I know that horn loading requires a low Qts and reflex cabinets like a Qts of 0.35 for optimum flat response. What's the optimum driver Qts for sealed boxes? Thanks, best regards Moray James.
I would have to think it depends on your definition of optimum. Also wouldn't the "optimum" Qts depend on Fs? Sorry no answers from me, only more questions😱
Joe
Joe
Recommended sealed Qts is usually 0.4 and above, though Qtc (0.5-1.2) determines
response. Recommended ported Qts is usually 0.5 and below.
response. Recommended ported Qts is usually 0.5 and below.
Of course not🙂 but due to infinite variable T/S specs of drivers and endless tastes in the finished response of immeasurable people, it can get quite high. I have used drivers with 0.75 - 0.85 Qts and they are a pain to get good response out of in my chosen boxes.
They (various sites I've seen) reckon between 0.4 and 0.7.
Higher, it's only really useful for IB or OB applications, the output peak around resonance would be too much for a sealed box, it'd need to be mahoosive.
Lower Qts will give an earlier roll off, but a smaller box. Higher will get flat response closer to Fs, but needs a bigger box to do so. Take your pick - it's all compromises.
Chris
Higher, it's only really useful for IB or OB applications, the output peak around resonance would be too much for a sealed box, it'd need to be mahoosive.
Lower Qts will give an earlier roll off, but a smaller box. Higher will get flat response closer to Fs, but needs a bigger box to do so. Take your pick - it's all compromises.
Chris
Mahoosive! Good one🙂 I've have good results with 0.5-0.6 Qts for sealed. Of course high power handling and large Xmax help.
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You must remember that the final Qts is detremined from the box volume.
.707 is considered flat
Graphicaly I prefer .9 and any more than this things start to become boomy. jer
Don't some people prefer Qc=0.5 for optimum transient response and better integration with room gain and stuff?
I avoid drivers with a Qts of over .5 because the box volume they require gets large whether sealed or ported. Putting them in a too small enclosure means that big boomy hump with faster roll-off (weak bass extension).
For sealed boxes, I stay around .7 for the Qtc. Higher Qtc (smaller box) means that boomy hump. Smaller Qtc, such as .5 will mean a much larger box (given the same driver) with a smoother roll-off for better extension, however, for the small db in extension gained for the large box volume increase makes this undesirable to me especially with larger drivers. If space is a premium, .85 is not too bad, but 1 or more is no good.
Personally, I choose drivers of low Fs and Qts (.4 or less) for either sealed or ported subs.
For sealed boxes, I stay around .7 for the Qtc. Higher Qtc (smaller box) means that boomy hump. Smaller Qtc, such as .5 will mean a much larger box (given the same driver) with a smoother roll-off for better extension, however, for the small db in extension gained for the large box volume increase makes this undesirable to me especially with larger drivers. If space is a premium, .85 is not too bad, but 1 or more is no good.
Personally, I choose drivers of low Fs and Qts (.4 or less) for either sealed or ported subs.
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I pretty much agree with this. Even though I mostly prefer ported enclosures, I none the less have always liked low driver Q mainly because 1. Qts is determined largely by Qes which is a main factor of speaker efficiency, 2. Qts will rise during normal operation due to voice coil heating, so starting with a low Qts is of importance to me. Fs I don't like too low because speaker efficiency is proportional to Fs³, so it plays a huge factor. But then again, I'm not a home-theater buff who needs much response below 25Hz, so an Fs in the mid-to-high 30s works well for my tastes. An F3 in the high twenties is enough for my tastes in music, so it works out to my favor to accomplish whatever bass extension I need with ported enclosures.
Hi!
Can you please recommend some 15” or 18” drivers for a sealed box around 80L-120L, that would give a great bass sound, clean with good transients to around 30hz. This is for music only, at home, in a 40m2 room, so no need for extremely high outputs, say 100db at 30hz would be more than enough.
I was looking at the B&C 15BG100.
THank you and regards
Can you please recommend some 15” or 18” drivers for a sealed box around 80L-120L, that would give a great bass sound, clean with good transients to around 30hz. This is for music only, at home, in a 40m2 room, so no need for extremely high outputs, say 100db at 30hz would be more than enough.
I was looking at the B&C 15BG100.
THank you and regards
I use 0.35 to 0.8 as guideline for sealed. But EBP (=FS/QES) says more than QTS actually, an EBP below 100 is what is needed, and below 50 is best. Above 100 it's absolute not fit for sealed (for a woofer or subwoofer, for mid it does not matter).
I would use a smaller driver actually. I'm very fond of the 12" SB34NRX75-6 that needs about 125L and goes to below 30hz (F6). That would be my first choice for such a subwoofer.
The 15" Dayton UM15-22 can do that also (and even lower), but the QTC will be slightly to high (not that it becomes a real problem) in a 150L cabinet. Bigger (200L) would be slightly better.
The 15" Dayton UM15-22 can do that also (and even lower), but the QTC will be slightly to high (not that it becomes a real problem) in a 150L cabinet. Bigger (200L) would be slightly better.
Not so! It depends on the system's output impedance, desired BW.
Ditto any speaker cab alignment for that matter.
Yes, I know it's > a decade ago, but needed this 'given' corrected.