As you know my knowledge and vocabulary are limited and I am not very good with technical terms but bear with me for a second.
You're vocabulary around this is fine
Imagine a series of quick successive notes played on a kick drum.
The step reponse of a sealed cabinet shows a quick return to 0V whilst that of the ported cabinet continues to oscilate (ring) for a bit.
Won't this post-ringing affect the speaker driver's ability to accurately reproduce the ensuing note and the one after?
Yes, this will affect the (frequency-dependent) "speed" of
everything that the speaker plays. You can think of it as though the entire signal from start to finish gets "convolved" with the speaker's "transfer function". It will most definitely affect the speaker's accuracy, as you say.
The question, though, is whether the effects will be audible. I guess I can do two things to try to convince you. Firstly, let me refer you back to the study I talked about in
post #181. Look at the group delay in the low bass for those stimuli (Group A) for which no audible difference was discerned. They are literally (way) off the chart.
Secondly, let me suggest you try this piece of
software. It's a little piece of freeware that you can load any WAV file into and then play around with phase distortion, and then ABX test yourself with. If you want to emulate the phase distortion caused by a ported speaker, click "low filter" and "phase 24dB/octave", then choose your enclosure resonance Q factor (values under 0.71 are overdamped, values above 0.71 are underdamped).
FWIW, I've analysed the output impulse response and it appears to be doing what it claims to do. NB however, at least with my soundcard, there's a tell-tale lag when switching between stimuli, which totally invalidates the ABX test aspect of the software.
@Duke, would you be interested in having a go with this, too? It's also possible to model the phase distortion caused by e.g. a 24dB/octave mid-tweeter crossover...
Transients (attack and decay) are an essential part of the timbre characteristics which make the sound of instruments disctinctive.
So you insist
Yet decades of research has attempted to establish that humans can hear the levels of phase distortion that you say are a problem, and again and again humans have failed to...
Frequency response does not provide any information regarding the speaker's ability to reproduce transients.
Well, it provides some but not all the information. For closed and ported systems, the bass and treble roll-offs are largely minimum-phase. The frequency response won't tell you directly about energy storage or excess group delay caused by crossovers (although a fair bit can be inferred).
Only anecdotal experience with the old Monitor Audio Studio series from the early '90s.
I guess you will have anticipated what I might say about uncontrolled variables and sighted bias etc when it comes to that...?
Have you never listened to the effects of room resonances in the bass? Do you think it's only the peak that is audible or also the tail?
Well, I must admit I haven't put as much work into this question as into the other questions we've been discussing. Conditions are very different in different rooms and the decay times are very long, even compared to those of ported, low-tuned, low-frequency systems.
My inclination would be to say that, with most music in most rooms, these decays probably won't be audible per se - except of course in the frequency domain, in which respect they will tend to be extremely audible as peaks and dips in the response. Though I'm sure with the right signals they could be quite easily made to be audible (i.e. with very sharp transients with no decay of their own).
However, I wouldn't pretend to be able to give a knowledgeable answer to this question
I think
@Duke would have looked at this in a lot more detail than I have...
Are they safe to reproduce or will they blow my tweeters?
Yes sorry, should have warned you. They are quite loud, please keep the volume low