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RBH Sound I-12/e Sound Quality & Performance Tests

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The majority of the listening tests done with the RBH I-12/e subwoofer was with music.  In the Audioholics Showcase family room system I compared it directly to two JL Audio e112's, which I know is an unfair comparison considering the 6X cost difference of JL subs and dual subs always being better than a single sub.  However, it was a good gauge to what I am familiar with in that room setup.

Armin  Fourplay

CD: Armin Van Buuren - Mirage
I fired up the title track "Mirage" to give the I-12/e a workout.  The room was pumping with deep tight bass.  As I cranked it up, the I-12/e held its composure well.  There was good weight to the bass, especially with 1 port plugged to increase the very low frequency output.  For comparative purposes I switched over to my dual JL Audio e112's.  There was really no comparison, the JL Audio's managed to muster up more tactile feel, and better overall quality of bass, which wasn't surprising given the cost difference and also comparing dual subs to a single sub.  However, I still respected what the RBH sub was able to do in my large room.  It provided very satisfying bass output for bass heavy music like this.  I never heard it strain or run into gross distortion, which was a testament to the well-engineered driver and limiter circuit in the amp.  Track #5 "I Don't Own You" had the 12" driver pumping really well in the RBH sub.  Thanks to the flat linear output above 80Hz, the sub blended in seamlessly with my satellite speakers allowing them to sound like a full range speaker instead of a sub/sat system. 

The I-12/e belted out clean tight bass without complaining.

CD: Best of Fourplay
I like using this CD to test bass since some of the tracks really let you stress a woofer that simply can't handle a loud kickdrum.  Track #5 "The Chant" has been known to misalign a few voice coils in my theater room on wimpy designed woofers.  I cued this track up first and cranked up the volume.  The RBH I-12/e had no complaints.  It belted out clean tight bass without complaining.  I was particularly impressed with the seamless integration I was hearing between the sub and my satellite speakers.  I found a good blend to convince myself I was listening to a full range system instead of a sub/sat system.   Track #7 "Bali Run" showcased the wonderful bass playing of Nathan East.  It was a very satisfying experience to hear fulfilling bass round out the sound of my system at listening levels I'd be a bit embarrassed to admit I was enjoying in the comforts of my home while the wife and children were out. 

Dark Knight Rises Blu-rayBlu-ray: Dark Knight Rises
Say what you want about Christian Bale, but in my book he was the best live action Batman to date. Dark Knight Rises doesn't disappoint when it comes to action, and especially sound. The opening scene with the giant plane pulling and ripping apart the passenger plane is pretty epic.  The I-12/e handled the deep bass without complaint. It may not have been as visceral an experience as my reference subs, but the end result was clean bass that gave plenty of heft to make you appreciate the scene.  I found the sub sounded cleanest with one port plugged which is what I'd recommend when listening to program material with very deep sustained bass.  My favorite bass moment in this film is when the Batwing takes off to flee the police force.  In my reference theater room the bass from my Status 8T's reference speakers (RBH's top model), makes your spinal column shake.  That is bass below audibility and very difficult to reproduce on all but the very best subwoofers properly set up in the room.  The I-12/e makes a valiant effort of recreating this effect and unless I hadn't experienced it on my reference system, I'd never know anything was missing.

There are 3 tuning modes for the I-12/e subwoofer as shown below in a screenshot from their manual.

RBH Port Tuning

RBH I-12/e System Tuning

RBH I-12/e sweeps

Outdoor 2 meter ground plane testing of the RBH I-12e

The I-12e exhibited a very linear frequency response beyond 100Hz making it a good subwoofer for small satellite speakers requiring a higher than 80Hz crossover frequency.  The limiting factor for output of this sub above 20Hz was actually the amplifier, which wouldn't allow me to exceed 103dB output levels at 2 meter as seen above for continuous sweep tests.  I couldn't help wonder how much more output this sub would have if RBH chose an amplifier with a less aggressive limiter and how that would have ultimately affected my listening test results.

For max output, you will want to leave all 3 ports open.  However, if you want extended deep output and slightly more control below 20Hz, I'd recommend using 1 port plugged.  Trace #6 shows the woofer losing control below tuning with all ports open but plugging 1 port dampened and lowered this behavior to subsonic frequencies.

 RBH I-12/e tuning

RBH I-12/e System Tuning

Tuning with all ports opened was around 21Hz but with 1 port plugged, it dropped to about 18Hz.  You do loose about 1-2dB of efficiency with one port plugged but in my opinion it's worth it for the increased extended low frequency response and better system control below tuning.  

CEA2010 Test Results

Here are the peak CEA2010 burst results taken at 1m and translated to 2 meter in the data table below.  The mic was SPL calibrated with a B&K 4230 reference microphone calibrator.

Frequency 3 Ports 2 Ports
20 Hz 93.2 dB 100.3 dB
25 Hz 107.6 dB 107.0 dB
31.5 Hz 110.6 dB 107.1 dB
40 Hz 112.0 dB 109.3 dB
50 Hz 109.9 dB 109.9 dB
63 Hz 109.2 dB 109.5 dB
80 Hz 109.5 dB 110.2 dB
100 Hz 106.2 dB 106.1 dB

CEA 2010 Results 2 meter rms (measured sideways)

 25Hz 2port  31.5Hz 2 Port  40Hz 2 Port

CEA Distortion Thresholds (2 Port Mode)

Large Bassaholic

Based on the test results above, the I-12/e has earned our Large Bassaholics rating, signifying that it should be able to provide satisfying bass levels in rooms of 3,000 cubic feet to 5,000 cubic feet (read about our Bassaholics room rating system). If you can afford it, I would still go for multiple subwoofers, regardless of room size, for the sake of smoothing out the low-frequency response and extending dynamic range. 

 

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Recent Forum Posts:

Rick Ross posts on January 17, 2017 20:14
Some problems I have with Gene's review. In the video, he stated he would probably do testing from 2M, obviosuly due to the port and driver orientation. Then in the actual review it was done at 1M. As has been mentioned, this can kind of “short change” a sub with ports on one side and driver on the other.

Then, to further add to the unfair treatment of the I-12/e, it's compared to dual JL E112's, which are around $1800/each. What in the world is this all about? Would have made MUCH more sense to compare it to a single, comparable sub like the PB-2000 or HSU VTF-2 MK5. That's like comparing a Chevy Malibu to a Corvette ZR1 that has even been heavily modified.

I can also attest to the outdoor numbers, from the questionable testing method, don't reflect the same in room. I have the I-12/e and can say the difference in 3 port to 2 port output at 20Hz does not drop off so steeply in 3 port mode. The difference is actually very minimal. The sub with the ports reinforced by the wall keep the output much stronger than the over 7dB drop from the max burst test.

Finally, how this sub only get 4/5 stars in this price range for fit/finish and build quality is hard to fathom. The I-12/e is easily 5 stars in these categories for this price range. One of the best looking, well built subs you can get for less than $700. Needless to say, a lot of this review doesn't reflect the true character of this sub.
shadyJ posts on January 09, 2017 18:10
One more thing I want to add is the I-12/e wouldn't be an easy subwoofer to fairly measure with respect to some other subs in its class because its ports on the opposite side of its driver. I am not a hundred percent sure of the method used to measure it, ie the sub's orientation, any type of compensation used, or the environment and mic positioning, -these things will all affect the test results- but if the tester just placed the mic 2 meters in front of the driver and ran the bursts and the long term sweeps, that type of testing puts this sub at a disadvantage in port-generated sound. This can knock off a significant amount of dB measured in deep frequencies. The I-12/e may just be a bit more potent in-room than what is shown the measurements in this review.

The problem of measuring subwoofers that have ports or passive radiators on different sides than the driver can be mitigated a bit by placing the mic further away from the subwoofer, so the extra output that the mic gets from being closer to the driver is reduced by closing the distance gap from the ports. Another thing that can be done is using a sub with a single point of acoustic emission, ie. a sealed sub with one driver, testing it outdoors to establish a reference point for its performance, and then placing it indoors and running the same tests. This establishes a compensation curve that can be used for further indoor testing with other subwoofers. By doing this, the total output of any sub from all points of acoustic emission, no matter where they are on the subwoofer, can be more fairly measured.
shadyJ posts on January 08, 2017 22:56
nickboros, post: 1164935, member: 19021
Nice review Gene. I agree with your assessment that RBH might want to be a little less aggressive with the limiter on this sub. The direct competition for this subwoofer seem to be the Hsu VTF-2 mk5 and the SVS PB 2000. If the RBH sub can eek out about 3 dB more without significantly increasing the distortion, then it is pretty comparable to the Hsu sub. While the Hsu sub is cheaper, the RBH looks much better. I would definitely spend the extra money on the RBH sub for the nicer looking finish, if the performance between the two are quite close. If the performance of the Hsu it a bit better in terms of raw output, then the extra cost of the RBH becomes a tougher sell. Also of note, the price of the RBH sub is very close to the SVS PB or PC 2000, which has a lot more output, that is clean. But, it doesn't have port tuning capabilities. I am only comparing these two subs to the RBH subwoofer, since they were recently reviewed and measured on Audioholics.

Yet another comparable subwoofer would be the Rythmik LVX12, that also has port tuning capabilities and is quite close to the price. The finish isn't as as nice as on the RBH, but I think it has more output and has servo technology in the sub. This leads me to believe that the Rythmik might just be a better sub in a least a couple of performance areas. The subwoofer market is a competitive market right now. This is excellent for us thinking about purchasing subwoofers, since each year the subs that we could get per dollar is getting better and better and sometimes there are even more budget friendly options like the RBH that also look great.
Not much is known about the LVX12, so I am not sure why you would think it would have more output. The I/12-e is not doing badly in this area. In many frequencies it is neck-to-neck with the subs you mentioned in burst testing. The standard I-12 looks to be an interesting value proposition since that extra 150 watts isn't likely to amount to much more than 1 dB difference, yet it is $200 less expensive.

As for the limiter, on a sub like this it has to be aggressive because there isn't a way for the sub to know how many ports are plugged. If RBH had a way to adjust the amplifier to know how many ports are plugged, they could better optimize the performance for those operating modes (let's see that feature on a mk2 model, RBH!)

Another thing, that nice gloss finish is not likely to be cheap. If you wanted to beef up performance and keep the same price, something has to give. Hsu made this trade-off going from the VTF-2 mk4 to the mk5, they discarded the satin black for a black vinyl finish.
nickboros posts on January 04, 2017 12:56
Nice review Gene. I agree with your assessment that RBH might want to be a little less aggressive with the limiter on this sub. The direct competition for this subwoofer seem to be the Hsu VTF-2 mk5 and the SVS PB 2000. If the RBH sub can eek out about 3 dB more without significantly increasing the distortion, then it is pretty comparable to the Hsu sub. While the Hsu sub is cheaper, the RBH looks much better. I would definitely spend the extra money on the RBH sub for the nicer looking finish, if the performance between the two are quite close. If the performance of the Hsu it a bit better in terms of raw output, then the extra cost of the RBH becomes a tougher sell. Also of note, the price of the RBH sub is very close to the SVS PB or PC 2000, which has a lot more output, that is clean. But, it doesn't have port tuning capabilities. I am only comparing these two subs to the RBH subwoofer, since they were recently reviewed and measured on Audioholics.

Yet another comparable subwoofer would be the Rythmik LVX12, that also has port tuning capabilities and is quite close to the price. The finish isn't as as nice as on the RBH, but I think it has more output and has servo technology in the sub. This leads me to believe that the Rythmik might just be a better sub in a least a couple of performance areas. The subwoofer market is a competitive market right now. This is excellent for us thinking about purchasing subwoofers, since each year the subs that we could get per dollar is getting better and better and sometimes there are even more budget friendly options like the RBH that also look great.
gene posts on January 03, 2017 02:21
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