Hello everybody,
I have a question that is nagging me since a long time. Me and my fellow loudspeaker geeks have noted that there are big tonal differences in subwoofer designs. We are very interested in Pro Audio and there is a variety of designs that are competing. I will name a few with pro's and con's
I would be very interested in an explanation what it is that I hear if it isn't alone in the frequency response.
cheers Finn
I have a question that is nagging me since a long time. Me and my fellow loudspeaker geeks have noted that there are big tonal differences in subwoofer designs. We are very interested in Pro Audio and there is a variety of designs that are competing. I will name a few with pro's and con's
- Ported Subwoofer: probably the most build subwoofer. They are small, have a medium efficiency, medium power handling, high usable bandwith
- Banpdass (Horn): Funktion One would be the most known brand using this type of enclosure. They are of medium size, have a high efficiency, high power handling, smal usable bandwith
- Tapped Horn: Danley Sound Labs as they inveted the design. Medium size, have a high efficiency, high power handling, medium usable bandwith
- Front Loaded Horn: EAW build some. Large size, high efficiency, low power handling, high usable bandiwth.
- Ported Subwoofer: the lower the tuning the less accurate they sound. Specially emphasis on certain frequencies and difficult to discern different tones that are close in frequency.
- Bandpass: accurate sound but you would need at least two different enclousures to get the same frequnecy response.
- Tapped Horn: Sound clean with emphasis on a few frequencies that stand out a bit.
- Front loaded Horn: Very clean and accurate sound easy to discern tones that a close in frequency.
I would be very interested in an explanation what it is that I hear if it isn't alone in the frequency response.
cheers Finn
Well it sure isn't that easy. There is little to no knowlege about group delay in low frequencies. I am not aware of any studies that do. The studies on group delay say that there are thresholds where a difference in group delay is audible but not if they are better or worse. As for the designs, I would argue that most of these designs have group delays that in a similiar range or I am not aware that some of these designs have execessive group delay.
Since you're primarily talking about pro audio, are most of your observations also at high output?
Properly functioning horns should result in lower driver excursion. That could be part of the difference you're hearing, especially if the ported box is experiencing high excursion to keep up with the horn-loaded ones.
Properly functioning horns should result in lower driver excursion. That could be part of the difference you're hearing, especially if the ported box is experiencing high excursion to keep up with the horn-loaded ones.
I experienced that in an A/B comparison with fullrange drivers you can hear the difference due to different time response between a backloaded horn and a reflex design. The backloaded horn turns its phase at aproximately 200 hertz. And the upper bass therefore sounded thin. F response being the same.
However your ear is not very good at hearing this fault without direct comparison.
However your ear is not very good at hearing this fault without direct comparison.
As well as group delay, directionality index differences between different designs can affect room response.
I would argue that the group delays and DI are not in a similar range if they are processed to have the same response, yet sound different.
The "ringing" seen as excessive group delay in resonant designs may be very objectionable (Icsaszar called it "simply unlistenable") on percussive music.
As was written in:
https://www.neumann.com/en-en/faq-monitors/
"The subjective effect of excessive group delay is a “loosening” of the bass or a “less dry” bass quality."
That said, with so much low frequency music produced with droning bass lines, it may be hard to distinguish between a cabinet that "rings" and one that is "dry", especially when in a typical room where decay envelopes are much longer than that of the transducers.
To my ear group delay affects different instruments depending on which frequencies are most affected. For example, high group delay around 250 Hz makes snare drums sound polite instead of rude as they do live. GD around 100 Hz subtly reduces distinction between kick drum and bass guitar -- but I heard that on headphones without testing on loudspeakers, so the room might affect audibility.