Sorry for idiosyncratic term but I was trying to find a word for speaker systems that use the tuning in a major way... oops, still struggling to find the right word.
Now bass reflex systems create a resonance exactly to counteract the speaker's resonance (as housed in the box) and you end up with a couple of resonances. On a good day, these act like the software says and even then you might not like the one- or two-note quality, I sure don't.
Not sure where tapped horns fit into that concept (and I never had a good word to say for the idea, theoretically speaking) and/or transmission lines.
I certainly don't know where Karlsons fit in.
I never understood this. I must have all good days because I have yet to make a reflex box that's just one or two notes?? I have tried sealed boxes and the sounded good. Reflex just as good when done right.
Rob🙂
That one and two note thing has probably more to do with room interaction than with the box itself, except when it is due to extreme misalignment.
Many people decide for a driver or box type or both without taking into account, where and how the box will be placed. If done the other way round, the chances for good sound are so much higher that the need for room treatment and signal processing can be greatly reduced.
That means of course to say Good Bye to religiously worshipping a certain box type and driver brand or model. It can also lead to the insight that a certain place is not good for any box, and you either rearrange your furniture or accept whatever you hear.
Many people decide for a driver or box type or both without taking into account, where and how the box will be placed. If done the other way round, the chances for good sound are so much higher that the need for room treatment and signal processing can be greatly reduced.
That means of course to say Good Bye to religiously worshipping a certain box type and driver brand or model. It can also lead to the insight that a certain place is not good for any box, and you either rearrange your furniture or accept whatever you hear.
Two big problems with even well designed (large, 1/3 the area of the active driver) ports for me. One is the port output is one full cycle behind the drive signal. If a box is port tuned at 30Hz then there is 33ms delay between the port output and the input to the electrical motor. That is scary close to echo. The second problem is the output impedance of the passive is quite high because it is a coupled resonator. What this translates to is more interaction with the room than the low Q sealed box which is more room independent.
Making lots of bass (tapped horns and so on) and making punchy fast bass are often different things in practice.
As for a-resonant tuned boxes, here back in the late 80's with use a second box attached to the first box as a coupled resonator which loaded the driver at its resonant frequency. This made a large box with another box sticking out of it on the experimental version. It worked okay. For size and final performance, very low Q sealed box has proved to be the best with the resonant frequency not to low. About 30 is as low as I usually go.
There is one thing seen as often confused here and almost everywhere in audio. The "linear" range of direct radiator loudspeakers is below the resonant frequency. Above the resonant frequency is a 12dB per octave (amplitude) roll off because the transducer is above its linear motion range. This roll off makes the driver "flat" in the frequency domain because radiation resistance matches up with that roll off to make the final output flat in frequency. It is not flat in amplitude.
With this in mind a recent install EQ'd a double 15 setup that had Q in box = .6 and Fb=76Hz. EQ'd this flat down to 40. It was very fast with that high midbass resonant frequency and sounded great to everyone. Maybe this is a better solution. Ideally, low Q in box (<=.5) and high resonant frequency. Higher resonance clearly means faster in amplitude motion response and low Q means more controlled motion. This is worth a try for an experimentally unstable guy like me, HAHA!
Then there is always feedback woofer systems. Anyone played with those seriously? I have not.
Making lots of bass (tapped horns and so on) and making punchy fast bass are often different things in practice.
As for a-resonant tuned boxes, here back in the late 80's with use a second box attached to the first box as a coupled resonator which loaded the driver at its resonant frequency. This made a large box with another box sticking out of it on the experimental version. It worked okay. For size and final performance, very low Q sealed box has proved to be the best with the resonant frequency not to low. About 30 is as low as I usually go.
There is one thing seen as often confused here and almost everywhere in audio. The "linear" range of direct radiator loudspeakers is below the resonant frequency. Above the resonant frequency is a 12dB per octave (amplitude) roll off because the transducer is above its linear motion range. This roll off makes the driver "flat" in the frequency domain because radiation resistance matches up with that roll off to make the final output flat in frequency. It is not flat in amplitude.
With this in mind a recent install EQ'd a double 15 setup that had Q in box = .6 and Fb=76Hz. EQ'd this flat down to 40. It was very fast with that high midbass resonant frequency and sounded great to everyone. Maybe this is a better solution. Ideally, low Q in box (<=.5) and high resonant frequency. Higher resonance clearly means faster in amplitude motion response and low Q means more controlled motion. This is worth a try for an experimentally unstable guy like me, HAHA!
Then there is always feedback woofer systems. Anyone played with those seriously? I have not.
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