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Yamaha NS-6490 3-way Budget Speaker Review

amirm

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#1
This is a review and detailed measurements of the Yamaha NS-6490 3-way speaker. It was kindly purchased new by a member and drop shipped to me (back in spring no less!). They cost US $130 a pair on Amazon including Prime shipping. I think I found it elsewhere for just US $99 which is quite a low price for a 3-way speaker.

The pair of of NS-6490 come in a giant cardboard box because each speaker itself is far bigger than just about any bookshelf speaker you have seen:

Yamaha NS-6490 3-way bookshelf speaker stere review.jpg


Doesn't this look pretty and utterly marketable? Makes you think you are buying the famous Yamaha studio monitors with their white drivers.

Some of your dreams are dashed when you lift the speaker and notice that it is incredibly light especially for its size. Part of that has to do with very thin walls:

Yamaha NS-6490 3-way bookshelf speaker stereo back panel review.jpg


I must say, it has been decades since I have seen spring terminals on a speaker like this.

Measurements that you are about to see were performed using the Klippel Near-field Scanner (NFS). This is a robotic measurement system that analyzes the speaker all around and is able (using advanced mathematics and dual scan) to subtract room reflections (so where I measure it doesn't matter). It also measures the speaker at close distance ("near-field") which sharply reduces the impact of room noise. Both of these factors enable testing in ordinary rooms yet results that can be more accurate than an anechoic chamber. In a nutshell, the measurements show the actual sound coming out of the speaker independent of the room.

I performed over 800 measurement which resulted in error rate of slightly above 1% in the upper treble frequencies.

Temperature was 59 degrees F (yes, it is getting cold here). Measurement location is at sea level so you compute the pressure.

Measurements are compliant with latest speaker research into what can predict the speaker preference and is standardized in CEA/CTA-2034 ANSI specifications. Likewise listening tests are performed per research that shows mono listening is much more revealing of differences between speakers than stereo or multichannel.

With the offset tweeter, it was not convenient to set that as the tweeter axis. So I made the executive decision to pick a point between the mid-range and tweeter for that.

Yamaha NS-6490 Measurements
Acoustic measurements can be grouped in a way that can be perceptually analyzed to determine how good a speaker is and how it can be used in a room. This so called spinorama shows us just about everything we need to know about the speaker with respect to tonality and some flaws:

Yamaha NS-6490 3-way bookshelf speaker spinorama CEA2034 Frequency Response Measurements.png


Man, do we have flaws! Have we measured a speaker with this bad of an on-axis response? I don't remember. From what I have read, the woofer is driven direct and only an electrolytic cap is used for each of mid-range and tweeter drivers. So they all bleed into each other's range causing rising amplitude.

Narrow peaking in the response which shows up in all the upper graphs indicates resonances (something having a life of its own when activated) and we have more of them than I have ever seen. It is like having nearly a dozen little speakers turning on and off all the time.

You can see evidence of resonances just the same in impedance and phase response:

Yamaha NS-6490 3-way bookshelf speaker Impedance and Phase Measurements.png


Early reflections are flatter but not really flat:

Yamaha NS-6490 3-way bookshelf speaker spinorama CEA2034 early reflections Frequency Response ...png


Predicted in-room response shows the flaws we have already predicted:

Yamaha NS-6490 3-way bookshelf speaker spinorama CEA2034 Predicted In-room Frequency Response ...png


Beamwidth is highly variable indicative of no control:

Yamaha NS-6490 3-way bookshelf speaker horizontal beamwidth Measurements.png


Looks like my guess with respect to reference axis was correct:

Yamaha NS-6490 3-way bookshelf speaker horizontal directivity Measurements.png


Yamaha NS-6490 3-way bookshelf speaker vertical directivity Measurements.png


Distortion is high as well:

Yamaha NS-6490 3-way bookshelf speaker Distortion Measurements.png


Yamaha NS-6490 Listening Tests
Youtubers would go crazy if they tested this speaker: "wow, how detailed!" Well, it is detailed because it has hyper elevated response above a few hundred hertz. It sounds just like it measures. I brought down a number of peaks in the response and that made it somewhat reasonable to listen to. But whether it was resonances or distortion, it would still sound bright.

Power handling was good until it catastrophically was not. A loud static was heard as I pushed up the volume. You get no notice up to that point so I suggest not overamplifying this speaker.

Conclusions
If you were to throw away everything we know about how to produce a proper sounding speaker, and amped up the best marketing and industrial design you could get, you would arrive at the Yamaha NS-6490. In a showroom its bright nature will likely sound good for a a minute or two before you pull out the credit card.

Searching I see some mods online. It may be a fun project to mess with it although you won't get rid of the resonances without a lot of work and expense.

It pains me to give the Yamaha NS-6490 as it really looks good to me. But I just can't recommend it.

------------
As always, questions, comments, recommendations, etc. are welcome.

Harvesting fruits and vegetables at the scale we have was always a pain. That all changed when my wife made this lovely basket that has a leather strap you put on your shoulder:

Handmade fruit basket.jpg


You walk and put items in it. When it fills up, we transfer to a larger container. The above is the last of what was on our Apple Tree. Yesterday there was a dozen or more left. Today half were gone with some animal enjoying them instead of us. Fortunately, we have had so much of them that we don't mind sharing. Then again if it was the darn racoon that ate most of our cherries last year, I am not happy!!!

Having our helper come dig some ditches and clean up around the yard. He makes $15/hour which is twice as much as I make doing these reviews. So please help with donating what you can using: https://www.audiosciencereview.com/forum/index.php?threads/how-to-support-audio-science-review.8150/
 

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sweetchaos

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#4
Great review!

It's the only 3-way passive bookshelf under US$300 that I found.
It got released in 2003 on amazon.com, so it's amazing it's still available to purchase today!
The other bookshelf Yamaha released in the same year was Yamaha NS-333 (which strangely is out of stock, but was selling last month).
 
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amirm

amirm

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Thread Starter #5

napilopez

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#6
Yikes! Clearly from the flat power response school. I guess it's a very.. umm resonant speaker. I don't think I've ever seen a speaker with this many resonances!

This is also definitely one of those situations where you can't just look at the DI curves and call it a day. You might think you can EQ this speaker into perfection but those beam width charts make it seem like there is no hope.
 

MZKM

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#7
The tweeter’s waveguide looks very poorly designed. We know that sound likes very smooth transitions, which is why waveguides are ideally asymptotic. Also, I wonder is the vertical groove for the top screw is maybe why the vertical directivity is wider, or if it’s just in relation to the poor crossover.
At least Yamaha knows it is bright and recommends only slight toe-in in the manual.

I must say, it has been decades since I have seen spring terminals
You are forgetting the Dayton Air you measured in February.
 

stevenswall

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#9
Are there good speakers that have their drivers arranged like this, or should designs like this be categorically dismissed if they don't have a waveguide and play back with the tweeter and mid vertically aligned? (Reminds me of the Dynaudio Lyd.)
 
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#10
Great reviews. This was my first speaker a long time ago, they were on sale for $79 a pair at one of the closed down circuit city back then. They were extremely bright without any good bass, which correlates to the measurements. Nowadays they're neglected to cheap speaker stands duty in my little nephew's room lol.
 

bigjacko

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#11
This speaker looks very stylish IMO. From the horizontal dispersion graph there seems to be interference between mid and tweeter. Is it normal for this kind of design? Has someone solved this problem?
 

pavuol

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#12
Btw. on its product page there are mostly positive user reviews, one of them writed:
"I know my pair of NS-6490s are brand new and need to be played and broken in longer so hopefully the tweet will lose some of that edginess and have a little more sparkle once the capacitors get seasoned."

..waiting for @restorer-john to explain the capacitor issue :p
 

tecnogadget

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#13
Great review. Basically one of the best looking budget speaker, so much it could fool the average joe into thinking it is “real hi-fi”.

At the same time the worst case of resonances seen on any impedance and phase response chart of ASR history, beamwidth does not fall behind also being one of the worst examples ever.

Its a shame Yamaha manages to make such a great work on other areas but can not master the “budget” solutions.
 

AnalogSteph

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#14
This one needs something resembling a decent crossover, as expected... the midrange clearly plays very high, so treble dispersion becomes a dumpster fire. The number of resonances is ridiculous, I guess the baffle is not rigid enough and the cabinet is nicely resonant?

Even so, the response looks surprisingly EQable - it would still be a resonant mess but at least the tonality would be right. Power DI actually is quite even overall, if ragged. The woofer is not actually half-bad either, I bet multitone wouldn't look too terrible... the high tuning probably helps.
 

Maiky76

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#16
Hi,

Here is the EQ data.
The EQ APO config file is attached.

Spinorama no EQ:
Score: 1.6 Poor!
Yamaha NS6490 No EQ Spinorama.png

Regardless of the orientation (vertical or horizontal) better point the tweeter at the ear.

Yamaha NS6490 2D surface Directivity Contour Only Data.png

EQ Design
large deviation from flatness, I tried to tackle the worst resonances.
Is there any damping material in the enclosure?
Score: 5.05

Code:
Yamaha NS6490 APO EQ 48000Hz
October262020-152439

Preamp: -1 dB

Filter 1: ON PK Fc 374.5 Hz Gain 2.23 dB Q 1.14
Filter 2: ON PK Fc 447 Hz Gain -2.41 dB Q 2.83
Filter 3: ON PK Fc 772 Hz Gain -4.44 dB Q 1.51
Filter 4: ON PK Fc 1231 Hz Gain -2.23 dB Q 7.57
Filter 5: ON PK Fc 1564 Hz Gain -3.05 dB Q 6.31
Filter 6: ON PK Fc 2988 Hz Gain -4.83 dB Q 15
Filter 7: ON PK Fc 6390 Hz Gain -2.1 dB Q 7.29
Filter 8: ON PK Fc 4868 Hz Gain -6.38 dB Q 0.8
Filter 9: ON PK Fc 7234 Hz Gain 3.19 dB Q 3.25
Filter 10: ON PK Fc 12887 Hz Gain -7.27 dB Q 2.02
Yamaha NS6490 EQ Design.png

Corresponding Spinorama:
Yamaha NS6490 EQed Spinorama.png

Zoom PIR-LW-ON
Yamaha NS6490 Zoom PIR-LW-ON.png

Regression tonal:
Yamaha NS6490 Regression-Tonal.png

Significant improvements but still mediocre
Yamaha NS6490 Radar.png

Rest and APO config file attached
 

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mhardy6647

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#20
This speakers excites me to take out the crossover and design a whole new, active crossover.
well... and not to seem cynical or anything, but the well-worn phrase polishing a turd fairly leaps to mind vis-a-vis products like these. :(

For the record, and FWIW, I briefly had a pair of the titular Yamahas' forebears, the NS-A636 (if memory serves) -- I would have awarded them a decapitated panther a priori. The best thing I can say about them was that they were dump finds. They were terrible.

dumpyamahae
by Mark Hardy, on Flickr

The CR-220 was also a dump find -- but was (and is) not terrible. It's an adorable little "entry-level" receiver. One of the two (?!) I've acquired over the years still lives here, in fact.

EDIT: Two other Yamaha loudspeaker-related stories, if I may.

1) The three-ways above were also sold under (if memory serves) the Optimus brand by Radio Shack back in the early/mid 90s. I'd have to go back to paper catalogs to be more specific, because -- sadly -- the 'radioshackcatalogs' site has been down for at least the last few days. I do hope it's not gone for good!

2) In the mid/late 1970s, as the cost of... well... pretty much everything soared, and the energy crises (plural -- 1974 and 1978) wreaked havoc on, at least, the US economy, the Japanese manufacturers manufactured their lower cost loudspeaker products in the US (or had them manufactured there). I mention this mostly because Yamaha's entry-level product in those days, the NS-4, was... actually... a pretty good sounding loudspeaker. The price (ca. 1977) was, if memory serves, on the order of $95 each. They were little sealed box two ways with dome tweeters -- much more of a piece with the then popular US made monkey coffin loudspeakers (EPI, AR, AVID,etc. etc., etc.) than the rather abhorrent multi-way "Kabuki speakers" for which the big-name Japanese hifi makers had become known in the US. I even semi-seriously considered the NS-4 while I was saving my pennies to buy my first "modern" loudspeakers -- but I managed to get a demo pair of the Polk Audio Monitor Series Model 7A for a very good price. The 7A have served (present perfect tense!) me well for over 40 years.

1603715015191.png

(just a borrowed image from teh webz -- I don't guarantee the woofers are original in this photo, but they look, at least, about right)

1603715132152.png

(from an eBAY auction...)
 
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