Well, one pretty High WAF or even WAF Approved (tm) solution would be using single large woofer in flat small baffle. Triangle shape and cloth at all sides, looks the same from different angles and therefore allows turning it for best listening position performance. For example 15-18" driver could do the job. Naturally max SPL isn't as high as for example that six 12" SLS solution while cost is easily the same but size is much more compact.
But I don't know that many large woofers that could do the job. I know many large PA woofers can do it and don't have any problems with 150-200Hz lowpass but at the same time linear xmax is pretty small. Single TC Sounds TC2+ 12" can hammer almost the same displacement. Some large excursion models would have more brute SPL but I'm not so sure how they could handle 150-200Hz and they also very often have pretty heavy mms which causes whole thing rattle and more more.
Any suggestions from 15-18" sizes?
Open basket, good xmax, low distorsion, nice efficiency. I'd prefer having seamless integration to midrange at 150-200Hz range over brute SPL and deep bass extension. But sure, both would be nice.
Hans,
Sounds pretty intresting idea but it has few problems. For example positioning is pretty difficult to experiment. 😉
Jussi
But I don't know that many large woofers that could do the job. I know many large PA woofers can do it and don't have any problems with 150-200Hz lowpass but at the same time linear xmax is pretty small. Single TC Sounds TC2+ 12" can hammer almost the same displacement. Some large excursion models would have more brute SPL but I'm not so sure how they could handle 150-200Hz and they also very often have pretty heavy mms which causes whole thing rattle and more more.
Any suggestions from 15-18" sizes?
Open basket, good xmax, low distorsion, nice efficiency. I'd prefer having seamless integration to midrange at 150-200Hz range over brute SPL and deep bass extension. But sure, both would be nice.
Hans,
Sounds pretty intresting idea but it has few problems. For example positioning is pretty difficult to experiment. 😉
Jussi
As for pure displacement seems like a 15" woofer with +-25mm linear excursion would have very similar SPL capacity as six 12" SLS drivers and this could be achieved in very compact solution.
But where to find such a driver. It could also be a 18" model which reduces excursion need a bit. 200-250g mms seems unavoidable in such drivers and how do they handle bass up to 150-200Hz?
Jussi
But where to find such a driver. It could also be a 18" model which reduces excursion need a bit. 200-250g mms seems unavoidable in such drivers and how do they handle bass up to 150-200Hz?
Jussi
Member
Joined 2003
Jussi,
A single 15" per channel is the track I'm on to get bass with a small baffle. (xo to IB below 40-50Hz.) One driver I'm considering has about 25mm xmax, copper shorting ring, and stiff aluminum cone with high break-up is the Soundsplinter RL-p15 (from TC Sounds). However, it is not efficient so it needs a lot of power. Also, VC inductance looks high so I am concerned that they may not perform well at 200Hz. I've asked Soundsplinter to send me the impedance curve before I buy and they have agreed to do that, but I don't yet have the curve.
One strong possibility (supposedly) coming late spring or early summer this year is an aluminum 15"HF from Parts Express with maybe 15-20mm xmax. The 10" and 12" (with three shorting rings) already on the market are reported to be great performers and are very reasonably priced.
Paul
A single 15" per channel is the track I'm on to get bass with a small baffle. (xo to IB below 40-50Hz.) One driver I'm considering has about 25mm xmax, copper shorting ring, and stiff aluminum cone with high break-up is the Soundsplinter RL-p15 (from TC Sounds). However, it is not efficient so it needs a lot of power. Also, VC inductance looks high so I am concerned that they may not perform well at 200Hz. I've asked Soundsplinter to send me the impedance curve before I buy and they have agreed to do that, but I don't yet have the curve.
One strong possibility (supposedly) coming late spring or early summer this year is an aluminum 15"HF from Parts Express with maybe 15-20mm xmax. The 10" and 12" (with three shorting rings) already on the market are reported to be great performers and are very reasonably priced.
Paul
i'd say this is the solution, don't know about the frequency response, though at a sound quality level i find that it is a weird idea wanting to use such a big excursion driver up around 250 hz . sure "PA" like woofers looks more orientated for this kind of things
aaah i remember a VERY expensive driver if cost is no object :
Davis 40RCA15
sure if i had the money i would build something with this
aaah i remember a VERY expensive driver if cost is no object :
Davis 40RCA15
sure if i had the money i would build something with this
Paul W said:
Paul..
..you might consider contacting Bert at BD-Designs about the use and design of a compound BD-15 arangement (i.e. something like a Legacy Audio Whisper.. but with the aperiodic venting/cardoid for the rear driver if desired).
http://www.legacy-audio.com/2004/whisper.html
Note: that the side-edge profile is "open" (free-air) between the two drivers.
http://www.bd-design.nl/index.html?lang=en-uk&target=d82.html
Note: that he uses the BD-15's free-air dipole in his Quasar MkIII design. (..compensation provided via the BD30.)
Well, desinging a 3-way system with dipolebass. It isn't easy without compromisses.
I thought I could try to extend AR midrange response down to 100Hz or so but I think it's just pushing it. I'd prefer a bit higher cross, 150-200Hz and have the mids play their own range without excursion problems and EQ.
For those very high excursion drivers I have my doubts can they play solid and accurate bass even at bottom of the range. Sure, they deliver lots of SPL within linear range but without detail, punch and integration to upper range it's just noise. At least to me it is.
For example Italian RCF PA stuff are well available here in Finland. Two 18" drivers cost about 600-700 euros depending on model. For example old servant L18P300 is measurably very good up to 500Hz. Response, distorsion and so on. I don't attend to use them that high but operational clean range higher doesn't hurt.
Personally I'd compromisse brute SPL and deepest bass extension for integration and higher cross to play safe with mids. Here is one RCF model I've considered:
http://www.rcf.it/VediMacro.phtml?IDMacro=2723&m1=1&m2=0&m3=1_0_2
Local distributor recommended this one for dipole application. It has vents behind the spider so excursion should be noiseless when it comes to turbulence. Linear excursion +-8,5mm which isn't much these days but is quite normal value in PA woofers. This along with 1220cm2 cone gives displacement pretty identical to Orions or Finnish Gradients (www.gradient.fi) Revolution model. Both are mensioned to be "full range" systems with their bass response. Placing such separated single woofer along sidewall I'd have about 6dB more which is also significant. G401 also has +-25mm maximum excursion before damage and those drivers have very stiff progressive suspensions so that excursion is also pretty difficult to achieve. Sure it causes compression but it doesn't break anything. This I'd consider a virtue since drivers would be behind cloth and it's hard to tell when they are really running out of breath, just as a safemeasure.
So, how adequate Orion bass is? What about if it's boosted by 6dB?
Orion + 6dB, is there even worry about having 18" PA woofer running out of gap in normal listening situations?
At least down to 40Hz it seems to be pretty strong candidate. I used Siegfried Linkwitzs SPL calculator and got a value of 94dB at 40Hz by running 1220cm2 cone +-8,5mm. Floor adds 6dB while it limits radiation pattern into half space, sidewall would add another 6dB by limiting radiation to quarter space, up to 6dB more by having stereowoofers... Which already makes 112dB. I guess room does drain some from there (reflection from frontwall) and listening distance is more than 1m but how does that sound overall? Should I still consider pretty equally priced but whole lot bigger systems having stacked SLS woofers hanging on walls or ceiling?
Naturally below 40Hz capacity isn't that hot. 30Hz would result 105dB and 20Hz much less. But the bright sides...
Thing is very compact, about 50cm wide, triangle shape from the top, looks identical from different directions, easy to move and turn for optimum listening position performance, room order can be changed and WAF remains pretty strong.
Jussi
I thought I could try to extend AR midrange response down to 100Hz or so but I think it's just pushing it. I'd prefer a bit higher cross, 150-200Hz and have the mids play their own range without excursion problems and EQ.
For those very high excursion drivers I have my doubts can they play solid and accurate bass even at bottom of the range. Sure, they deliver lots of SPL within linear range but without detail, punch and integration to upper range it's just noise. At least to me it is.
For example Italian RCF PA stuff are well available here in Finland. Two 18" drivers cost about 600-700 euros depending on model. For example old servant L18P300 is measurably very good up to 500Hz. Response, distorsion and so on. I don't attend to use them that high but operational clean range higher doesn't hurt.
Personally I'd compromisse brute SPL and deepest bass extension for integration and higher cross to play safe with mids. Here is one RCF model I've considered:
http://www.rcf.it/VediMacro.phtml?IDMacro=2723&m1=1&m2=0&m3=1_0_2
Local distributor recommended this one for dipole application. It has vents behind the spider so excursion should be noiseless when it comes to turbulence. Linear excursion +-8,5mm which isn't much these days but is quite normal value in PA woofers. This along with 1220cm2 cone gives displacement pretty identical to Orions or Finnish Gradients (www.gradient.fi) Revolution model. Both are mensioned to be "full range" systems with their bass response. Placing such separated single woofer along sidewall I'd have about 6dB more which is also significant. G401 also has +-25mm maximum excursion before damage and those drivers have very stiff progressive suspensions so that excursion is also pretty difficult to achieve. Sure it causes compression but it doesn't break anything. This I'd consider a virtue since drivers would be behind cloth and it's hard to tell when they are really running out of breath, just as a safemeasure.
So, how adequate Orion bass is? What about if it's boosted by 6dB?
Orion + 6dB, is there even worry about having 18" PA woofer running out of gap in normal listening situations?
At least down to 40Hz it seems to be pretty strong candidate. I used Siegfried Linkwitzs SPL calculator and got a value of 94dB at 40Hz by running 1220cm2 cone +-8,5mm. Floor adds 6dB while it limits radiation pattern into half space, sidewall would add another 6dB by limiting radiation to quarter space, up to 6dB more by having stereowoofers... Which already makes 112dB. I guess room does drain some from there (reflection from frontwall) and listening distance is more than 1m but how does that sound overall? Should I still consider pretty equally priced but whole lot bigger systems having stacked SLS woofers hanging on walls or ceiling?
Naturally below 40Hz capacity isn't that hot. 30Hz would result 105dB and 20Hz much less. But the bright sides...
Thing is very compact, about 50cm wide, triangle shape from the top, looks identical from different directions, easy to move and turn for optimum listening position performance, room order can be changed and WAF remains pretty strong.
Jussi
Member
Joined 2003
You guys make a good point about the pro-drivers. I have a 15" JBL pro in a test baffle now and it performs very nicely at 250Hz and will probably go higher very gracefully. With "soft clipping" in many of the pro woofers, placing the priority on the first 10 watts rather than the last 100 is certainly a viable strategy.
Scott,
I am reading the Whisper to fire the out of phase signal to the sides, correct?
Paul
Scott,
I am reading the Whisper to fire the out of phase signal to the sides, correct?
Paul
Darn. That stack of SLS still feels tempting. Such solution has some linesource attributes and could help even up the bass-lowmid range even further. One Finnish builder has four 12" SLS in straight baffle, running them up to 200Hz and has very smooth roomresponse up to 200-250Hz where single 7" coax takes over.
But placing such baffle isn't that easy. I'd need a deep room where woofercolumns can be along sidewalls, even bolted into the sidewalls which would make them solid part of decoration but also allows some solutions to hide them better. For example whole thing could be attached to the wall and not connected to the floor at all. This makes for example housekeeping easier. But the positioning overall. Would be a advantage to have equal space behind the woofers and frontwall and behind the listener and rearwall. Still placing them is very critical. Room order can't be changed that easily after that. As for performance 6-8 12" SLS woofers have quite significant response, both in brute SPL along with 150-250Hz extension without problems.
Darn.
Jussi
But placing such baffle isn't that easy. I'd need a deep room where woofercolumns can be along sidewalls, even bolted into the sidewalls which would make them solid part of decoration but also allows some solutions to hide them better. For example whole thing could be attached to the wall and not connected to the floor at all. This makes for example housekeeping easier. But the positioning overall. Would be a advantage to have equal space behind the woofers and frontwall and behind the listener and rearwall. Still placing them is very critical. Room order can't be changed that easily after that. As for performance 6-8 12" SLS woofers have quite significant response, both in brute SPL along with 150-250Hz extension without problems.
Darn.
Jussi
Paul W said:
Basically: the front driver's rear is out-of-phase and the rear driver's front is in-phase.. i.e. they "null" (..and it is open..i.e. free-air via that "gap" at the sides where they "null"). (..functionally a "push-push" design where they are both operating in-phase on a forward pulse.)
Whisper:
Forward in-phase/null/Rear out-of-phase.
A normal free-air dipole would be:
Forward in-phase/Rear out-of-phase.
(both designs opererate free-air for all of their output.)
Among other things I believe that this increases directivity somewhat over a cardoid. In the Whisper then its a hypercardoid with more rear out-of-phase output than a standard hypercardoid. With your proposed rear driver aperiodic dampening it is a hypercardoid with less (or no) real rear out-of-phase output.
The BD-Design driver doesn't have a lot of x-max, BUT it is very efficient, lots of force, and a VERY low mms (for the sd).. which usually makes for a better sounding midbass driver. Moreover they are 16 ohm drivers, so paralleling in this configuration with an amp with a low output impeadace gives an extra 3db.
Ok. Seems like BMS Pro has some 18" drivers worth considering. 18N850 has 1212cm2 cone, +-13mm linear excursion, 97dB efficiency, neo motor and costs 380 euros each here. RCF LF18G401 which was also recommended is very closely at the same pricerange but has only 2/3 of the displacement capacity. Unfortunately BMS also has increased mms up to 300g but response is smooth above 200Hz and distorsion is also handled nicely.
Actually that distorsion is displayed a bit different than I'm used to. Sure it has 2nd and 3rd harmonic distorsion, -20dB and -30dB levels which isn't that good values but the driver is installed into 150 litres closed cabinet and full 1000W power is runned through it so SPL is around 130dB which means that -20dB and -30dB levels are still pretty good. I guess I'd listen a bit lower level and therefore have much better distorsion results as well.
As for brute displacement those leave only 3dB behind that 6x12" SLS stack and can still be installed into a compact cabinet, movable and turnable. Basket is also open behind the spider so turbulence noise should be avoided.
Jussi
Actually that distorsion is displayed a bit different than I'm used to. Sure it has 2nd and 3rd harmonic distorsion, -20dB and -30dB levels which isn't that good values but the driver is installed into 150 litres closed cabinet and full 1000W power is runned through it so SPL is around 130dB which means that -20dB and -30dB levels are still pretty good. I guess I'd listen a bit lower level and therefore have much better distorsion results as well.
As for brute displacement those leave only 3dB behind that 6x12" SLS stack and can still be installed into a compact cabinet, movable and turnable. Basket is also open behind the spider so turbulence noise should be avoided.
Jussi
Member
Joined 2003
Jussi,
The 18N850 does look good. Inductance is low and impedance flat. I wonder if response wiggles above 250Hz are because they measured on an actual small box rather than large baffle with small box behind baffle as some other mfg do???
If you want one with lower Mms, take a look at the B&C 18TBX100. In many other ways 18N seems better, but 18TBX has only 2/3 Mms of 18N.
Paul
The 18N850 does look good. Inductance is low and impedance flat. I wonder if response wiggles above 250Hz are because they measured on an actual small box rather than large baffle with small box behind baffle as some other mfg do???
If you want one with lower Mms, take a look at the B&C 18TBX100. In many other ways 18N seems better, but 18TBX has only 2/3 Mms of 18N.
Paul
I don't know whats causing that wiggle. Could be even more severe problem but at least impedance graph doesn't so signs of cone resonance. With 200Hz 4th order cross it should be managed.
There are plenty of PA drivers with less mms than 18N but they lack some excursion capacity as well. In this mather seems like PA drivers move closer towards normal hifi-drivers when excursion starts to rise. Mms rises as well, at some point efficiency drops and so on.
That stack of SLS has some advantages in vertical directivity and perhaps it could run higher at frequency than 18N. But sure it makes a lot bigger solution with potential positioning problems. Price would be the same thought...
Jussi
There are plenty of PA drivers with less mms than 18N but they lack some excursion capacity as well. In this mather seems like PA drivers move closer towards normal hifi-drivers when excursion starts to rise. Mms rises as well, at some point efficiency drops and so on.
That stack of SLS has some advantages in vertical directivity and perhaps it could run higher at frequency than 18N. But sure it makes a lot bigger solution with potential positioning problems. Price would be the same thought...
Jussi
And with good reason I might add 🙂Jussi said:
Have you seen this design as well:
http://home.wanadoo.nl/dezaire/dipoolbas/dipole_bass.htm
It uses two SLS12 as dipoles.
I heard it on the Dutcht DIY event 2006 (http://home.versatel.nl/ddiy_2005/, see link at left frame 'Foto's 2006'). It was one of the best design there, if not the best, 'competing' with a few high quality design. Quality of the displayed designs tend to vary wildy at such events, ranging from 'needs (a lot of) work' 😉 to 'highend'. For instance, I heard Guido Tent's cdp and speaker combination also received very good feedback from the attendees. There where a lot of dipole designs this year which was a nice combination with the presentation I gave on dipole designs. Next year I hope to display my current design which has been on the drawing board for quite a while. It will include 3 XXLS12" per side in dipole.
Hans L said:
Yep. Would make a better match in room if those bass panels could be placed optimally. Also six motors against single big one, way much more efficiency (specially at bottom end where PA woofers low Q eats efficiency), less cone excursion and about 450g total mms.
Nice. I'd say most of the directivity advantage is in bass range, up to 300-400Hz or so. But naturally overall results is even better if also the rest of the spectrum is handleded with smooth behaving directional design.
Jussi
Well. New apartment invested (no need to congratulate) and things develop. Livingroom 5,2 x 3,7m, 2,6m high. Speakers are going to be along that 5,2m side flanking the tv set. Sofa on the other side. Nice distance to both sidewalls but distance from speakers to frontwall and listening spot to rear wall is limited or listening triangle runs really small.
Now some ideas. I have those MTM AR cabinets coming up, Esotars and W18E:s are standing by for action. Estimated bottom extension for midrange is 150Hz.
As cardioid or hypercardioid transducers (depending on AR tuning) mid-treble top unit should be pretty secure from frontwall reflections. Rearwall can be acoustically treated and I'm prepared to make basstraps for both rear corners if necessary.
Any recommendations for nice high resolution, adequate high output, deep bass extension bass solution?
I know I can't have dipoles radiating front-back direction and expect deep bass but thats one thing I can live with. One solution is still this BMS Pro 18N850 woofer on each side running in small triangle shape (from the top) flat baffle and have dipole radiation pattern. Other relatively strong candicate is sidefiring woofer(s) that can also operate as build together stands for the top unit. This kind of solution is used by Finnish Amphion (www.amphion.fi), AR MTM plus sidefiring woofer is the same config they use in their flagship Krypton.
At least lower or even both crosses are going to be active so bass level and possible EQ shouldn't be a problem.
Ideas and recommendations would be welcome. Totally different approaches are also very welcome, I know I haven't thought this thing all the way through.
Jussi
Now some ideas. I have those MTM AR cabinets coming up, Esotars and W18E:s are standing by for action. Estimated bottom extension for midrange is 150Hz.
As cardioid or hypercardioid transducers (depending on AR tuning) mid-treble top unit should be pretty secure from frontwall reflections. Rearwall can be acoustically treated and I'm prepared to make basstraps for both rear corners if necessary.
Any recommendations for nice high resolution, adequate high output, deep bass extension bass solution?
I know I can't have dipoles radiating front-back direction and expect deep bass but thats one thing I can live with. One solution is still this BMS Pro 18N850 woofer on each side running in small triangle shape (from the top) flat baffle and have dipole radiation pattern. Other relatively strong candicate is sidefiring woofer(s) that can also operate as build together stands for the top unit. This kind of solution is used by Finnish Amphion (www.amphion.fi), AR MTM plus sidefiring woofer is the same config they use in their flagship Krypton.
At least lower or even both crosses are going to be active so bass level and possible EQ shouldn't be a problem.
Ideas and recommendations would be welcome. Totally different approaches are also very welcome, I know I haven't thought this thing all the way through.
Jussi
Member
Joined 2003
Hi Jussi,
I have a pair of the 18N850's on order (thanks for the discovery) so I'll be able to give you first impressions of build quality in a week or so. BMS never answered my inquiry about the FR dip, and distributor didn't know the answer either, so a bit of a gamble...but that is life 🙂.
Paul
I have a pair of the 18N850's on order (thanks for the discovery) so I'll be able to give you first impressions of build quality in a week or so. BMS never answered my inquiry about the FR dip, and distributor didn't know the answer either, so a bit of a gamble...but that is life 🙂.
Paul
Paul W said:
Great! Are you using them for dipole duty or something else? Let me know how they turn out.
Dipole is a compromisse itself. It can work very well but it needs space behind and front of it. In this mather monopolebass is propably more universal since it works at least in some level in any situation. Place a dipole very close to wall and you won't have any bass, it just doesn't work.
Jussi
Member
Joined 2003
Jussi,
I'll try them both AR and dipole...either way they will be more than 1 meter from any wall. They will xo to IB subs at about 40Hz...dipole is impractical below that.
Paul
I'll try them both AR and dipole...either way they will be more than 1 meter from any wall. They will xo to IB subs at about 40Hz...dipole is impractical below that.
Paul
Paul,
Did you got those BMS Pro woofers yet? Any first impressions on overall build quality etc?
Jussi
Did you got those BMS Pro woofers yet? Any first impressions on overall build quality etc?
Jussi
Member
Joined 2003
Hi Jussi,
Yes, there was a little delay, but I received them yesterday afternoon.
Overall build quality looks very good. The cone is extremely stiff even compared to JBL pro driver. Cone has many concentric rings on the front side, back side of cone is coarse texture like some ScanSpeak drivers. All adhesive joints are very clean and neat. Voice coil leads are attached to spyder between VC and terminals. Aluminum frame is lightweight, but design appears structurally stiff. Neo magnet assembly looks rather small and flimsy in BMS photo, but it is actually the most impressive part of the driver...oversized pole vent with very aerodynamic shape. Spyder vents are separate. I think it will be fairly easy to damp any vent noise, especially with AR. My largest concern is the oversized dust cap which appears to be fiberglass...it does not seem as stiff as the cone, so I am a little concerned that it might breakup too soon.
I hope to get at least impedance sweep this weekend otherwise it may be almost a month before I have another chance.
How is your design coming along?
Paul
Yes, there was a little delay, but I received them yesterday afternoon.
Overall build quality looks very good. The cone is extremely stiff even compared to JBL pro driver. Cone has many concentric rings on the front side, back side of cone is coarse texture like some ScanSpeak drivers. All adhesive joints are very clean and neat. Voice coil leads are attached to spyder between VC and terminals. Aluminum frame is lightweight, but design appears structurally stiff. Neo magnet assembly looks rather small and flimsy in BMS photo, but it is actually the most impressive part of the driver...oversized pole vent with very aerodynamic shape. Spyder vents are separate. I think it will be fairly easy to damp any vent noise, especially with AR. My largest concern is the oversized dust cap which appears to be fiberglass...it does not seem as stiff as the cone, so I am a little concerned that it might breakup too soon.
I hope to get at least impedance sweep this weekend otherwise it may be almost a month before I have another chance.
How is your design coming along?
Paul
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