Hi,
I'm trying to understand the needs for an open mid-bass
(let say : 100 hz to 700, or 150 hz to 1000 max) without bafle (like Gradient designs)
My understanding is : better to avoid a large bafle because the bafle step.
My interogation is about the Thiels&Small data. Qts seems not to be so important in an active deszign with EQ for the low end. Instead Linkwitz seems prefer a low QTS around 0.3 with him last design. Some says the lower the better because the importance of the transcient here !
But with EQ, what about the needs with mms ? My understanding is a 5" mid driver in a classic design with box for let say 300 hz to 2500 doesn't need more than 2 or 3 mms for 100/105 DB output on transcient impulse.
For a bare mid-driver à la Gradient speaker, 12 " seems too big mainly because the weight of the cone in theory ! High efficienty needed because high spl can help with EQ in the low end. But here paper cone has a default : breaks mode at these low fhz values (100 to 200 min with strong EQ because OB need it below around 600 hz and more without bafle).
What should be the best trade off in normal living room (>25 square meter for a 150 hz to 800 hz mid bass:
- 8" or 10 " (220 to 350 cm² for Sd) more than 12" ? little horn bafle ?
- minimum mms needed to avoid audible distorsion ? (why to avoid box if distorsion!) in this low range (ears less senssible in the bass).
- hard metal cone with low breaks mode but higher slope to avoid resonances for the the upper driver or paper & higher SPL with the risk of more coloration and less details on the voices and little details & micro dynamic?
My trouble is whith the understanding of the SPL value on a datashhet : is it given at the max mms ? If so, it would say a driver given with 100 DB/3 mms is 3 times faster in dynamic than a 100 DB/9 mms ? If the amp is strong enough do I look at BL when it's time too choose the driver or for best transcient do I worth for the best BL also (= bigger Sd like a 12", high efficienty & paper) ? But which weight minimum to avoid break modes with paper in those frequencies ? (30 g for 220 Sd, much more ?)
The theory says Magnesium cone for those area but linkwitz gave up it with him last OB design for polypro cones... and goes with very low spl (around 85 for 220 Sd and 8")
Any ideas please ?
I'm trying to understand the needs for an open mid-bass
(let say : 100 hz to 700, or 150 hz to 1000 max) without bafle (like Gradient designs)My understanding is : better to avoid a large bafle because the bafle step.
My interogation is about the Thiels&Small data. Qts seems not to be so important in an active deszign with EQ for the low end. Instead Linkwitz seems prefer a low QTS around 0.3 with him last design. Some says the lower the better because the importance of the transcient here !
But with EQ, what about the needs with mms ? My understanding is a 5" mid driver in a classic design with box for let say 300 hz to 2500 doesn't need more than 2 or 3 mms for 100/105 DB output on transcient impulse.
For a bare mid-driver à la Gradient speaker, 12 " seems too big mainly because the weight of the cone in theory ! High efficienty needed because high spl can help with EQ in the low end. But here paper cone has a default : breaks mode at these low fhz values (100 to 200 min with strong EQ because OB need it below around 600 hz and more without bafle).
What should be the best trade off in normal living room (>25 square meter for a 150 hz to 800 hz mid bass:
- 8" or 10 " (220 to 350 cm² for Sd) more than 12" ? little horn bafle ?
- minimum mms needed to avoid audible distorsion ? (why to avoid box if distorsion!) in this low range (ears less senssible in the bass).
- hard metal cone with low breaks mode but higher slope to avoid resonances for the the upper driver or paper & higher SPL with the risk of more coloration and less details on the voices and little details & micro dynamic?
My trouble is whith the understanding of the SPL value on a datashhet : is it given at the max mms ? If so, it would say a driver given with 100 DB/3 mms is 3 times faster in dynamic than a 100 DB/9 mms ? If the amp is strong enough do I look at BL when it's time too choose the driver or for best transcient do I worth for the best BL also (= bigger Sd like a 12", high efficienty & paper) ? But which weight minimum to avoid break modes with paper in those frequencies ? (30 g for 220 Sd, much more ?)
The theory says Magnesium cone for those area but linkwitz gave up it with him last OB design for polypro cones... and goes with very low spl (around 85 for 220 Sd and 8")
Any ideas please ?
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No this is not correct. Using a narrow baffle, or even better NO baffle, improves the off-axis responses - they become much more like the on-axis response but lower in SPL. They do not have the dips and peaks that wide baffle or boxed speakers display. This helps to give them constant directivity.Hi,
I'm trying to understand the needs for an open mid-bass
My understanding is : better to avoid a large bafle because the bafle step.
Qts is important. There are tradeoffs that you should understand. In a boxed speaker, the box causes the apparent system Qts to increase by adding to the compliance of the suspension (air compliance of box + driver suspension). So when you put a driver in a box, especially one that is less than Vas in size, the system Q increases significantly. This is not the case with an open baffle. System Q remains about the same as the driver itself (its free air Qts) or may increase only very slightly. So, what does Qts describe? It describes the passband low frequency roll off "shape" for the driver. The lower the Qts, the more this roll of is slow and begins at a higher frequency. For the same Fs, lower Qts also means LESS SPL per watt of input power at Fs. This becomes a bit of a problem for an open baffle system, especially in your case where you want to operate a driver to 100Hz but want to use a narrow baffle. In this case both the baffle response and the driver response will be attenuating the SPL that is produced by the driver at 100Hz such that even when EQd and given the maximum rated input power you can not generate much SPL (compared to a boxed speaker). So, which SL likes low Q drivers for several reasons and they CAN be used in OB speakers, higher Qts (meaning Qts at least 0.5) helps you because more SPL can be generated by the driver at Fs in the open baffle. If you just experiment with some modeling of open baffle systems you will see this problem immediately.
Here I think you mean by "mms" millimeters. Do not use mms because Mms is the Thiele Small parameter for the mass of the diaphragm/coil, including acoustic load, so that is very confusing! Instead talk about Xmax, typically the distance the voice coil moves one way to give 10% reduction in motor strength.
The driver's excursion rating, Xmax, is also an important design variable and the needs are much different than for a boxed speaker. This is because the open baffle allows for the rear wave to cancel the front wave at lower frequencies. To achieve the same SPL (by EQing the driver) you have to apply more power, which will cause the cone to move more (more excursion). The SPL response falls at about 6dB/oct so you have to boost power at this rate to keep SPL constant at lower frequencies. This is a doubling of power each octave and excursion is going up along with power even though SPL remains the same. This is also a reason not to use drivers that have too low of a voltage sensitivity (low SPL/2.83V) because the power requirements can become very large quickly, especially with a narrow baffle and low frequency operation.
Larger driver with Qts>0.5 and above average Xmax can address most of the above points. Bonus if the driver also has high SPL/W and high Qts.
In a previous thread much like this one I mentioned to you a driver that is very good from 100Hz to 700Hz: the Peerless 830668 SLS. It has a good balance of all the properties that you need for an open baffle driver operating in this frequency band. I would not use a narrow baffle for this driver but use one that is about 0.5m wide. Use a narrow baffle or no baffle for the higher frequency drivers, above 700Hz.
There are surely other drivers that would work as well as this one or better. You should first understand the tradeoffs and how to model the response that you will get when you mount a driver in an open baffle. Then you can start to do some modeling yourself and come to your own conclusion about which to choose.
Thank you a lot Charlie to took the time to answer to my many questions.
Yes, my bad, you understood : i talked about Xmax (mms is a wrong term) !
My first question was badly writed, I meaned : no Bafle at all.
If the driver is carrefully choosed for a band like the 100 (<200) to 700 hz with a higher + 6 DB or more in relation to the upper driver, does it mean less + EQ ( à la linkwitz transform) but just allow - EQ to correct the peaks and avoid the distorsion than a positive EQ give ?
I my head, i would like just a driver for the difficult mid-bass (in all the designs it's a difficult task according to me); around 700 hz because the roll off of the bare driver under 600 if no load seems to me a good idea... in theory ! I was thinking to the 22 EX Seas magnesium cone, which distorsion is good below 900 hz but fears for a lack of SPL to avoid distorsions in a normal living room because of the positive EQ and the high slope to hidden the peak for the upper driver !
Is there a free soft for simulation ? EasySound is a liitle expensive to learn or to play with a standalone design... at least for me ?
Longer voice coil is equal to more dynamic but less micro details (more time for the cone to come back with small signals... I think about voices e.g.)
More excursion with greater Xmax : so my understanding is SPL of a given driver is measured at Xmax. It means less fast and transcient because longer excursion and longer voice coil...
So here a greater BL doesn't help for fastness and transcient in relation to the signal because the distance stay longer but the BL helps for stopping the cone easylier? Is my understanding correct or in the reality, ears can't hear the difference (transcient & impacts would be given by a good tweeter and the dryness given by the lack of box in an OB design?). In two words a better trade off than a dynamic closed or vented box because the global clearness stays better ?
Thank you for the reference about the driver, it helps a lot to understand and it's concrete !
I liked the Juhazi work with him Aino's speakers and would start myself a longterm project (need more to learn theory by now) inspired with it and try to match a limited mid-bass and a planar or a horn above. So an active four ways like that
-closed box to 35 hz to 100 (<200 max)
- OB mid bass 700 hz (< 1000) choice in relation to the minimum EQ in the + spl (no problem to cut because no distorsion but problem to add spl because more distorsion and higher move of the cone)
- Planar à la B&G Neo (AMT is too much fast in relation to the lower mid-bass)
- tweeter for more than 6 000 hz.
So all those wishes are theory ! In my mind my targett would be to have a good tonal balance because (I'm very sensible to it) and more dynamics than my 85 db speaker (which has a subjective fastness & punch but a lack of dynamic ) with avoiding old JBL speakers defaults !
My understanding is a CD with horn stay problematic to match with a classic driver if starting ater 700 hz (mismatch of fastness & dynamic) and have also problem of directivity (sound seem throwed in relation to the overs drivers)....
Yes, my bad, you understood : i talked about Xmax (mms is a wrong term) !
My first question was badly writed, I meaned : no Bafle at all.
If the driver is carrefully choosed for a band like the 100 (<200) to 700 hz with a higher + 6 DB or more in relation to the upper driver, does it mean less + EQ ( à la linkwitz transform) but just allow - EQ to correct the peaks and avoid the distorsion than a positive EQ give ?
I my head, i would like just a driver for the difficult mid-bass (in all the designs it's a difficult task according to me); around 700 hz because the roll off of the bare driver under 600 if no load seems to me a good idea... in theory ! I was thinking to the 22 EX Seas magnesium cone, which distorsion is good below 900 hz but fears for a lack of SPL to avoid distorsions in a normal living room because of the positive EQ and the high slope to hidden the peak for the upper driver !
Is there a free soft for simulation ? EasySound is a liitle expensive to learn or to play with a standalone design... at least for me ?
Longer voice coil is equal to more dynamic but less micro details (more time for the cone to come back with small signals... I think about voices e.g.)
More excursion with greater Xmax : so my understanding is SPL of a given driver is measured at Xmax. It means less fast and transcient because longer excursion and longer voice coil...
So here a greater BL doesn't help for fastness and transcient in relation to the signal because the distance stay longer but the BL helps for stopping the cone easylier? Is my understanding correct or in the reality, ears can't hear the difference (transcient & impacts would be given by a good tweeter and the dryness given by the lack of box in an OB design?). In two words a better trade off than a dynamic closed or vented box because the global clearness stays better ?
Thank you for the reference about the driver, it helps a lot to understand and it's concrete !
I liked the Juhazi work with him Aino's speakers and would start myself a longterm project (need more to learn theory by now) inspired with it and try to match a limited mid-bass and a planar or a horn above. So an active four ways like that
-closed box to 35 hz to 100 (<200 max)
- OB mid bass 700 hz (< 1000) choice in relation to the minimum EQ in the + spl (no problem to cut because no distorsion but problem to add spl because more distorsion and higher move of the cone)
- Planar à la B&G Neo (AMT is too much fast in relation to the lower mid-bass)
- tweeter for more than 6 000 hz.
So all those wishes are theory ! In my mind my targett would be to have a good tonal balance because (I'm very sensible to it) and more dynamics than my 85 db speaker (which has a subjective fastness & punch but a lack of dynamic ) with avoiding old JBL speakers defaults !
My understanding is a CD with horn stay problematic to match with a classic driver if starting ater 700 hz (mismatch of fastness & dynamic) and have also problem of directivity (sound seem throwed in relation to the overs drivers)....
Free Software:
software
Learn how to model a driver in an open baffle and you will be able to answer many of these questions yourself. That is where you should start.
A good choice for software for this would be:
Woofer Box and Circuit Designer
Baffle Diffraction and Boundary Simulator
The first one is doing the simulation of the driver in an infinite baffle. Set Vb = 99999 liters. The second one can simulate the baffle response of the driver. If you are using the driver in free air this is less precise but you can approximate it as a square baffle equal to the driver frame diameter or a little less. Make sure to include the driver diameter in the simulation.
software
Learn how to model a driver in an open baffle and you will be able to answer many of these questions yourself. That is where you should start.
A good choice for software for this would be:
Woofer Box and Circuit Designer
Baffle Diffraction and Boundary Simulator
The first one is doing the simulation of the driver in an infinite baffle. Set Vb = 99999 liters. The second one can simulate the baffle response of the driver. If you are using the driver in free air this is less precise but you can approximate it as a square baffle equal to the driver frame diameter or a little less. Make sure to include the driver diameter in the simulation.
One important question - are you going to use dsp for xo or passive? Passive design is way beyond my knowhow! With dsp (eg. Minidsp 4x10Hd) we can overcome many difficult issues with equalizing, sensitivities and delays.
I think that a system like this is very difficult to simulate as a whole, trial and error is the way to go and dsp makes this possible too.
Peerless SLS12" is a good choise for dipole bass (above 100Hz) and relatively cheap too. It is widely used for dipoles and closed boxes. Pro drivers offer more sensitivity but are more expensive - B&C, Beyma, 18Sound...
Beyma 12MWNd (discontinued) response as without baffle, dipole. Notice 20dB difference in spl 100Hz - 800Hz!
I think that a system like this is very difficult to simulate as a whole, trial and error is the way to go and dsp makes this possible too.
Peerless SLS12" is a good choise for dipole bass (above 100Hz) and relatively cheap too. It is widely used for dipoles and closed boxes. Pro drivers offer more sensitivity but are more expensive - B&C, Beyma, 18Sound...
Beyma 12MWNd (discontinued) response as without baffle, dipole. Notice 20dB difference in spl 100Hz - 800Hz!
Attachments
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Satori is 6,5" wide. It can be equalized to 80Hz of course - but distortion at normal listening levels will be extremely high! Can you simulate cone displacement at 80Hz?
Linkwitz and Kreskowsky are using 8-10" midwoofers, or double 7" - and crossing them above 100Hz
This would be my choices of a dipole speaker well done
http://www.linkwitzlab.com/LX521/Description.htm
http://www.musicanddesign.com/NaO_NoteDetails.html
Linkwitz and Kreskowsky are using 8-10" midwoofers, or double 7" - and crossing them above 100Hz
This would be my choices of a dipole speaker well done
http://www.linkwitzlab.com/LX521/Description.htm
http://www.musicanddesign.com/NaO_NoteDetails.html
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Hi Juhazi,
Thank you for the hints,
Yes of course active (I hope better digital active products than the MiniDSPs of todays to go more with digital EQ but with true 75 ohms links), I believe it's impossible without that tools for an enthusiast ! But the prices get lower and lower...)
One difficulty for me is to understand how much more SPL is needed for this mid bass for EQ compensation in relation to the next driver : it would be like you a Neo 8 family or any driver who allow to cross around 5000 hz (to try to avoid the Munson-Fletcher bump here). According the few I understand it seems a non-sense to put a CD with horn above a bare bass-mid in OB arrangement ! What a pity, because a CD could be perfect after 800 hz. But I surmise both the fastness and the horn beaming to give more problems than solutions here... I see too much frenchs spend all their life with tunning their horn drivers with bad global coherence (even with Sota TAD cd...). I would like a planar but too expensive or uncertain with my diy skill ! And like the RD75 its height is un- (global cost could be good here because a two ways is possible).
About the choice of the mid-bass: because there are always never the maximum SPL at max Watt power on the datasheet but just the 1 watt spl sensibility : I can not know how loud this driver play at its Xmax ? PHL Audio are one of the rare brand which give the max SPL at max AES power (but they never give the fhz curves !)
E.g. : if my mid bass is given for 90 db : do I need just +6 to + 9 db more than the upper mid to align the outputs of both drivers. The idea will be to do like you did : i assume you didn't need too much positive EQ but more negative EQ on the Beyma to plane the peaks (than to raise deeps with positive EQ above the given 1 w / xx spl) ? Avoiding positive EQ to avoid both too long excursion (= lake of dynamic & transcient in theory) & hearable distorsions would be the goal ?
I saw Seas Prestige 26REX4 also which seem good with 90 db and Xmax equal to the Peereless SLS. PHL 3020 with 96 db (but with 5.5 Xmax) output 116 DB at max AES power (200 W). Both have poor QTS but I saw with your design it could be a better trade off : more EQ but better transcient so professional driver only or high QTS (min 0.5) like the SLS ? The 26 W magnesium cone could be interesting because the good distorsion below 800 hz and a good Xmax but very expensive (too much) and a resonance to padlle with a four order slope minimum.
There is not too much choice in fact when you want a so low XO in OB with a 10": Beyma, maybe one Faital, PHL for the pros, maybe EMS speaker (very impressive low QTS but poor Xmax and a lack of measurement in their site). All the others I saw can not be crossed below 200 àr 250 without box because they beginn to fall at those values.
Working with high efficienty is also a motivation to go after with little DIY class A amps à la Nemesis for the mid bass and upper drivers ! if I am a lover of closed box for the bass, what Troels said about him OBL-11 is interresting : why not a 15" driver below the 150 hz, but laterally beaming inside (between the speakers) in an OB arrengement ? I can not hear problem of directivity with my actual 125 hz XO : the bass is a band pass beaming behind the speaker at 80 cm of the front wall ! (1 meter for the side walls)...
I need to do a documentation work as it is an ambitious project for me...Not easy to do better than a good commercial speaker, I would try more to make different in fact with trying OB after a closed sub. I'm not hurry as it's a lot of money for me : i see it more as a long term hobby here. Challenging a 125 hz to 2600 hz aluminium 5" mid maid by Phill Johns and inspired of its AE1 speaker is an impossible task for a first enthusiast design... even with the all the DSP. The DSP give not me the knowledge. So I need to read more (always read all the Linkwitz & Nao) and of course play with softs as Charlie said. A high learning curve to targett which is attractive for me. Not hurry, I would to understand much more than today before a go/no-go . Sorry to be tso long...
Thank you for the hints,
Yes of course active (I hope better digital active products than the MiniDSPs of todays to go more with digital EQ but with true 75 ohms links), I believe it's impossible without that tools for an enthusiast ! But the prices get lower and lower...)
One difficulty for me is to understand how much more SPL is needed for this mid bass for EQ compensation in relation to the next driver : it would be like you a Neo 8 family or any driver who allow to cross around 5000 hz (to try to avoid the Munson-Fletcher bump here). According the few I understand it seems a non-sense to put a CD with horn above a bare bass-mid in OB arrangement ! What a pity, because a CD could be perfect after 800 hz. But I surmise both the fastness and the horn beaming to give more problems than solutions here... I see too much frenchs spend all their life with tunning their horn drivers with bad global coherence (even with Sota TAD cd...). I would like a planar but too expensive or uncertain with my diy skill ! And like the RD75 its height is un- (global cost could be good here because a two ways is possible).
About the choice of the mid-bass: because there are always never the maximum SPL at max Watt power on the datasheet but just the 1 watt spl sensibility : I can not know how loud this driver play at its Xmax ? PHL Audio are one of the rare brand which give the max SPL at max AES power (but they never give the fhz curves !)
E.g. : if my mid bass is given for 90 db : do I need just +6 to + 9 db more than the upper mid to align the outputs of both drivers. The idea will be to do like you did : i assume you didn't need too much positive EQ but more negative EQ on the Beyma to plane the peaks (than to raise deeps with positive EQ above the given 1 w / xx spl) ? Avoiding positive EQ to avoid both too long excursion (= lake of dynamic & transcient in theory) & hearable distorsions would be the goal ?
I saw Seas Prestige 26REX4 also which seem good with 90 db and Xmax equal to the Peereless SLS. PHL 3020 with 96 db (but with 5.5 Xmax) output 116 DB at max AES power (200 W). Both have poor QTS but I saw with your design it could be a better trade off : more EQ but better transcient so professional driver only or high QTS (min 0.5) like the SLS ? The 26 W magnesium cone could be interesting because the good distorsion below 800 hz and a good Xmax but very expensive (too much) and a resonance to padlle with a four order slope minimum.
There is not too much choice in fact when you want a so low XO in OB with a 10": Beyma, maybe one Faital, PHL for the pros, maybe EMS speaker (very impressive low QTS but poor Xmax and a lack of measurement in their site). All the others I saw can not be crossed below 200 àr 250 without box because they beginn to fall at those values.
Working with high efficienty is also a motivation to go after with little DIY class A amps à la Nemesis for the mid bass and upper drivers ! if I am a lover of closed box for the bass, what Troels said about him OBL-11 is interresting : why not a 15" driver below the 150 hz, but laterally beaming inside (between the speakers) in an OB arrengement ? I can not hear problem of directivity with my actual 125 hz XO : the bass is a band pass beaming behind the speaker at 80 cm of the front wall ! (1 meter for the side walls)...
I need to do a documentation work as it is an ambitious project for me...Not easy to do better than a good commercial speaker, I would try more to make different in fact with trying OB after a closed sub. I'm not hurry as it's a lot of money for me : i see it more as a long term hobby here. Challenging a 125 hz to 2600 hz aluminium 5" mid maid by Phill Johns and inspired of its AE1 speaker is an impossible task for a first enthusiast design... even with the all the DSP. The DSP give not me the knowledge. So I need to read more (always read all the Linkwitz & Nao) and of course play with softs as Charlie said. A high learning curve to targett which is attractive for me. Not hurry, I would to understand much more than today before a go/no-go . Sorry to be tso long...
Uh, have you looked at Xmax limited SPL at 80Hz for that driver in an open baffle? Its a very bad choice!
Maybe a question to beginn with : is it possible to calcul the maximum SPL output of a driver with the Small&Thiel datas ? BL ; sensibility at 2.83 v ; Xmax + 10% and Max Watt ?
Thanks Juhazi, you gave a lot with your Aino speaker "serie". From what you showed above and the Neo 8, my understanding is your EQ around + 3 db the Beyma in the low and lowered the high mid to match with the Neo; this one was bumped in its low end with someting near 6 db... just with noise without look at again your pdf...
Loking at the Nao Note a 8" seems enough for the low mid (withe the RS not sure 2x 6" is better for some reasons... or if a Xo like the Kef 104/ref : the two mids are not really symetric in their XO... but it seems to be the flag ship of the both !).
Why Juhazi did you choose a 12" ? just for the Sd ? IIRC youur XO is not so low with the bass box, more around 200 to 300...
Thanks Juhazi, you gave a lot with your Aino speaker "serie"
. From what you showed above and the Neo 8, my understanding is your EQ around + 3 db the Beyma in the low and lowered the high mid to match with the Neo; this one was bumped in its low end with someting near 6 db... just with noise without look at again your pdf...Loking at the Nao Note a 8" seems enough for the low mid (withe the RS not sure 2x 6" is better for some reasons... or if a Xo like the Kef 104/ref : the two mids are not really symetric in their XO... but it seems to be the flag ship of the both !).
Why Juhazi did you choose a 12" ? just for the Sd ? IIRC youur XO is not so low with the bass box, more around 200 to 300...
Gradient 1. has a 12" nude mid - that was my inspiration and guideline. I even thought of a 15" but the price goes up considerably. I chose a pro driver because of high efficiency. I chose Beyma 12MWND because of it's low distortion and smooth response, high efficiency and power rating - I was actually thinking I could drive it up to 1,5kHz or something like that, and use LR2 xo. And it looks sexy! It does not have super extension capability but Qts is reasonable. I don't believe it was the best choice but now I walk with it!
http://www.lautsprechershop.de/pdf/beyma/beyma_12mwnd.pdf
With minidsp I attenuate in the passband (some -12dB for dipole loss) and boost only below hp xo (around 130-180Hz depending on config version) max some 6dB at 50Hz. I aim for LR4/elliptic acoustic xo. I hva tried LR2 but it stresses low end of dipole drivers too much - high distortion!
I also adjust level for each driver in minidsp. I also use a stronger amplifier for Beyma than Neo8 (Icepower 125ASX vs. 50ASX), spl at same input voltage is approximately 3dB higher with 125
So - "tour de force" approach, complex and ugly!
http://www.lautsprechershop.de/pdf/beyma/beyma_12mwnd.pdf
With minidsp I attenuate in the passband (some -12dB for dipole loss) and boost only below hp xo (around 130-180Hz depending on config version) max some 6dB at 50Hz. I aim for LR4/elliptic acoustic xo. I hva tried LR2 but it stresses low end of dipole drivers too much - high distortion!
I also adjust level for each driver in minidsp. I also use a stronger amplifier for Beyma than Neo8 (Icepower 125ASX vs. 50ASX), spl at same input voltage is approximately 3dB higher with 125
So - "tour de force" approach, complex and ugly!
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I remember look design was one of your major concern also. yes it looks fine...
Professional driver is a good choice in an OB desoign if my understanding is correct because of the non linear suspension of the cone. Linear suspension is not a good choice according to me in OB with the classic driver because with the longer excursion peripherical suspensions needs to be harder when the exursion grows which allow such drivers.
Did you try to put your 12" on the floor in front of the bass cabinet and beaming towards the listening position to have +3 to + 6db ? A design à la OBL11 is tempting not with bass (because closed cabinet) but with the 12" mid-bass. Or to go like the Gradiant 1 with a little load around the driver like a circular ob frame ?
I'm looking at this one : PHL 3420... but maybe to Low Xmax with 5.5 mm and efficienty with 96 db only ! Welcome on PHL audio web site
Professional driver is a good choice in an OB desoign if my understanding is correct because of the non linear suspension of the cone. Linear suspension is not a good choice according to me in OB with the classic driver because with the longer excursion peripherical suspensions needs to be harder when the exursion grows which allow such drivers.
Did you try to put your 12" on the floor in front of the bass cabinet and beaming towards the listening position to have +3 to + 6db ? A design à la OBL11 is tempting not with bass (because closed cabinet) but with the 12" mid-bass. Or to go like the Gradiant 1 with a little load around the driver like a circular ob frame ?
I'm looking at this one : PHL 3420... but maybe to Low Xmax with 5.5 mm and efficienty with 96 db only ! Welcome on PHL audio web site
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