hello everyone this is Amir from audio science review i uh just reviewed the uh powered mod
ma speaker powered monitor from adam called the a5x i've got the written review on audio science
review website but i thought i'd do a video overview of it also and uh maybe i can explain
things a little bit more this is like typical studio monitors got amplification in it it's
a bit expensive for this size speakers 500 each so a pair of these would cost a thousand dollars
one nice thing is that it has a volume control in front which a lot of pro monitors don't have and
assume that you have an upstream volume control which i do and many other people do but if you're
using them as desktop computer speakers and you don't have a preamp or some other method
of changing volume it's nice to have this and a cool little thing is that it's got a cable that
attaches the two speakers together so you can use one volume control and control the volume on both
much like other uh probe monitors you can set the sensitivity of the input and also the treble and
bass boost you can adjust i didn't adjust any of them i usually don't and left them as default the
bass and treble the sensitivity i did it just for testing on that but otherwise
everything's the same it's a very heavy speaker despite his size you can see it back here
see if i mean struggling i think it's got old school class a b
amplifiers in it a linear power supply i can tell that because the backside actually gets warm not
super hot but it gets warm um modern uh monitor the wild switch to uh class d amplifiers which
are more efficient uh drawback and a lot of them is that they hiss through the tweeter this is uh
this one does not have a hiss that i that i could detect at least with my year close to the twitter
so that's a major thing a lot of these pro monitors are not usable
from that point of view if you sit too close to them so anyway you're here to see
our fancy measurements that i generate with a Klippel near-field scanner i set it up for a
thousand measurements um and generated about a 700 i'm sorry something fell down um something like
a 700 megabyte file so heck of a lot more than somebody just sticking a microphone in front of a
analyzer unfortunately i ran into a bug after running this test for three and a half hours
i measure run the analysis too longer than it crashed and took me all day today to run
additional tests and found a bug and a simple work around and and got it done
so those of you who think my job is great uh just know that there's a lot happens behind the scenes
that you don't see that doesn't get published but the drudgery you know uh exists on that anyway
temperatures are getting warmer now which is good this is in 65 degree Fahrenheit try to keep the
temps above 60 degrees some woofers underperformed a little bit when you go below 60 degrees
um as far as uh measurements you need to tell the system where on-axis is
and for that i just eyeball where this AMT tweeter is and i set the microphone as the reference point
in the analysis software Klippel NFS lets me move that so occasionally i've done that where
i can move the axis anywhere in computational uh portion of the analysis of the measurement
um so it's not casting concrete but just know that that's the center the manual says the same thing
it says that that is the you should point the twitter at you so um we're going by what they say
um here's our response as usual we start with this solid black line and the solid black line
if you just ignore this trough in here is actually fairly even there's a tiny bit of treble boost and
a tiny bit of bass boost but otherwise a very good response but there's this v-notch in here with
just hard to take a high off of it it just stands way out and it's quite deep probably seven or
eight db in here and then a couple of resonances on each side of it where does that come from uh
pretty simple i make a measurement by sticking the microphone very close to each driver and the port
this is the woofer in red the twitter is in blue by the way ignore the fact that twitter keeps
showing this is actually the woofer response shows up even though i have the twitter the microphone
from twitter the key thing in here is the orange line the orange line we can see that is the port
this is the part of it that we want to contribute what we don't want is that it goes down here and
all of a sudden it starts to get louder and louder and louder and peaks and goes down
this is actually a resonance inside the cabinet that just if you just excite the cabinet at that
frequency and since the ports are in the front it jets out and instantly combines with the woofer
and it combines with the woofer as the woofer response is declining and it's out of phase and
because it's out of phase it actually cancels in here rather than add and you can see that
cancellation and just a massive v in here um the good news is that it's very narrow it's it's uh
the 1.1 kilohertz over here and this is one kilohertz so it's about two 300 hertz wide and
you really got to get unlucky with some musical note to hit this and as i've explained in my
last video with our hearing bandwidth we don't have a band with this sharp in here so likely
your ears averaging part of these peaks and this trough you're not hearing exactly this
trough so the graph looks worse than it is it's a problem with these ports in the front i often
see this issue i guess they put the port in front so that you can stick the speaker close to a wall
i don't know why it'd be an issue to have the speaker close to a wall with the port in the
back but people thought that oh gosh i can't do that and i gotta have three feet behind my speaker
so forces manufacturers stick important front and it exaggerates this problem
this is on top of not mitigating it there are other ways to mitigate it but this port
resonance thing seems to be with us in many places here's a waterfall chart that basically shows your
frequency response and time and uh i don't think i've ever seen resonance stand out so clearly
in here we see our troughs in here and then we see this thing just goes on like a bell that's ringing
and uh so you know we have multiple proofs we have three different measurements all point
to the same thing and support each other early reflections which is the floor and ceiling and
back wall um they're very similar to the on-axis for good or bad for good that we want
it to be similar which means that reflections won't sound different than the direct sound
bad is that that we have the v in here and we have a little bit of directivity error in here
but there's a little bit of a dip in here so uh in general if you can avoid floor bounce or if
you have it on a desk desk bounce it does you some good but really is not a major cause of concern
if you had the speaker in far field meaning stereo listening not on your desk we can model what that
response could typically look like and when we do that lo and behold what we already know shows
up again which is we have this draft in here and this is the frequency response and by the
way above 10 kilohertz it droops down because the tweeter gets very directional as far as
distortion at 86 db at one meter is actually exceptionally good um i have this 50 decibel
reference line and is well below that even in bass which is impressive now there's a trick up
his sleeve you know the reason this is so good is because the frequency response is dropping very
quickly so this speaker doesn't try to reproduce low deep bass and as a result it doesn't have
distortion shooting way up here if you turn it up distortion goes up but still i'm not seeing it go
crazy on some speakers i see this line shoot up and actually generate more distortion than that
you put in over 100 distortion and you can see the same thing as a ratio this is absolute amount of
ratio we can see that these things start to uh you know become uncomfortable anything less than 0.5
percentage in here is extremely good so you know this is a little bit above that but still very
good if we look at the beam width which means that we take a constant amplitude and and we plot what
that looks like where you get 6 db drop-off around the speaker we see that it's very well controlled
between about 900 hertz and about eight or nine killers after that the twitter starts to beam
this beam gets narrow which means that if you don't have those two uh speakers pointed at you
and you move to the left and right you're gonna see here a drop-off in extreme highs how good
your hearing is up there it's only you know but uh for to hear the best sound you really need to
have this point of that you're at your ear which means you get it over here you get this response
you still have 20 30 degrees you can go and still not lose much but above that you will
uh same plot if we plotted with the fancy color mapping we see it over here uh this
you know this is our trough that we had the port cancellation stands out otherwise this is the even
side and then you can see how it narrows down and gets much quieter uh blue colors and green colors
are rather quiet so if you you know where if you have it like straight out and you're listening
at an angle you're up here and you're losing a ton of highs so don't do that excuse me um vertical
directivity which means this was horizontal so that means we're going 180 degrees left
and right this one is going up and down and up and down actually fairly good usually we
have these two eyes in here and many times they're very close to our reference twitter line and which
means that you got to really have the speaker pointing directly at your ears here you can
go 20 degrees above 20 degrees below so for my testing i had to point it at my ear but if you
put them flat and you're a little bit above them a little bit below them still should be fine i uh
powered them up on my desk for all these powered monitors i do near field listening tests uh
basically where i'm sitting right now you can't see it but on my right here i have a spot where
i put the speaker and the sound was just fine i mean it just was low distortion clean and
it played as loud as i could tolerate and i turned things off and the reason it could get so loud
is because it's amplification is powerful it's not some cheesy little amp in there
and also it doesn't try to apply deep bass and while it gets super loud you don't feel
a sensational bass so you need a subwoofer if you want that kind of bass for computer use
typical desktop use there's plenty of bass but don't fool yourself this is not a speaker
that's going to play anything in sub bass i have a large library of those tracks when i played them
it was as if they were not there the sub bass i mean it was just very very faint sounds
so uh what does it add up to we just have one flaw there in that directivity and by the way
it was so minor that i did not try to eq it even it is so narrow i'm not sure it needs eq
anyway as i said this little peaked on each end i didn't feel that it needed any equalization
so out of box is fine but you know it's got this design error and for 500 dollars for a
you know small speaker like this um you know you're paying a premium and you sort of want
perfection so i like it i recommend it but i'm not blown away by it because of that one flaw if that
flaw wasn't there i'd say wow this is great and also the fact that it doesn't apply a deep base
but you know Adam's a company that's competently like competently designed speakers and any shows
in here so definitely recommend it uh no that doesn't have any hiss which is a big deal
and uh you now have to go and and decide whether this is uh you know something you want to buy
relative to others i certainly blows away a lot of passive speakers that by the way you need a
separate amp form and everything else uh this is all optimized to have extremely good response
okay hope you got something out of this review see you in a future one bye-bye