Hi all,
From my experience I tend to favour the higher BL, low Qts woofers (in ported designs) - as they give a much tauter sound to me with more tactility.
But, how low can you typically go before the effects of driver Qts on tightness are non-perceivable? Given that very low Qts (<0.2) drivers are quite expensive I thought I would pose the question here before purchasing.
Specifically, I am currently using a B&C 12CL64-4 (4 ohm) with a Qts of 0.25 in a 40L cabinet tuned to 50Hz from 40-1200Hz. If I were to move to the 12CL76-4 (Qts 0.19) or 12NW76-4 (Qts 0.15!) how audible would the 'tightness' be? Or am I fixated around a parameter which is overshadowed by other effects? 😕
Thanks in advance,
From my experience I tend to favour the higher BL, low Qts woofers (in ported designs) - as they give a much tauter sound to me with more tactility.
But, how low can you typically go before the effects of driver Qts on tightness are non-perceivable? Given that very low Qts (<0.2) drivers are quite expensive I thought I would pose the question here before purchasing.
Specifically, I am currently using a B&C 12CL64-4 (4 ohm) with a Qts of 0.25 in a 40L cabinet tuned to 50Hz from 40-1200Hz. If I were to move to the 12CL76-4 (Qts 0.19) or 12NW76-4 (Qts 0.15!) how audible would the 'tightness' be? Or am I fixated around a parameter which is overshadowed by other effects? 😕
Thanks in advance,
Yes
well, plus a little nuance.
A different Qt means in some cases a major difference in the freq resp.
So yeah it's not so weird that you hear differences.
But that doesn't have anything to do with a "tight" bass, but more lack of it.
Which, I guess, is perceived the same way.
In general all speakers can actively corrected to have the same Qt anyway.
(even in a BR system, although that is a little more fiddly).
Also, with most speakers, the non linear effects around the Fs are just all different.
So in the end it's a not even comparing fruits anymore, taking also all the other variables into consideration.
I've found myself liking drivers with low Q factor (mostly Qes) the same way as you.
I'm using <0,2 woofer on my open baffle as it gives me super detailed multi-layered controlled bass. Yes, it's not so much, but quality over quantity.
I think your logic is just right. A lightweight membrane with a strong motor is the key.
I'm using <0,2 woofer on my open baffle as it gives me super detailed multi-layered controlled bass. Yes, it's not so much, but quality over quantity.
I think your logic is just right. A lightweight membrane with a strong motor is the key.
I generally like low Qts drivers in ported cabs.
Easy to get the EBS alignment I prefer. The 'missing' bass level can be fixed easily either by placement via room gain or with a simple shelving tone control which (pre-)amps used to have.
That said box calculators usually suggest a ludicrously small box tuned way to high.
Generally what works is a volume around Vas and a port tuned to driver Fs.
Still usually needs a bit of playing around to avoid a bass hump.
Easy to get the EBS alignment I prefer. The 'missing' bass level can be fixed easily either by placement via room gain or with a simple shelving tone control which (pre-)amps used to have.
That said box calculators usually suggest a ludicrously small box tuned way to high.
Generally what works is a volume around Vas and a port tuned to driver Fs.
Still usually needs a bit of playing around to avoid a bass hump.
I find that low Qts LF drivers sound best in ported or horn loaded cabs, but there are some exceptions depending on alignment and tuning. HavIng built many ported cabs, a Qts of .38 to .40 is the magic number is optimal IMHO. A lower Qts is good for a small box, but the corresponding alignment doesn't sound right to my ears (higher tuning frequencies can worsen the midrange spill from the port). Higher Qts in a ported cab sounds sloppy and slow to me, given you need a very large cab to get the response flat. I find than the higher Qts (sealed box optimised) woofer just doesn't have the dampening to deliver tighter low end in such a relatively large box tuned lower than driver Fs - weird sonic things happen when you ask an LF driver to play lower than its own Fs.
For a sealed box, I really like drivers around .35 to .50 Qts. Any lower, you get very little bottom end, although this is fixable with EQ to a certain point. Any higher, you end up with a huge enclosure to get reasonable dampening. I generally don't like anything higher than .65 system Q, especially when you have speaker placement issues that dictate placement close to walls and corners. I really dislike sloppy low end. I'd rather listen to a speaker with less but tighter low end than one with very low reaching, boomy LF (sort of like you get with a cheap subwoofer cranked up way too high).
To sum it up - yes you can hear the difference between a system Q of .6 and .7, but it depends on a few other factors like speaker placement, which can have a bigger audible effect than just the system Q itself.
For a sealed box, I really like drivers around .35 to .50 Qts. Any lower, you get very little bottom end, although this is fixable with EQ to a certain point. Any higher, you end up with a huge enclosure to get reasonable dampening. I generally don't like anything higher than .65 system Q, especially when you have speaker placement issues that dictate placement close to walls and corners. I really dislike sloppy low end. I'd rather listen to a speaker with less but tighter low end than one with very low reaching, boomy LF (sort of like you get with a cheap subwoofer cranked up way too high).
To sum it up - yes you can hear the difference between a system Q of .6 and .7, but it depends on a few other factors like speaker placement, which can have a bigger audible effect than just the system Q itself.
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Is the "tightness" frequency range standing in the low-end where the Q becomes important regarding the room ? Is thighness, chest, not in the 80 to 150 hz range ?
Maybe it is more the tipology of the load, i.e. its group delay that is important than the 0.2 to 0.4 Qts choice for a vented cabinet and the total amount of Sd if "just" talking of tighness, like the filter slope first?
I do like better sealed with Qtc between 0.5 to 0.7 when talking of subjective tighness, not so because of the low end slope but perhaps because the group delay is better in the upper bass where the tighness, chest impact stands VS a vented cab (at least that I'm saying to myself not knowing if true enough... I assume the dopler effect is also better with a vented at iso Sd vs a sealed)
But also see it has to see with the quality of the DAC as well as room modes... many modern delta sigma chips have not so tight bass imho. A little off topic but to say the long thinking between a driver choice between a 0.2 Qts or 0.4 Qts is not first on the list here.
my two cents only.
Maybe it is more the tipology of the load, i.e. its group delay that is important than the 0.2 to 0.4 Qts choice for a vented cabinet and the total amount of Sd if "just" talking of tighness, like the filter slope first?
I do like better sealed with Qtc between 0.5 to 0.7 when talking of subjective tighness, not so because of the low end slope but perhaps because the group delay is better in the upper bass where the tighness, chest impact stands VS a vented cab (at least that I'm saying to myself not knowing if true enough... I assume the dopler effect is also better with a vented at iso Sd vs a sealed)
But also see it has to see with the quality of the DAC as well as room modes... many modern delta sigma chips have not so tight bass imho. A little off topic but to say the long thinking between a driver choice between a 0.2 Qts or 0.4 Qts is not first on the list here.
my two cents only.
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My 2cents here. In a normal oscillation mechanical system, the Q ( Quality factor) refers to how the overall system is damped. A high Q means the resonant frequency is very narrow and not damped. A low Q means the system is heavily damped and resonance is spread over a wider frequency. So essentially a low Q means the cone will stop moving faster than a high Q system. Total Q is a function of two Qs, mechanical and electrical. It is typically determined by electrical Q which is much smaller... which simply means there is a electrical system braking your speaker once electrical signal cuts off...
So maybe that us the reason you like it...
Oon
So maybe that us the reason you like it...
Oon
The room.
A RT60 of 0.5 sec at 50Hz is very good. Now look at the Q of that comparred to the Q of any speaker.
What matters is the spl at your ears, nothing else.