Video Creator’s Channel Erin’s Audio Corner

Hey Everybody! This Is Aaron From Aarons Audio

Corner and today I’m going to review the scar IX 12 subwoofer. This is a 12-inch subwoofer. I ordered this on Amazon prime for 50 bucks shipped to my door and dude that’s a stupid, stupid cheap price right so you got to think how much performance am I getting for that well that’s what I’m here today to show you I am using clippable products to objectively measure the excursion the still small parameters, the frequency response and the distortion parameters for this drive unit. I’ll explain to you what those results mean and provide you with a conclusion on my thoughts of the actual performance of this 50 subwoofer. If you’re new to this channel if you don’t mind please go ahead and hit the subscribe button and give me a thumbs up and or leave a comment below.

To Let Me Know What You

think about this content. I don’t generally test subwoofer drive units, but I figured nobody else is doing it. I might as well start so latch this up push the stand down good to go latch it back in place and clamp it down attaching the speaker to the stand and that way. When we start running the laser on it which you can see the little laser beam right there the laser will determine how much excursion the woofer has and through a series of calculations in the software. It will determine how much is linear excursion versus how much is more distortion excursion and yeah I’m gonna hook this up and then I’m gonna begin testing.

First Test Is The Still Small Parameters Using

the klipple LsI and the clippable LPm modules all right when I perform my testing for still small. Parameters I always take a drive unit and if it’s new I will break it in basically means that I will test it multiple times, sending it low power just to test the impedance and then I will give it a lot of power for a little while to kind of loosen up the suspension and I’ll test it again and I repeat that process over and over until I get to the point where the ts parameters are essentially the same and once I get to that point, then I continue with the rest of my testing, so what we’re going to start right now with is the ts parameters now. This is with the subwoofer wired up into a 4 ohm final nominal load not with a 1 ohm because it is capable of 4 or 1. Depending on how you configure the DVCs and we have an. Ra of 3.

6 Le Of 1.

373. The Le is really high. The inductance is is very very high for this drive unit. The FS is 30.

6 I Clocked In Mms At 136

and the manufacturer doesn’t have mms on their website. I don’t believe if they do it’s it’s hidden it’s not right up front and by that I’ll show you what I mean if I grab their product and I go to their description sorry go to their specifications. They don’t have Mms listed in here but we’re going to look at Bl 11. 9 fs 35. 4 so let me drag this back over here and get this out of my way again.

I Measured An Fs Of 30.

6 so about five hertz off of that Bl. They had 11. 9 I have 12. 4 that’s not a big huge difference.

Now The Qts Is 0.

556 vas here’s spec so if you. Want you can pause your screen? You can take a screenshot of this. These are their measured parameters However, what I will say instead of using these parameters for modeling and enclosure what you should use is a different set of parameters which is obtained from the LsR module from the clipple and what that does is it gives you the actual parameters taken while the speaker is being played. Because drive unit parameters can change when the speaker is actually being played.

So Using The Being Played Parameters Will

give you a better approximation of an ideal enclosure for when you go to model it and these are the parameters. I use to model an enclosure the one thing that the klipple. LsI module provides you that everybody is eager to know is linear excursion now that is a measure of the excursion of the drive unit based on. a distortion threshold and for subwoofers that distortion threshold is 20 percent thD and it breaks the motor and the suspension down into individual components and it will measure each of those and depending on the input of those components. You will reach that threshold that total threshold of 20 thD and doing that leaves me with a limitation at linear x max of 4.

1 Millimeters One Way Due To Inductance Variation.

If you look at the bl you can see it is 8. 2 millimeters one way and then suspension-based distortion is greater than 11. 9, so that means the suspension could actually go further than this 11. 9, but that was as far as i needed to push it in order to resolve the parameters that I’m talking about here.

These Values Ultimately Mean That Distortion Wise The

most linear throw that this subwoofer has is 4.1 millimeters one way. What do I mean by that well let’s go look at the inductance variation. This is displacement over inductance so what this means is as the voice coil is going outward or as the cone is traveling outward. The inductance is decreasing, but as the voice coil moves inward into the gap, the inductance increases.

If They Had Used Something Like

a shorting ring, they would have actually lowered this inductance probably a good bit This. I should say this inductance swing a good bit and that would have made this number higher and ultimately what that would have given them. The ability to do is claim a higher linear excursion due to the improvement there now if you want to see what the motor force looks like over excursion. You can see that the motor is actually pretty good. There is some asymmetry just just meaning that there is more of a forward or an outward inset of the voice coil in the gap and the easy way to check that is to go in here and look at the symmetry.

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So Basically What This Is Showing Us Is

that at rest the voice coil is inset by about that’s. Such an Itty-bitty number 0. 2 millimeters, which is nothing and then at full excursion measured at about 13 millimeters. It is about 0. 26 out so not much of a change there and then if we want to go and look at the suspension now.

We Can See That There Is

a difference in the outward displacement going toward the right versus the inward displacement going to the left and if you go and look at the symmetry to break that down a little bit more finally you can see. The voice coil position due to the suspension is a almost about 1. 9 millimeters outward, which means that the suspension is causing the voice coil to be lifted out of the gap about 1. 9 millimeters from its net zero, so if they could fix that they would increase that linear excursion value for the suspension, but really it’s not a big of a factor because the suspension is the least limiting factor here, but ultimately, I think what everybody really wants to know is what is the linear excursion and linear excursion is limited here to 4. 1 millimeters one way due to inductance variation and that is the maximum allowable per the 20 thd parameter.

Now You Guys Might Be Interested

in knowing what the TS parameters are at a one ohm final load. This is it but again if you’re going to model it I would probably model it. Based on what I provided you previously? Unfortunately, I didn’t have the time to do a one ohm load with the large plus cold parameters, so sorry using the Earthworks M23 microphone I measured the frequency response open air on the test stand first thing before I even show you the frequency response is. This is not at 2. 83 volts.

Im Just This Is The Number On

the left the spl is basically arbitrary. The microphone was placed near the cone in the near field, but we can see the general shape is that there is a bump right here in the mid-base region and then it kind of tapers off and gets a little bit more flat and yeah so This is your frequency response Now let’s talk about distortion. I run distortion tests at multiple output levels and the first one I start off with is 2. 83. volts because that’s pretty standard and we can see that at 2.

83 Volts, Which Is An Spl Around

86 db or so at 60 Hertz. It’s kind of in that neighborhood we are under three percent thd three percent will be noted by this negative 30 because negative 30 db relative to the fundamental is three percent distortion and then if I go up to another plus six db so so taking that 86 db and adding 6 to it so now at 92 db. We are just over the 3 distortion limit at between what is that maybe 40 to about 90 Hertz and then if we add 12 db to that 2. 83. Now we’re at about 12 plus 86 is 98.

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So At 98 Db.

At 1 meter we are almost at 10 percent. So the negative 20 db line is about 10 percent ThD. So you can see the distortion creeps up pretty quickly as you step into the into the voltages now keep in mind that this is the subwoofer measured on the stand in free air.

There Is No Enclosure Here.

So obviously there is no benefit from an enclosure providing extra air suspension inside and providing you with a little bit better low frequency response. So this is really just to give you an apples to apples representation for other tests going forward. But the bottom line.

Here Is That The Distortion Creeps Up As

you increase output that’s not really unexpected, but now you got the data to kind of understand the components of the distortion. The last test that I do for distortion testing is a multi-tone distortion and compression test which I’ll show a clip of here. Using this allows me to set thresholds that I want to define as a maximum threshold that the distortion or the compression cannot exceed and once the values do exceed that threshold, then the subwoofer test or the the drive unit test is considered failed and then the testing stops the thresholds. I’m using for this test are for compression 3DB so if the drive unit exceeds 3 db and loss of output due to power input, then the test fails.

The Other Parameter Is Negative 20 Db In

distortion, which is 10 percent distortion and the reason I chose those is because we are a little bit less receptive to distortion on the low frequency scale than we are the higher. The mid-range frequency scale, so I gave me a little bit of slack on the subwoofers here and I’ll do that for all the subwoofers going forward, but now that you know that let’s actually look at the results. This result is providing you a baseline comparison of one volt input versus another number of steps of voltage input and what you’re seeing here is compression over frequency. The compression is

Summary

Aaron from Aaron’s Audio Corner reviews the scar IX 12 subwoofer . He uses clippable products to objectively measure the excursion the still small parameters, the frequency response and the distortion parameters for this drive unit . Aaron will provide a conclusion on my thoughts of the actual performance of this 50 subwowoofer. He will also share his thoughts on the performance of the speaker. The scar IX is available on Amazon.com for $50 . For more information, visit www.apple.com/soundcorrection-correspondent/Aaron-Audio-Corner-Columnist-Aaron-Computing-Reviews-Check out the latest episode of this week’s Audio Corner. Back to the page you came from.http://www.applecorner-com/news/corner.com-Report-back-to-the-page-com-comport-report-report.com . For all the latest edition of this article by clicking here ….. Click here to read more and watch the full video