Great info, thanks! So the answer is, there really are woofers available that start at 105+ db efficiency, that can also play to 40hz. Only a small handful, or do manufacturers have them made that way? I've not ran across many/any woofers THAT efficient in my looking around. The Faital Pro 15pr400 is supposed to be 99db efficient. I thought that was high.
As far as my Kappalites ... they are amazing. One alone will run you out of a room. They only play happily to about 400hz though. But I have them in 2.8cu ft each. I just can't be okay with 6cu ft bass cabinets, to use two of them. Just TOO big. Yes, I want efficiency. But the Forte has 99db efficiency with a single woofer and a passive. I'm trying to figure out how they do that exactly. Just trying to learn, my way.
I may not reply to everything ... But I research the hell out of what you guys post! Thank you again. This thread may be stupid to the experienced designers/builders ... but it has been great for me.
As far as my Kappalites ... they are amazing. One alone will run you out of a room. They only play happily to about 400hz though. But I have them in 2.8cu ft each. I just can't be okay with 6cu ft bass cabinets, to use two of them. Just TOO big. Yes, I want efficiency. But the Forte has 99db efficiency with a single woofer and a passive. I'm trying to figure out how they do that exactly. Just trying to learn, my way.
I may not reply to everything ... But I research the hell out of what you guys post! Thank you again. This thread may be stupid to the experienced designers/builders ... but it has been great for me.
Funny you say this ... I have never heard a high end coaxial in large format. Just some older KEFs. I wonder why you don't see more of them?
Isnt that nearly a majority? Look at how they're wrapped around the axle of "a compound OB sub gives 6db..." The guy measured it, the math shows it - still gotta talk it to death. I think I'll head over and add my 2 cents!
This is a classic dilemma (Hofmann's Iron Law, see below) with low frequency loudspeakers:
1. frequency extension
2. small size
3. high efficiency
Choose two of these, throw away one, there is no other option yet, physics don't lie.
Josef Anton Hofmann - Wikipedia
Klipsch often claims in-room efficiency of their loudspeakers, where the usual boost from reflections considered in. Other manufacturers doesn't really use that method and that's why Klipsch sensitivity/efficiency numbers are unusual high. Below are the measurements. The full-space efficiency probably even lower, because Stereophile uses nearfield technique to measure low frequency response, so the baffle step loss doesn't show up in this way.
Klipsch Forte III loudspeaker Measurements | Stereophile.com
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Others said so already, but the Calpamos seems to tick a lot of boxes, using the Faital 15.
http://www.humblehomemadehifi.com/download/Humble Homemade Hifi_Calpamos.pdf
Very good documentation for a completed design.
You could reuse your kappalites in another system, or build 4 distributed subs, Geddes style. Lots of woodworking.
http://www.humblehomemadehifi.com/download/Humble Homemade Hifi_Calpamos.pdf
Very good documentation for a completed design.
You could reuse your kappalites in another system, or build 4 distributed subs, Geddes style. Lots of woodworking.
The talk about sensitivity of woofer versus system system is sort of misleading. Woofer sensitivity is the bottom line...system sensitivity is just what happens after voicing...end of story, and not particularly important to sound quality.
With that being said, more important is efficiency, not to be confused with sensitivity. Efficiency is the difference between power given and excursion received...sensitivity is the difference between power given and spl received...There isn't very much variance in spl vs excursion of any driver unless a vented design is involved. Long story short....higher efficiency, the lower the excursion, regardless of power sensitivity... Period... lower excursion, lower efficiency.
If I have a large woofer that equates to high efficiency, I might end up with a 88db sensitivity due to voicing choices or gain matching of other driver...the efficiency still remains, and is evident in the resulting excursion...
If I have a high sensitivity driver with lower efficiency....I am just going to reach higher excursions with less power...nothing to be happy about per say.
Higher woofer sensitivity allows for less power to be used which sonically is a benefit by lower heat in the voice coil. I think also, its evident that a higher driver sensitivity is a tell that a woofers diaphragm is ready to move quickly as well so there is likely a sonic benefit there, admittedly, though the same is not true for a variance in system sensitivity...If you raise the gain somewhere in the gain structure of dsp, you automatically have a higher system sensitivity....but efficiency has not changed nor woofer sensitivity, so who cares.
Larger woofers are more efficient, regardless of sensitivity, it seems, in most cases....end of story. Efficiency means more signal is being turned into sound, and not into distortion or heat....No need to argue why that is a good thing for your playback
If this resonance issue you speak of does not result in a longer decay somewhere in the bandwidth....who cares. "Resonance problems" is vague to me at this point since all sound is a resonance you have not made a point. High sensitivity and high efficiency are not the same but more importantly its a matter of excursion vs spl first and foremost.
Someone said that high sensitivity drivers have no bass extension....correction.....high sensitivity drivers have no natural bass extension....Fs is only important if group delay gets to crazy after adding extension with eq. Fs is irrelevant if using a vented design. Bass extension is truly defined by power ability and Xmax. Thats it.
With that being said, more important is efficiency, not to be confused with sensitivity. Efficiency is the difference between power given and excursion received...sensitivity is the difference between power given and spl received...There isn't very much variance in spl vs excursion of any driver unless a vented design is involved. Long story short....higher efficiency, the lower the excursion, regardless of power sensitivity... Period... lower excursion, lower efficiency.
If I have a large woofer that equates to high efficiency, I might end up with a 88db sensitivity due to voicing choices or gain matching of other driver...the efficiency still remains, and is evident in the resulting excursion...
If I have a high sensitivity driver with lower efficiency....I am just going to reach higher excursions with less power...nothing to be happy about per say.
Higher woofer sensitivity allows for less power to be used which sonically is a benefit by lower heat in the voice coil. I think also, its evident that a higher driver sensitivity is a tell that a woofers diaphragm is ready to move quickly as well so there is likely a sonic benefit there, admittedly, though the same is not true for a variance in system sensitivity...If you raise the gain somewhere in the gain structure of dsp, you automatically have a higher system sensitivity....but efficiency has not changed nor woofer sensitivity, so who cares.
Larger woofers are more efficient, regardless of sensitivity, it seems, in most cases....end of story. Efficiency means more signal is being turned into sound, and not into distortion or heat....No need to argue why that is a good thing for your playback
If this resonance issue you speak of does not result in a longer decay somewhere in the bandwidth....who cares. "Resonance problems" is vague to me at this point since all sound is a resonance you have not made a point. High sensitivity and high efficiency are not the same but more importantly its a matter of excursion vs spl first and foremost.
Someone said that high sensitivity drivers have no bass extension....correction.....high sensitivity drivers have no natural bass extension....Fs is only important if group delay gets to crazy after adding extension with eq. Fs is irrelevant if using a vented design. Bass extension is truly defined by power ability and Xmax. Thats it.
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The 15pr400 is not 99db efficient and the pair I had deviated from each other more than others I had that were comparable (GPA 5168B)
Think of resonance as cone breakup. Are you denying the need to regulate that behavior of any transducer? Do you figure what cone breakup does with your ‘efficiency’?
It’s not Xmax. It’s Vd. And group delay isn’t some physical magnitude that could not be altered. It’s the outcome of filter functions that can be changed and isn’t even that relevant in home or pro audio.
The benefit of DSP is numerous, but the sience is the same as for the passive filter, and can be even more complex with FIR filters. DSP is more convenient since you dont have to solder and have several coils and capacitors for the testing.
Im not going to argue about group delay...I already proved its validity in my thread...the group delay curve and the time to peak energy are analogous...you are just one rew measurement away from enlightenment
Break up, you may have something to teach me there...but whos playing a cone into breakup anyway.
Vd is a derivative of xmax, so sure...
Vd is not a derivative. And I’d like to be enlightened about the perception of the human hearing wrt group delay of low frequencies in normal listening rooms. We can measure a lot. Hope you read the other thread about Hilbert transformations and phase issues here . 
On cone breakup, I designed some systems with cone breakup outside passband. Funny thing is I ended up with relatively small drivers. Please show me the 15” that does 98dB/2,83V and 1kHz without breakup.
On cone breakup, I designed some systems with cone breakup outside passband. Funny thing is I ended up with relatively small drivers. Please show me the 15” that does 98dB/2,83V and 1kHz without breakup.
Beyma 15mi100 and v2 seems good candidates too.
But i would say with middly annoying breakup rather than without breakup.
Camplo could you point to time to peak energy/ gd curves in your thread please i missed that.
Markbakk's comment about the room is still valid: don't forget that in the couple room/loudspeakers below Schroeder freq room dominate. Only way to compensate this is either acoustic treatments either dsp ( fir used as DRC even if i think you correct the loudspeakers more than the room hence i dislike the name) either both.
Flaxxer,
Dsp/passive is not really different and the science is equally important in both approach.
From my own experience: passive imply interactions which you need to master. I' am not patient enough to master them without loosing the poor last hairs i've still got.
The cost to prototype if you don't already have a stock of components increase fast and even then you'll have to validate with definitive components which add costs even more ( even if you stay within 'standard' quality components).
Dsp can seems costly at first but once you have good gear there is no need to change it regularly. There is some very nice sounding solution existing even for moderate costs ( even cheap if one can accept some limitations).
The real drawback in my view is in the ergonomy of the system and the space ( even if small can be made).
The real thing is you need to measure. And the results will depends a lot on the quality of measurements. Same thing is true for passive but i think it is even more true for a dsp approach as you can perform a lot more things ( bad or good) than with passive.
So if like me you choose to go dsp route be prepared to take measurements, learn how to interpret them, etc,etc,...
And before spending on anything i would invest in mic, stand, cables and soundcard and choose a software ( Arta, Rew,..) and learn how to use it whatever the approach.
But i would say with middly annoying breakup rather than without breakup.
Camplo could you point to time to peak energy/ gd curves in your thread please i missed that.
Markbakk's comment about the room is still valid: don't forget that in the couple room/loudspeakers below Schroeder freq room dominate. Only way to compensate this is either acoustic treatments either dsp ( fir used as DRC even if i think you correct the loudspeakers more than the room hence i dislike the name) either both.
Flaxxer,
Dsp/passive is not really different and the science is equally important in both approach.
From my own experience: passive imply interactions which you need to master. I' am not patient enough to master them without loosing the poor last hairs i've still got.
The cost to prototype if you don't already have a stock of components increase fast and even then you'll have to validate with definitive components which add costs even more ( even if you stay within 'standard' quality components).
Dsp can seems costly at first but once you have good gear there is no need to change it regularly. There is some very nice sounding solution existing even for moderate costs ( even cheap if one can accept some limitations).
The real drawback in my view is in the ergonomy of the system and the space ( even if small can be made).
The real thing is you need to measure. And the results will depends a lot on the quality of measurements. Same thing is true for passive but i think it is even more true for a dsp approach as you can perform a lot more things ( bad or good) than with passive.
So if like me you choose to go dsp route be prepared to take measurements, learn how to interpret them, etc,etc,...
And before spending on anything i would invest in mic, stand, cables and soundcard and choose a software ( Arta, Rew,..) and learn how to use it whatever the approach.
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I would like to point out, once again, that the Kappalites are even less sensitive, per driver, than the bass drivers used in the OSMC.
If you find one Kappalite runs you out of the room, with regards to bass, then you should be fine with the OSMCs sensitivity wise.
Vd is not a derivative. And I’d like to be enlightened about the perception of the human hearing wrt group delay of low frequencies in normal listening rooms. We can measure a lot. Hope you read the other thread about Hilbert transformations and phase issues here .
On cone breakup, I designed some systems with cone breakup outside passband. Funny thing is I ended up with relatively small drivers. Please show me the 15” that does 98dB/2,83V and 1kHz without breakup.
Derivative =2 : having parts that originate from another source
Vd = This parameter is the Peak Diaphragm Displacement Volume — in other words the volume of air the cone will move. It is calculated by multipying Xmax (Voice Coil Overhang of the driver) by Sd (Surface area of the cone). Vd is noted in cc.
Well, I never intended for my 15" to ever play that high but they say Acoustic Elegance drivers can??? Please show me a good reason to run a 15" past 8-900 since we normally do not run a driver into beaming territory
Down below, the room dominates is what you are saying...but does it really? Isnt it all a matter of what your direct sound to room sound ratio maybe? Time to peak energy is a no brainer...if the signal lags (too far) behind the rest of the signal, its not desirable.
Is there a specific link to that information you spoke of?
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