.html
--> Magnetic non-linearities
So subwoofers with 1-4mH voice coil inductance are probably not a good choice for high x-over.
Inductance VC certainly very important parameter, but it is not necessary to look at value resulted in specifications - there is a chance to be mistaken so-as there are some different ways for its definition, look even at values Peerless Exlusive and look at its impedance curve. Therefore here only one true method - to not look at values, and to look at a curve of an impedance and calculate "Le" directly from curve if needed.
And one more... Not too and badly relatively high value Le is by itself. A change in this value with different positions of coil in the magnetic system this is what is actually bad.
And one more... Not too and badly relatively high value Le is by itself. A change in this value with different positions of coil in the magnetic system this is what is actually bad.
Intresting issue. I guess inductance has some influence to overall sound but how significant problem is it say below 200Hz? At least I'd consider brutal displacement more crusial at that frequencyrange if I'd have to choose between low inductance and bigger displacement.
Inductance caused distorsion shouldn't be a problem there but what about this drivers "slowmotion" compared to smaller Le values?
Audio Technology also has very low inductance values in their models. Shame they are so darn expensive.
I checked and its reality: Seas has raised their prices dramatically. Looks like DST products are even more competitive now... Two 8" HDS woofers in price of one Seas Prestige. At least to those who consider costs.
Jussi
Inductance caused distorsion shouldn't be a problem there but what about this drivers "slowmotion" compared to smaller Le values?
Audio Technology also has very low inductance values in their models. Shame they are so darn expensive.
I checked and its reality: Seas has raised their prices dramatically. Looks like DST products are even more competitive now... Two 8" HDS woofers in price of one Seas Prestige. At least to those who consider costs.
Jussi
So it looks like a compromisse once more. Here few of the candidates with quickly thought advantages and disadvantages:
HDS Nomex 8", four on each side:
+ affordable
+ cutted flange (205mm, allows narrow cabinet)
+ efficient
+ small cabinet requirements, vented possibility
? decent inductance
- medium excursion capacity
L22/CD22 Seas, four on each side:
+ small cabinet requirements
+ nice excursion capacity for its size
? enough for HT use
- high inductance
- Prestige drivers prices rised
21W/8555 Scan Speak (used), pair on each side:
+ low inductance
+ low distorsion
+ works nicely in closed cabinet
? some problems 200-300Hz range
- not enough grunt for HT use
All of the 8" have the advantage of allowing narrow cabinet or baffle at least
25W/8565 Scan Speak (used), pair on each side:
+ low inductance
+ low distorsion
+ low mms, low loss suspension (my personal perversions)
? maybe some problems 200-300Hz range (since its the bigbrother of 21W)
? maybe enough grunt for HT use
- requires more cabinetspace than available (Linkwitz-transform)
Peerless 10" XXLS, pair on each side:
+ enough grunt for HT use
+ high SPL and dynamics capacity (displacement)
+ low distorsion
? top end extension
- high inductance
I'm sure I've missed some important points here so feel free to add.
Jussi
HDS Nomex 8", four on each side:
+ affordable
+ cutted flange (205mm, allows narrow cabinet)
+ efficient
+ small cabinet requirements, vented possibility
? decent inductance
- medium excursion capacity
L22/CD22 Seas, four on each side:
+ small cabinet requirements
+ nice excursion capacity for its size
? enough for HT use
- high inductance
- Prestige drivers prices rised
21W/8555 Scan Speak (used), pair on each side:
+ low inductance
+ low distorsion
+ works nicely in closed cabinet
? some problems 200-300Hz range
- not enough grunt for HT use
All of the 8" have the advantage of allowing narrow cabinet or baffle at least
25W/8565 Scan Speak (used), pair on each side:
+ low inductance
+ low distorsion
+ low mms, low loss suspension (my personal perversions)
? maybe some problems 200-300Hz range (since its the bigbrother of 21W)
? maybe enough grunt for HT use
- requires more cabinetspace than available (Linkwitz-transform)
Peerless 10" XXLS, pair on each side:
+ enough grunt for HT use
+ high SPL and dynamics capacity (displacement)
+ low distorsion
? top end extension
- high inductance
I'm sure I've missed some important points here so feel free to add.
Jussi
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