tuga
Legal Alien
What made you change your mind?
Ported or sealed box speakers. Which do you prefer?
- Thread starter lindsayt
- Start date
What made you change your mind?
Noise as a signal is how large? And then the distortion components of the tiny signal are how large? And then the nonlinear part of the distortion is how large? And then the part of that nonlinear distortion that is aliased into a particular audible frequency with enough magnitude to be heard relative to the music signal at that frequency is how large? To repeat, if you make any sort of effort to quantify the size you will see it is negligible.
Of course the audiophile phenomenon doesn't work like this. People promoting audiophile hardware such as John Atkinson (I don't know the other chap you mentioned) do not quantify things in the manner of the technically literate because it hinders rather than helps the cause. They will mention some often perfectly valid effect and then fail to quantify it in the way competent engineers, scientists and, quite frankly, anyone with some common sense would do. They are doing their job by enhancing interest in audiophile products and ways they can distinguish themselves. Good luck to them.
Because it strongly supports the marketing of top of the range home audio speakers. To most audiophiles the further above 20 kHz the first resonance the better the product. It is just obvious and if this is done with an exotic material the extremely high price is obvious as well. Over-engineering sells luxury products.
When Scan-Speak brought out their beryllium tweeter less than 10 years ago it out sold all their other products in terms of revenue (the price and the margin is very high). Since then pretty much every other driver manufacturer has jumped on the bandwagon and brought out beryllium tweeters usually at ever more ludicrously high prices. This isn't about engineering but the marketing of top of the range luxury products. Engineers tend to be in a position not to confuse the two but this is much the less case for the average home audio enthusiast because guidance on genuine technical performance disappeared from the mainstream press in the late 70s with the arrival of the audiophile thing.
This isn't to say these tweeters aren't technically top of the range because in most cases they are. In fact some of the later ones are getting larger which is a much better use of the properties of materials like beryllium to gain real performance rather than pushing the lowest resonance needlessly higher.
How have you determined what ported bass sounds like? Our two ears and a brain lack a mechanism to distinguish the source of sound in a room at low frequencies in the way they do automatically at higher frequencies. If a sealed speaker was equalised to have the same frequency response as a ported speaker (and the driver in the sealed speaker was large enough not to have distortion issues) would you expect to hear a ported speaker, a sealed speaker or something else?
tuga
Legal Alien
Now post the transient response of the room in which you wish would compare the transient response of these two speakers. Conclusions?
(I will spare you an engineer's knee-jerk reaction to waterfall plots).
tuga
Legal Alien
I consider myself an extremely sceptical audiophile and in spite of my limited technical knowlege I am firmly in what is usually referred to as the objective camp. But I am not deaf.
Why do you need virtually "transparent" sources and amplification with infinitesimally small amounts of noise and distortions and crosstalk if the speaker produces comparatively massive amounts of HD, IM and non-linear distortions, etc., plus the room interference?
You shouldn't be able to hear the difference between say a UCA222 and a Chord Mojo or between a T-Amp and a Marantz PM6003...
John Phillips
pfm Member
Not answering for @fatmarley but for me. Listening back-to-back in my dealer's listening room to ATC's SCM40A (sealed) and SCM50A (ported) convinced me there was nothing essential characterising the sound of ported speakers.
tuga
Legal Alien
That has not been my experience.
Perhaps your opinion would be different if you'd made a more meaningful comparison with a sealed box SCM50A which, alas, doesn't exist...
Did you listen with familiar tracks of classical music? I guess it ultimately depends on your references and which particular aspects of performance you are more sensitive to.
Fatmarley
"It appears my intelligence circuits have melted"
What ever I say isn't going to change your mind and that's exactly how I felt a few years ago. I build my own speakers now and lets just say that i'm very careful about what drivers I choose and how I tune my speakers because I detest bloated, boomy or subjectively slow bass. If you're anywhere near Cheltenham, you're more than welcome to have a listen.
tuga
Legal Alien
Why do you consider yourself to be objective when you have no interest in the science of what is going on? In order to be objective you have got to have relevant knowledge and understanding to be objective with. You have taken no interest in the sizes of the quantities involved that would be required to make an ultrasonic tweeter resonance audible. You are simply taking it on faith that it is audible and looking to doubtful sources to confirm that faith. This isn't being objective. It isn't being subjective either. It is being an audiophile.
What does virtually transparent mean. What does massive amounts of HD, IM and non-linear distortion mean. Do the numbers and compare them to audibility thresholds. You might be surprised. Why can we recognise the sound of someone's voice despite massive and different room interference patterns? Why doesn't it seem to matter (at least at some frequencies)? Obtaining this sort of information would enable you to be objective.
If you were objective about it then you would set about knowing why they sound different to you. Which differences are above an audibility threshold? If none, where does the explanation lie?
tuga
Legal Alien
I won't change my mind because of your opinion but I was interested in what made you reconsider.
You've designed and build a ported speaker that sounds as good as a sealed cabinet to your ears. That's perfectly plausible.
tuga
Legal Alien
Why can we recognise the sound of someone's voice despite massive and different room interference patterns but not the decay of a ported speaker?
I think that you are being disingenuous.
Have you tested your audibility thresholds?
Are you a trained listener? (if you took the Philips Golden Ear Challenge you'll know why I am asking)
There's listening for pleasure (tasting) and there's listening to assess performance (observation).
Observation may have its shortcomings but it is a valid method.
I answered that question earlier in the thread. I have opted to skip the rest and stop because no discussion has taken place over the last few posts and we are only partially on topic.
What speaker exhibits this, and what material is it obvious with?
ToTo Man
the band not the dog
My experience of recording musical instruments using both DI and microphones is different to yours, a spectrum graph shows a steady roll-off but there is high frequency content all the way up to the 1/2 the sampling frequency, as there is with the majority of commercially produced CDs containing instruments capable of producing overtones.
Is this HF content genuine content or a distortion artefact? I believe it's genuine content because if you apply a low-pass filter to remove everything above say 15kHz then the resulting sound is inferior to my ears, but is I suspect acceptable to the majority of casual listeners. (All audio on YouTube, for example, has a brickwall low-pass filter at around 15.5kHz) A low-pass filter at 12kHz would make things unlistenable for me...
If you want to experience the effect of a low-pass filter without messing about in the digital domain, borrow a pair of speakers that use the Celestion HF1300 / Coles 4001 or Celestion HF1300 / Celestion HF2000 combo and disconnect the supertweeter. Your now listening to music that rolls off at 14kHz. Does it sound as high-fidelity as when the supertweeter is connected? I suspect not...
SACD is a special case because DSD has inherent noise that increases with frequency. If you do a spectrum analysis on a DSD file that's been converted to PCM you can clearly see where the HF noise begins (>30kHz). A well-designed DSD DAC ought to contain a low-pass filter to remove this ultrasonic noise.
tuga
Legal Alien
The topic is about personal preference between ported vs. sealed cabinet, how are a couple of questions about listening ability off topic?
Unless you don't do listening.
There are three ways to go about it: listening, theory, and a combination of both.
Listening is a valuable tool.
Wasn't the negative impact of TIM's first noted by listeners (who must have had to put up with naysayers) before Otala et al. identified the cause and developed a measurement?
Anyway, nice talking to you. I always learn a thing or two from some of your posts.
moo-fi
pfm Member
Toto man you raise the question about hf I was pondering, extreme HF is it an artifact or low level signal. My speakers manufacters make a big deal about their tweeters going up to 30khz and beyond. Yet only a few microphones get anywhere near this. The typical SM58 is done by 12khz along with most large condensers. Only a few get up really high such the earthworks a that Tuga mentioned and the DPA I use for classical work
So it comes down to how fast they roll off and at what level do we perceive sound. This article is good if rather long:
https://mynewmicrophone.com/complete-guide-to-microphone-frequency-response-with-mic-examples/
So it comes down to how fast they roll off and at what level do we perceive sound. This article is good if rather long:
https://mynewmicrophone.com/complete-guide-to-microphone-frequency-response-with-mic-examples/
Tony L
Administrator
Lots of top end with even some vintage recordings, e.g. I remember looking in Audacity at a track from Miles Davis superb Someday My Prince Will Come album (which everyone here will have, obviously, as not to is to demonstrate quite exceptionally poor taste) and there is lots of treble content right up to the CD cut-off point. It is one of the best recordings of a muted trumpet I have ever heard, it really does sound like he’s right in front of you! Plenty of HF from that trumpet!
PS I’ve never quite understood this as the comment above about most mics, especially lovely vintage tube-driven ribbons as I assume was used here, do roll off at about 14 kHz. I guess the positioning must have been close enough to really get the energy of the thing.
PS I’ve never quite understood this as the comment above about most mics, especially lovely vintage tube-driven ribbons as I assume was used here, do roll off at about 14 kHz. I guess the positioning must have been close enough to really get the energy of the thing.
moo-fi
pfm Member
The microphone used was a rather nice valve, I actually have a couple of similar ones and yes they do run out of steam quite early.
Trumpets are an interesting instrument to record, the primary frequency range tops out at 1khz, but they have a really strong harmonic at 5khz which I suspects gives them that bright sound. After that the level of harmonic's drop of rapidly.
Trumpets are an interesting instrument to record, the primary frequency range tops out at 1khz, but they have a really strong harmonic at 5khz which I suspects gives them that bright sound. After that the level of harmonic's drop of rapidly.