All other things being equal: 8" Driver, 20 litre cabinet, which system offers the best performance.
Fair question.
A ported Tannoy SFX 5.1 sub claims -6dB @45hz (20 litres)
A bandpass Corsair SP2500 sub claims -3dB @35Hz (20 litres).
My side-hustle involves me getting all these cabinets and drivers for (net) free.
All things being equal, how will the Corsair driver perform in the (more practical) Tannoy box?
Claims without response curves and measurement conditions don't give much useful information.
The Corsair SP2500 sub uses integrated amps and DSP, it could be using 20dB of equalization to be -3dB @35Hz.
All things being equal (TS parameters of the drivers) a driver best suited for a ported box won't be best for a BP4.
It is impossible to predict how a driver will perform in a box without knowing both the driver's parameters and the box parameters.
And we still don't know what you mean by best performance.. 😉
The Corsair SP2500 sub uses integrated amps and DSP, it could be using 20dB of equalization to be -3dB @35Hz.
All things being equal (TS parameters of the drivers) a driver best suited for a ported box won't be best for a BP4.
It is impossible to predict how a driver will perform in a box without knowing both the driver's parameters and the box parameters.
And we still don't know what you mean by best performance.. 😉
Vented=will go slightly lower (but with a steeper rolloff), wider usable bandwidth, easier to build, lower impact if the Fb is off slightly.
4th order bandpass = will go almost as low as vented (assuming 0dB passband design) but with shallower rolloff, narrower usable bandwidth, but great THD reduction within the passband, built-in physical protection for the driver, but more difficult to build, much greater impact if Fb is off slightly.
4th order bandpass = will go almost as low as vented (assuming 0dB passband design) but with shallower rolloff, narrower usable bandwidth, but great THD reduction within the passband, built-in physical protection for the driver, but more difficult to build, much greater impact if Fb is off slightly.
One major advantage of bandpass is that it acoustically filters the distortion products of the woofer.
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For that it's difficult to hear when it clips.
In 4th order you do not see the driver (if no glass permits insight into the box).
So you do not have control if you overload the driver.
It happens easier in these alignments like 4th or 6th order that people fry their basses at parties or PA use.
In 4th order you do not see the driver (if no glass permits insight into the box).
So you do not have control if you overload the driver.
It happens easier in these alignments like 4th or 6th order that people fry their basses at parties or PA use.
4th order bandpass in terms of usability is on par with a sealed type. 6th order and TL/tapped horns/paraflex/BR etc are better with driver cooling, efficiency etc. In current times we could easily use a software DSP (APO eq is free) or any similar device to give the amp and the driver precisely cut sound band to work with. So I would go with something like ported or TL (assuming the TS params allow it). In my personal home system I use many large sealed subs, but for 1 sub, I would go for efficiency. Nevertheless 8" in 20dm3 is not something I would use as a subwoofer, no matter it's parameters, Hofmann's rule is valid always.
After extensive albeit subjective testing I'm wondering why the bandpass format was favoured the Corsair box.
The Corsair driver is preferred to the Tannoy driver in the Tannoy box - more rumble less boom.
After converting the Corsair box to vented (tuned to 50hz), both drivers fared better than in the bandpass design. I'd guess output was around 3dB better and far smoother.
I'm struggling to understand why anybody would deploy a bandpass sub in a home. Maybe they're suitable for cars where varying air-pressure is a greater consideration and power is "free"?
The Corsair driver is preferred to the Tannoy driver in the Tannoy box - more rumble less boom.
After converting the Corsair box to vented (tuned to 50hz), both drivers fared better than in the bandpass design. I'd guess output was around 3dB better and far smoother.
I'm struggling to understand why anybody would deploy a bandpass sub in a home. Maybe they're suitable for cars where varying air-pressure is a greater consideration and power is "free"?
Well, it's not actually "home", but my 10" bandpass subwoofer is still in use at my brother's bar, albeit with a new driver. The build provides built-in physical protection for the driver and the distortion-filtering that the 4th order acoustic bandpass provides allows the system to sound clean, even at volumes you wouldn't expect such a cheap 10" driver to produce. I even added a sort of two-stage protective circuit to the build to protect the driver from being destroyed. Stage one drops the output at Fb by 2dB. Stage 2 effectively takes the driver offline. They haven't been able to trigger stage 2... yet 🙂.
INF10 have params that would be good in BP6 too with dsp to protect it from bottoming out. Have considered it an option? And what temperature is the magnet in the small closed volume of BP4. I always thought there the VC will be hot after some time and power compression will occur.
The INF10 driver has a flaw that basically prevents it from being used in a vented or 6th order BP design. Its design allows the voice coil former to hit the backplate pretty easily at higher power levels. It's why I moved it from a vented alignment to a 4th order one designed with a bit of gain in the passband (so a smaller sealed section). Even then, it still managed to self-destruct when used in the bar. The Dayton audio driver that replaced it is still working fine a few years after installation. The replacement driver is a metal-coned one that I hope does allow some of the heat to be wicked away. I recently had the subwoofer back at home for a few days for some maintenance (repainting, etc.). Apart from a bit of cone-sag, the driver looked fine.
I'm still not buying any of it. If you need to batter the sh*t out of a driver to achieve the desired result - you should probably buy a bigger one. I cannot find a use for bandpass outside of a motor vehicle or a rented PA system.
I recall, in my youth the local DJ worked at two venues. With 120w + 120w he covered the college disco using 2 x 2 x12" + 2 x 15" w-folded horn. For the school disco he left the bass bins at home (noise complaints). At parties our local sound system would rock the using a Simms-Watt PA 200 valve amplifier.
Throwing 400 watts+ at a bandpass in the boot of car just seems nonsensical. Just so I understand . . . an inefficient is created requiring more power to keep up with other designs? Steps are taken to protect the driver against the the excessive power required?
To me, it's a parallel: the doctor writes a prescription to help you gain weight. He then writes four other prescriptions for drugs to combat the side-effects of the first prescription.
Christmas rant over.
I recall, in my youth the local DJ worked at two venues. With 120w + 120w he covered the college disco using 2 x 2 x12" + 2 x 15" w-folded horn. For the school disco he left the bass bins at home (noise complaints). At parties our local sound system would rock the using a Simms-Watt PA 200 valve amplifier.
Throwing 400 watts+ at a bandpass in the boot of car just seems nonsensical. Just so I understand . . . an inefficient is created requiring more power to keep up with other designs? Steps are taken to protect the driver against the the excessive power required?
To me, it's a parallel: the doctor writes a prescription to help you gain weight. He then writes four other prescriptions for drugs to combat the side-effects of the first prescription.
Christmas rant over.
most of the time front loaded horns, some times they are with ported chamber.