chicken and egg situation for me here i think. i was going to make the amp in accordance to what i needed it to do for the driver + box combo. wrong way around?
also add in another question,
is that VAS likely to be correct? its seriously low compared to the others and with it that low half the attempts at BiB's or others get an utterly horrible response to them.
i can't do the closed box test, so can anyone suggest alternative ways to double check this. will adding more mass increase accuracy or shall i just try it regardless?
is that VAS likely to be correct? its seriously low compared to the others and with it that low half the attempts at BiB's or others get an utterly horrible response to them.
i can't do the closed box test, so can anyone suggest alternative ways to double check this. will adding more mass increase accuracy or shall i just try it regardless?
adding extra mass did nothing to the VAS numbers, i'll just have to assume this is accurate, unless increasing the ambient temperature above what it is now would likely cause significant changes? this room is likely 5 or so degrees colder than the room where these would be used.
from my understanding, the VAS is related to the suspension, as is the CMS. so either these are wrong by measurement, or the suspension of these loudspeakers is far less than that of the guide sound/AN units i mentioned previously? is this likely to cause me problems with cone excursion? the electrical side of this stuff really doesn't agree with me, so i apologise for ignorance again. i think i read somewhere that it would also cause quite a 'thin' sound?
thanks again.
from my understanding, the VAS is related to the suspension, as is the CMS. so either these are wrong by measurement, or the suspension of these loudspeakers is far less than that of the guide sound/AN units i mentioned previously? is this likely to cause me problems with cone excursion? the electrical side of this stuff really doesn't agree with me, so i apologise for ignorance again. i think i read somewhere that it would also cause quite a 'thin' sound?
thanks again.
An externally hosted image should be here but it was not working when we last tested it.
Normally, but you could do it your way, i.e. design based on 'x' amount of output impedance, then build either an amp with this amount or better yet, one with a variable DF.
GM
Vas is a function of Fs, Sd, Cms, Mms, po, c, so assuming the posted values are based on the effects of the added mass, then mathematically calculating it yields virtually the same specs you measured with the fractional difference probably due to me using a different po, c value than the measuring program.
From the early books I learned from, one uses the closed box way and find where Fs is ideally raised 1.56x to make it easy/accurate to calculate a theoretically ‘ideal’ net Vb, or the Vas spec after T/S design theory became popular.
In a somewhat more recent book by Ray Alden though, adding mass to lower Fs by at least 25% is recommended and what just about everybody uses these days. From this it seems reasonable to me that increasing mass beyond what's required to lower Fs by 25-64% won’t increase accuracy.
GM
What other shapes work better? Would a longer phase plug of the same shape be better?
Thanks,
Deon
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.