I get it, I'm just thinking of how error is introduced into the FT as the length of time changes, as in doing an FFT on 1024 samples vs 2048 on a signal that isn't necessarily static. I guess it's not really practically relevant for audio because 2048 samples is approx 1/25th of a second for a...

I have a follow up question on FTs. How does the heisenburg uncertainty theorem apply to FTs? The way I'm understanding this, a Dirac IR used to derive FR would be less accurate to the transducer's behavior over time compared to a sine sweep, which is why I assume sine sweeps are the standard...

I think I get where I was mixed up, a FR consists of complex numbers plotting out each sample's magnitude and phase information. The magnitude is "real" and the phase is "imaginary" in the display of the FR, so IFT takes the fourier coefficients to reconstruct each sinusoid and combine them back...

Ok, I'll have to do some more reading. I'm obviously having trouble with the IFT, so I'm off to do my homework lol.

Right, as frequency is a function of amplitude cycles over time, the derivation of frequency requires no assumptions to conduct the Fourier transform for the purpose of easily analyzing the frequency content of the complex signal captured in the Dirac delta IR. The issue now is that converting...

Right, the assumption is where I have a problem. I don't want assumptions made when the assumption is not necessary given the data being assumed is already collected in order to generate the FR in the first place. An assessment on quality also involves examining the phase alignment and resonance...

The way I am understanding this, the problem is with the inverse of the causal relationship between IR and FR not necessarily being true. If I'm mistaken at any point, please correct me. IR by definition contains three dimensions of information (frequency, amplitude, time), thus has all the...

My question is whether you can derive/reconstruct either the original Dirac delta IR or the CSD that is typically plotted using the IR by using only the FR as a data set. I'm contending that you are working with incomplete information and making assumptions as a result when working solely with...

I can't get there, the FR will not comprehensibly describe irregular decay and resonance behaviors that can not be displayed outside of a CSD because those behaviors are not necessarily occurring alongside the same minimum phase impulse that the FR is derived from. I think it makes sense that...

@Doltonius @VNandor Maybe it'll be easier to describe my conceptualization of what is going on to make sure we are on the same page. So at the ADC, we record magnitude across time at discrete time intervals (whatever sampling rate it is) and run this data set through a FFT to get the...

I'm not a math Asian so I'm trying to wrap my head around this a bit ineptly, but I can't help but think an assumption is being made here that multi-driver systems that combine different driver operating principles are by definition minimum phase because they are indistinguishable from another...

He made a part of the IR shorter by reducing the amplitude in a specific frequency band, thus directly causing a shorter decay, that's not in dispute. However, you wouldn't have an indication of how much the IR was shortened by exactly going by just the FR readout, and the fundamental frequency...

@Doltonius It seems we are talking about different things. I get what you are saying here, that doesn't mean that you know what the actual duration of the IR is, just that you can shorten some harmonics of bass resonance by destructively interfering with that frequency via EQ.

Yeah, music tests are the important one IMO because it's the closest approximation to how we are actually using our gear, thus gives us a good idea of what actually matters in terms of distortion.

I took a read, chinese isn't my native language so I had to use translate. From what I read there, what I'm taking away is that resonance and nonlinear distortion artifacts generated by bass frequencies occur at essentially the same time given the minimum phase characteristics of IEMs whether...

Same site, used the J stone music track.

You wouldn't be able to quantify the duration of a Dirac pulse IR by looking at an FR graph. The Fourier transform would indicate the presence and amplitude of decay, but not the duration because there isn't a time axis recorded. It's only frequency and amplitude. A CSD does introduce the time...

That makes sense in theory, but it's rather difficult to parse that information out by just reading the FR because each of those frequency ranges contains information originating from both the IR of lower frequencies and fundamentals/lower order harmonics of higher frequencies. A CSD is easier...

Tonality is dictated by FR and THD profiles that exceed audibility thresholds during music playback. I test at -39dB as my threshold in music, so I use stuff that measures below 1% THD (well below in the case of my current stuff) to avoid detectable noise. Odd order biased harmonics are...

Too much weight is given to how much information is conveyed by an FR graph IMO, FR graphs don't factor in the time domain at all and don't measure how accurately the transducer reproduces complex signals like music (as compared to the single tone sweep FR measurements use in general). It's...

Nah, I don't think you need to do either. If you are a mixing/mastering engineer you can do what I'm describing by ear very quickly, but you don't need such listening skills to watch the graphic visualizer and figure out what sounds look like mapped out on the graph. Experiment with big peaks...

Right, of course you aren't going to get good results if you aren't identifying and targeting distinct problems, you need to know what your target is before engaging. I'll try using my EQ tuning of the QDC V14 as an example to explain my strategy. I used 6 filters here to address certain...

I'm a bit curious about what your specific problems are. What are you trying to solve and what filters are you applying to solve them? "Smearing" as you describe it, sounds like IMD and aliasing caused by adding amplitude without compensating by dropping input gain. Your issues are vague to this...

@Dalmonegrig You remember how I had the idea that SBC was inferior to AptX innately? I tested that assumption by doing a double blind test using recordings of the same song using each codec at max bit rate, I can't tell a difference. That doesn't mean there can't be a reason codecs change audio...

The qualitative study I linked to by kamedo2 differs from that conclusion, notable degradation of signal quality at 128k AAC is observed using the 27 testing samples of music and significant degradation at 237k SBC using those same test samples. Bigshot and gregorio seem to also concur that 192k...