Just after some advice as I want to try to use an 8 inch woofer in a sealed design with a maximum internal size of 25L. Using something like the Peerless P835026 gives me a QTC of 0.824. Can someone advise me of the disadvantages of not hitting the 0.7 mark and if its detrimental to mix paper and aluminium cones in one design. I think it would be.
Thanks.
Thanks.
QTC - has got to be the biggest internet audio myth. Model for the flatest response before roll-off and forget QTC. A QTC of 0.7 often sounds thin because it most cases it rolls off early and you lose midbass.
Once you've heard how incridibly tight the bass sounds with a speaker like the JPW AP2 (Q of around 1.2), you realise that Q has nothing to do with speed and it's only the frequency response that subjectively makes the bass sound slow, boomy or thin.
Once you've heard how incridibly tight the bass sounds with a speaker like the JPW AP2 (Q of around 1.2), you realise that Q has nothing to do with speed and it's only the frequency response that subjectively makes the bass sound slow, boomy or thin.
...same with paper/alu cones. Keep paper/metal cones in control with cross over/DSP and you'll be fine...
Thanks for the replies. Any suggestions around a good 8 inch woofer for a sealed enclosure of around 25l would be appreciated. 87db and above preferred.
Qtc is not a myth, it is very real. The flattest response before roll-of is Qtc=0.707 and also with the lowest possible -3 dB point.
A Qtc lower than 0.7 may sound thin, because it rolls of earlier than Qtc=0.707 (it has higher -3 dB point) and may lose midbass.
Qtc determines the frequency response in the low end, so it is the Qtc who makes the bass sound boomy or thin.
Sorry, bad wording on my part. I should have said "the myth surrounding QTC"
I still stand by what I said. Ignore QTC and model for the frequency response you want. Some of the best sounding commercial designs have a higher QTC that 0.7 for a good reason - AR7, AR8, JPW AP 1/2/3, Snell K, Heybrook HB1 etc all have a QTC of 1 or above.
I still stand by what I said. Ignore QTC and model for the frequency response you want. Some of the best sounding commercial designs have a higher QTC that 0.7 for a good reason - AR7, AR8, JPW AP 1/2/3, Snell K, Heybrook HB1 etc all have a QTC of 1 or above.
Qtc around 1-1.2 may work around 80-100 hz but you will most likely be frustrated if you tune them so below 70 hz, in a domestic room you will end up with a one not bass that is tiring in the long run
Yes, and that's exactly why I suggest modeling the low frequency response, rather than choosing a particular QTC.
Another problem can be running out of xmax when you put your driver in a bigger box to lower QTC (Stuffing can lower QTC but doesn't affect xmax).
If it's for a 2-way, then something with a smooth roll-off would make life easier. The Seas CA22NRX looks good on paper.
Peerless P835026 with Qtc around 0.8 is just fine - almost the lowest possible F3 (-3 dB), not so big enclosure volume and very good bass sound quality.
And that is exactly why driver which can hit lower than 60 Hz (such as Peerless P835026) should be modeled by choosing a particular Qtc.
Not sure if it's a language barrier thing or i'm not explaining it properly. Perhaps i'll upload some graphs when I have time.
It does look good on paper. I will put this into winisd and see what I can do with it. Thanks for the suggestion.
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