I guess what I want to know is how much delay is needed for it to be noticeable or to have a negative effect. Right now the subwoofer I am using shows a group delay peak at 20hz of 120ms and I don't notice any undesireable effect. Isn't it the delay at the crossover frequency that is most critical? Or am I mistaken?
One other side note, the Xmax of the 2" driver is listed as 1mm the actual mechanical limit of this driver is more like 3 to 4 mm, the one inch is listed as 1.95mm and also has the mechanical ability to move at least 3mm without any bottoming. Now I understand that the actual Xmax will determine the controlled movement but the mechanical limit is what must be considered when determining maximum volumes before popping or serious distortion ocurrs. When modeled at these numbers my designs exceed 120dbs every time so bass response is not a problem as long as you don't try to get silly about it. One of these drivers should have no problem hitting 80hz provided it is properly loaded and has a steep order (at least 12db p.o.) high pass filter, and can do so at home theater volume levels. 4 of these drivers could very easily be made to put out excellent volume at 40hz, with a far cleaner signal and higher volume that an 8" full range driver I have modeled. I have 100s of models I have done on hornresp and I couldn't possibly share them all but if there is something someone would like to specifically see let me know and I will share it.
If I understand correctly (and I may not), group delay is generally not audible close to Fc, but more critical in the octave above Fc, less than 30ms seems to be the consensus. Again, if I understand right undesirable group delay results in a partial phase shift in the effected passband......much harder to account for in complex vented enclosures like horns where there is already delay present due to path length. Does hornresp account for the combined group+path length delay in the lower frequencies?
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You'll be in read-only mode for a few days.
i agree the horns look nice. i was merely suggesting that from what limited experimentation i have done, the group delay is grossly higher than a 'conventional' loudspeaker at similar frequencies.
What degree of audibility this presents is clearly debateable. some folks here will argue that in SOME cases delays of much less than the 6ms are audible, let alone 100ms or more.
from the dictionary definition of group delay, I would interpret it as being the time taken from initialistaion of signal input to output reproduction, verses/with respect to frequency. I envision this as the time taken for the EM force generated by the VC to overcome the diaphragm mass, hence why conventional loadings cause a higher group delay around resonance, and below. I am no expert, but i would think this is due to the loss of loading in each case. surely in the case of a horn, then, this would mean the horn is loaded 'optimally' for as much of the audio BW as possible, but that it is not loaded optimally for the driver Fs, and below.
i think this all shows that a horn is always a huge compromise, for fullrange. I totally agree that these drivers are interesting, and i will be using them---only higher up that 100hz---theyre not miraculous drivers after all
What degree of audibility this presents is clearly debateable. some folks here will argue that in SOME cases delays of much less than the 6ms are audible, let alone 100ms or more.
from the dictionary definition of group delay, I would interpret it as being the time taken from initialistaion of signal input to output reproduction, verses/with respect to frequency. I envision this as the time taken for the EM force generated by the VC to overcome the diaphragm mass, hence why conventional loadings cause a higher group delay around resonance, and below. I am no expert, but i would think this is due to the loss of loading in each case. surely in the case of a horn, then, this would mean the horn is loaded 'optimally' for as much of the audio BW as possible, but that it is not loaded optimally for the driver Fs, and below.
i think this all shows that a horn is always a huge compromise, for fullrange. I totally agree that these drivers are interesting, and i will be using them---only higher up that 100hz---theyre not miraculous drivers after all
the way i see it is: delay is delay. it matters when a harmonically rich sound has phase shifts caused by driver centre to centre spacing, depth offsets, crossovers, and loading alignment.
a group delay of even 100ms is 1/10th a second of transient delay or hangover, slurring the sound. 100ms is IMHO very obvious, when a well designed 12" sub like the visaton w3oo shows about 18ms peak group delay at 25hz, in a vented box, when simmed in WinISD.
The only real solid research i've seen places detectability at just over 5 uS (at 7k), results at lower frequencies seems mixed.
To have a smooth FR at the crossover between the rear loaded horn and the direct radiator component of a rear-loaded horn, the LF from the horn needs to be delayed by (2n+1)/2 (n = 0, 1, 2...) wavelengths at the crossover frequency. The longer the horn, the bigger the n.
The net result of this is that with any fundemental at a frequency below the XO, the harmonics (at least some of them) will arrive before the fundemental.
Some people seem mostly immune to this, some people it drives nuts.
dave
As horns are band -pass ,they can be a beautiful compromise
for the matter of the size , certainly above 100 Hz 
As horns are band -pass ,they can be a beautiful compromise
i totally agree! the front loaded horn i quickly modelled with the TB w2-800 for around 150-200 hz upwards seemed very good all be it a little large for some.
smaller horns could be made to satisy say 100-300hz upwards, with many of these small drivers. its only the group delay below the driver Fs which would concern me, if you stretch the passband a bit further into the 100's.
But I was thinking and referring to an ideal 6-8"😛
Everything would be scaled if a 1 or two inches cone would be used :
I wouldn't even bother to try and find out 🙄 As I said , the back wave doesn't count when such a speaker is put on the bottom of a frame -like in the Imac - and baffle-step seems the only predominant thing ...
Everything would be scaled if a 1 or two inches cone would be used :
I wouldn't even bother to try and find out 🙄 As I said , the back wave doesn't count when such a speaker is put on the bottom of a frame -like in the Imac - and baffle-step seems the only predominant thing ...
agreed. like most tvs are the same. using the tv casing as a baffle, nothing more than that.
For the Tang Band W1-1070SE ,Fs is about 200Hz so in normal conditions (voltage driven) band pass would start from that frequency .
But I do agree with Brsanko ...specially for the' They'll start to pop ' !!!!
The Pink horns with the 2" TBs play very loudly down to 100hz with no popping whatsoever, and require very little power. The 1" drivers model even better than the 2"ers. The only problem with the bookshelf speakers that my friend made was that they were tuned too low to play at a loud volume with just one driver, but they do perform exactly as modeled just like every other design we've built. Maybe I'm one of those people who isn't sensitive to delay, I don't know, I haven't noticed any of the effects mentioned but then my designs don't model with as much delay as others have quoted either.
Define "done successfully"! Modelled check, attached gospel from another build with a different driver to this check......... built, measured, pics, etc. no. That's the caveat for me here....without a build and measurements this thread is useless IMO. Here's an analogy: I could get on any racing forum and state that my KIA powered ferrari runs a 10 second 1/4 mile, but without some form of proof it's just hot air- get the picture? It doesn't matter what beautiful horn enclosure you put around this driver, it's never going to produce what it's not physically capable of. Don't be mad at us for the stigma YOU put on this thread sir. If you had not accounted for some skepticism when you started the thread, that's your oversight. I will await graphs.
If thread is useless why do you keep reading it and responding to it? Do not read my posts please I am not interested in anything you have to say. I am not here to impress you I am here to share knowledge I have. if you had engine simulation software that you have used successfully in the past and you had simulated modifications to your KIA engine and the simulations showed unbelievable results that were consistant with previous results and the software had always been perfectly acurate in the past, I would be very excited about your KIA. You go tell David McBean that his software is nothing but hot air and then when he agrees with you have him suggest I stop using it and putting faith in it's pedictions. Until then DO NOT READ MY POSTS!!!!!!!!!!!!!!!
BTW I can almost certainly guaranty that you could sufficently modify a KIA engine to launch a Ferrari to a 10 sec quarter mile for far less money than it would cost to buy a new Ferrari engine. So stick you naysaying and ridiculous skepticism where it belongs
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