Originally posted by: ribbon13
Ken, I say that on virtue that MTX calls the 5i's 'mini-monitors'. Also from personal experience building many many speakers over the years. I can get an F3 well below 60hz with a ported 5.5" system using even the cheapest drivers. That, and that entire range, even the 600i (priced at $200 msrp individually) don't use the 'variation' spec. Because anechoic variation is meaningless without other data. Both top and bottom range are the -3db frequencies.
Good manufacturers dont go 43-19.5kHz±3db alone, get give you pretty MLS graphs!
http://speakerbuilder.net/web_files/Projects/Eros%20Project/erosmk2.htm
Sorry, man, and no offense, but you're mistaken on the meanings of the bottom & top numbers.
The top and bottom range numbers in quoted FR specs do
not represent an F3 mark or anything of the sort. In fact, the absence of a +/- qualifier is a solid bet that the component is
not anywhere near flat
nor only down by -3dB at those numbers.
Where to begin ... For starters, I never said the MTX 5i's would definitely not reach to 50Hz (or the mfgr's quoted 48Hz) -- I just indicated that the FR spec they provide on their Web site is worthless without a +/- qualifier, and that we don't know at what dB level 50Hz frequencies are reproduced. Without a +/- qualifier, one cannot assume that this speaker's FR is anywhere near flat out to the lower or high number in the quoted range -- and in fact, we can prolly assume it's
not because if it were, the mfgr would almost
certainly provide the qualifier to validate the speaker's performance and their quoted spec. Nor do we have any idea at what dB level those outer frequencies are reproduced at -- like Operandi stated, "My clock radio might go down to 20Hz, but at -100dB." (I'm paraphrasing there.) And as I stated before, audio engineers and professional equipment reviewers have -- for decades -- blasted mfgrs for hiding their equipment's true FR performance by intentionally omitting the +/- qualifier. They don't omit the qualifier out of some unspoken 'understanding' that it's an "F3" point, because there has never been any such understanding. They do it out of deception. Credible reviewers' tests after tests after tests after tests over the years have proven this to be the case, so much so that it's common knowlege among audiophiles.
To support my position here, I offer the following links and accompanying relevant excerpts:
This is a particularly excellent article on speaker testing that I bookmarked several years ago and still refer to every so often. For anyone wanting a good explanation of the various characteristics of speaker performance and how they are measured, this is a particularly good article (and it's not too long).
Here's a noteworthy excerpt:
"Frequency response specs describe how a loudspeaker will reproduce a flat electrical reference signal. The speaker receives this signal and reproduces it as well as its design permits. Since a speaker consists of many moving parts, there are several losses that can occur. So, the frequency response measurement produced by the loudspeaker is quite different from the original electrical input signal received by it. Frequency response ratings are typically described in terms of a ±3dB range or not at all. For example, a frequency response rating of 40 Hz to 20 kHz ±3dB indicates that the loudspeaker will be centered within a 6dB-tolerance window covering that range.
If the frequency response is stated without the plus or minus tolerance, the relative smoothness is up for interpretation. Unless there is a stated test method used for deriving the low-frequency cut-off, values can be misleading.
[Bolding added by me.]
So my question is why would that writer say what he did in the last two sentences above if it were understood that the upper & lower numbers in a FR spec were representative of an F3 point?
Here's another article -- see the bottom of page 2 and top of page 3.
Notable excerpt:
"I don?t have a problem with over-specified frequency response, provided the equipment actually does have the response claimed. Where I do have a problem is where claims are made for wide frequency response that the equipment cannot possibly deliver. SACD is a perfect example where we had a raft of propaganda extolling the massive audio bandwidth, whereas the designers of the noise shaping filters had set the practical bandwidth to be essentially the same as that of a regular Compact Disc.
Of course frequency response is meaningless unless the spread of levels to be expected over the specified range is also given. Thus if the frequency range is quoted without a number of dBs level range, it is a cosmetic specification.
[Bolding again added by me.]
Want me to keep going? Okay
:
What the numbers can and can't tell you
Notable excerpt:
"For instance, you might get a frequency-response specification such as "40 Hz-22 kHz," but unless the spec also tells you the variance within however many decibels (+/- 3 dB, for example), the numbers are essentially useless. The speaker may well reproduce 20 Hz, but that tone could be 20 dB "down" from (or below) "flat" response, meaning you won't really hear 20 Hz from that speaker. Additionally, how a speaker is measured can affect the response. Was it measured in a room or in a reflectionless anechoic chamber? Where was the microphone placed to measure the response? Essentially, a frequency-response measurement by itself, unaccompanied by a critical review, is pretty much useless!"
[Again, bolding added by me.]
And what the heck, how about
one more.
Notable excerpt:
"Frequency response is the range of sound frequencies that the speaker can reproduce.
The values provided for most speakers are meaningless, because they do not specify how flat that response is. For example, professional studio-monitor speakers may provide 20 Hz to 20 kHz response at ±1 dB. Expensive home audio speakers may provide 20 Hz to 20 kHz response at ±3 dB, and 40 Hz to 18 kHz response at ±1 dB. Computer speakers may claim 20 Hz to 20 kHz response, but may rate that response at ±10 dB or more, which makes the specification effectively meaningless. A reduction of about 3 dB halves volume, which means sounds below 100 Hz or above 10 kHz are nearly inaudible with many computer speakers."
[Again, bolding added by me.]
And why not
one for the road?
(scroll down to "Speaker specifications information: How to read speaker specs")
Proverbial "notable excerpt":
"Frequency Response is the frequency range to which the speaker can respond. A full-range speaker is a speaker designed to reproduce all or most of the sound spectrum within human hearing (20Hz - 20KHz). Typical speakers are not able to play back this whole frequency range.
Please note that with frequency response, many companies publish only "Half Specs." For example, 50 to 20 kHz is meaningless with knowing what the deviation is from the reference level at a specified frequency (typically 1 kHz). For example 50 to 20 kHz + or - 3dB is decent and + or - 20 dB is atrocious (quite a useless product). So both pieces of information are necessary to be useful, so be suspicious of new gear with low prices and great looking specs.
If the speaker just says frequency response 30-25,000 Hz and no other information like deviation and how it is measured, this "spec' tells you absolutely nothing. It could be interpreted to meaning nothing more than if you put any frequency in between 30 and 25,000 Hz, SOMETHING will come out. Frequency response, without some statement of the error band, the measurement conditions and such, doesn't mean a thing.
[Bolding and a few grammatical 'repairs,' without affecting meaning, added by me.]
Now, except for the first site I linked to, these are all sites I just Googled tonight and copied excerpts from for this thread. If I wanted to take the time (and no, I don't
) I could go back thru 25+ years of my audio magazines and scan articles written by the likes of Julian Hirsch, Craig Stark, David Ranada, Ken Pohlman, Bob Carver and a myriad of other brilliant and renowned audio engineers and reviewers who've all said the same things. As I've said, this is common knowledge among audiophiles (and even quasi-audiophiles like me
).
So no offense, man
, but you're just mistaken on this. If you can cite some credible source that says that the top & bottom numbers in FR specs without +/- qualifiers (aka "variances" or "dB level ranges" or "tolerance") are somehow
assumed to be F3 points, let's see it. I don't know where you got that idea, 'cuz again, your post is the first I've ever heard of that notion.
Whew ... long post. :Q
:moon:
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