Flat response

To first approximation, no speakers have flat response. When they're placed in a real room, they're even worse. That's why room equalization software is considered so important these days if you want accurate sound.

Stereophile reviewed the speakers you mention. See http://www.stereophile.com/content/paradigm-reference-studio-20-v5-loudspeaker

Their bench test shows a peak just above 100Hz and another at about 20KHz. Most people can't hear that high, though.
See http://www.stereophile.com/content/paradigm-reference-studio-20-v5-loudspeaker-measurements

Personally, I'd consider the rapid fall-off below 100Hz to be unacceptable. (But that's why I have 4-way speakers.)

For their older designs, at least, the Axiom product pages have links to Soundstage reviews which give test data from the NRC, including off-axis response.

"Hit down to 50 Hz" just means that there's some output down there, not that it's anywhere near the sound level the speaker can can provide at 100Hz. If you look at the frequency response plot in my second reference, you'll see that at 50Hz it's 5dB down from the average, while it peaks at about 5dB above the average at about 102Hz. I certainly wouldn't call that particularly flat, nor would I consider a speaker with that kind of frequency response curve to be worth the price they're asking. My impression is that too many "high end" speakers are designed for their appearances, not for their audio capabilities.

Unfortunately, I haven't made any detailed examination of current speakers other than to groan at many of the horrible response curves reported in Stereophile. Many of their reviews are available online, so I suggest you browse through them yourself to see if any of those speakers are appropriate for what you want to do. Of course, they do tend to review speakers that are well above any reasonable price range.

You also should seriously consider auditioning speakers at local audio/video stores to find ones that you think you'll like, then look up their reviews to see how they fare. You're probably going to be living with them for quite a while, so it pays to invest the time needed to find the right ones.

A good place to start is the SoundStage speaker measurements page. As a first cut, you might consider speakers made by Harman itself (Infinity, JBL, Revel), as well as Canadian makers (PSB, Paradigm, Axiom, Energy), since that's where the Harman research started.

Pretty much all bookshelf speakers are going to start rolling off below 100 Hz. If you're using a sub, that's not a problem. The key is flat response from 100 Hz to 10 kHz.

There is fairly little content in music above 15 kHz. But lack of bass is much more perceptible.
The response should be at least to a clean 50Hz, for kickdrum, and any kind of stringed bass instrument.

I run a pair of heresies with single sub support (diy compound loaded), crossed over at 80Hz and achieve a well integrated response down to below 20 Hz.
I previously had used DIY satellite speakers (the size of book shelve speakers in d'Appolito)) with a similar setup very effectively, but prefer the Heresy sound.

Even very few floorstanders reach down clean to 20Hz.

So you don't care if the speakers have a unacceptable timbre as long as the have a flat graph to look at? Hate to break it to you but you may want to get rid of those ears of yours.


Edited by William - 3/18/13 at 2:37pm

I would guess you would be better crossing at 80 Hz. A crossover is not a brickwall filter, so the sub will be filling in some of the power above 80 Hz.
No, the top octave (10-20 kHz) is not that important. Not much is there, and you can't hear all of it anyway.

That is the average human ear frequency response at deferent loudness levels . AKA: Fletcher-Munson curve

Every speaker system/design has it's own unique timbre quality and characteristics. For instances in general a metal tweeter may sound more metallic (cymbal like) and bright. A paper tweeter may sound more mellow and warm. As far as higher end speakers are concerned specs on paper are all but meaningless. It is strictly subjective SQ that matters. If it sounds good and accurate to you in your room then it sounds good no matter what a piece of paper says.

Don't forget this quote from the measurement discussion: "The nearfield measurement technique exaggerates the level of a speaker's output in the upper bass..."

The response is reading about 5dB hot at 102Hz in large part because of JA's measurement technique.

People say a lot of things, often without having much basis for saying them. What the Harman research indicates is that things like tweeter material are less important to listeners than frequency response.
It doesn't. For the purposes of this discussion, it's irrelevant.

I don't know, but it might. Different areas of the cone material vibrating in different modes should affect one another, since the areas are mechanically connected. The response curve shows what happens at each single frequency, but it can't show what happens during music if cone movements are not simply the sums of the movements produced by each component frequency taken separately.

This is not how an audio system works. The "summation" happens long before the signal reaches the drivers. A wire can only carry one frequency at a time, and if you think about it, neither can your ears. Your eardrum is either going in or going out, and it can't be going in (or out) at two rates at once.

I guess you must be thinking of fundamental frequency. We want speakers to handle more than fundamentals. Look up "Fourier analysis", sometime.

Obviously, if you want speakers that are designed to meet Harman's technical criteria, you will buy speakers from Harman. Their two brands for home audio are JBL and Infinity. At the low end of the price range they have speakers like the Infinity Primus P163 6 1/2" 2-way at under $100 and at the high end they have Revel. There is a ton of product in-between. Many of them sound very good when I listen to them.

If you are interested in looking at speaker measurements, I will agree with the other favorable comments about Stereophile and add a link to this web page: http://www.soundstageav.com/speakermeasurements.html

You may find these pages particularly interesting:

http://www.stereophile.com/content/paradigm-reference-studio-20-v5-loudspeaker

http://www.soundstagemagazine.com/measurements/paradigm_studio20_v3/

Long story short - this is a fine choice, depending on your requirements, It must be used with a good subwoofer for best results.

Most modern speakers are designed to be used with subwoofers, probably crossed over around 80 Hz.

Speakers have 4 more-or-less independent properties:

(1) On-axis frequency response
(2) Off axis frequency response or directivity
(3) Distortion
(4) Dynamic range.

In particular ribbon speakers tend to differ from dome tweeters related to items 1 & 2. Actually, a long ribbon acts something like a long row of small cone or dome tweeters.

Off axis response can have a strong secondary effect on sound quality. If a speaker is directional, it does not cover the whole room equally well with sound at all frequencies and sound quality will fall off quickly outside of the speaker's sweet spot. However, by not showering the entire room with sound, the room's acoustics are less significant.

Seems like.

Looking at potential SPL versus frequency from that 7" cone I get:

Freq,Hz Max SPL, DB

10 70
20 82
30 90
40 95
50 98
60 102
70 104
80 107
90 109
100 110
110 112
120 114
130 115
140 116
150 117

Which tells me that crossovers in the 80-100 range should work out pretty well for a high end system.

They claim 1/2" Xmax which gives the following potential:

15"

Freq,Hz Max SPL, DB

10 84
20 96
30 103
40 108
50 112
60 115
70 117
80 120
90 122
100 124
110 125
120 127

18"

Freq,Hz Max SPL, DB

10 89
20 101
30 108
40 113
50 117
60 120
70 123
80 125
90 127
100 129
110 131


These speaker's have drivers that are about 50% SOTA in terms of linear travel. Really good subwoofer drivers this size have about twice the linear stroke and run $350 or more a piece. That's why SOTA subs often run over $2k .

Hold that thought! One reason why we need eq is that the rooms affect the performance of speakers so much.
Edited by arnyk - 3/19/13 at 7:32am