RBH Sound SX-6300/R Tower Speaker Measurements and Analysis
Impedance / Phase Measurements of the RBH Sound SX-6300/R Loudspeaker System
Above left are the impedance plots of the HF/MF section (red), the LF section (blue) and the entire system (black) of RBH Sound SX-6300/R review sample. Above right are the system impedance plots for
both speakers.
At the LF end of each system impedance plot we find a local minimum of just under 4Ω at 36 Hz, located between the two impedance peaks that are typical for a vented system. The frequency of this local minimum is a good indicator of the woofer/cabinet system tuning frequency.
At just under 530 Hz we find the review sample’s global impedance minimum of 3.2Ω. Based on this minimum the system can be loosely described as having a nominal impedance of 4Ω. 3.2 Ω is swinging pretty low, impedance-wise but at this 530 Hz minimum the impedance is almost purely resistive (1.2˚), so any competent solid state power amp should be able to handle the speakers impedance load. Having said that, If you enjoy listening at realistic playback levels, then heed RBH’s recommendation and power the SX-6300/Rs with an amp rated at 100W – 300W.
At right are the system impedance curves for both review samples. Presenting them in this way allows
for a quick comparison. Essentially, the closer the impedance plots match, the better. In this case, the curves closely resemble each other and indicate better quality control, system to system, and better matched performance between the speakers. The impedance moduli present no signs of any major mechanical or acoustical pathologies (e.g. panel resonances) being reflected back into the electrical domain.
RBH Sound SX-6300/R system amplitude response, 1m, on-axis, ~2.828 Vac (left); system amplitude response at 0˚ (Blue), 15˚ (Dark red), 30˚ (Purple), 45˚ (Gray), and 60˚ (Black) off-axis (right) normalized to the on-axis response plot. All plots 1/12 oct. smoothed for visual clarity.
Above left is the amplitude response plot of the SX-6300/R. All measurements were done outdoors. Measured sensitivity was 88 dB (averaged 300Hz – 3kHz, 2.828V/1m). On the right are dB spl amplitude response plots for the system on-axis (0˚ (on-axis); 15˚, 30˚, 45˚ & 60˚ off-axis, 200Hz – 20kHz.
The dips in response at ~ 1 & 3kHz are visually more obvious than they were sonically. The dip at 3 kHz is particularly not concerning. Why? At around 3 kHz our hearing is somewhat less sensitive to diffuse sound. Recording mics, on the other hand, are usually flat, response-wise, even when operating within a diffuse sound field. On playback there is perceived more energy in the 3kHz range than would have been the case had you been at the actual recording location. Given that (and the fact that the human auditory system is less sensitive to dips than to peaks) and all in all the sonic impression they left were minimal. The peak seen at around 115 Hz manifested itself mainly when listening to male voices, such as a radio DJ, where it would add a bit of midbass warmth to the speaker’s voice. Otherwise it didn’t seem to detract from the systems performance, even when listening to recordings of unamplified instruments (chamber music, harpsichords, etc).
Left: dBr comparison of both SX-3600/Rs amplitude response loudspeakers when measured 1m, on-axis, ~2.828 Vac. At right: dBr comparison of the system response with and without the grill cover.
The SX-6300/Rs had a remarkable ability to keep images within its soundstage rock solid to a degree that’s not often encountered in less than stratospherically-priced loudspeaker systems. Comparing the amplitude response of both speakers (top, left graph) offers one explanation for this particular talent. Essentially the amplitude response of one speaker was normalized to that of the other. Any differences would then show up as a value other than zero dBr. As can be seen by the plot the two systems matched very, very well. Excellent!
At right above is another dBr comparison, this time of the amplitude response of the system with and without the grill cover. If the grill cover had absolutely no effect on the system’s amplitude response, the dBr plot would be a straight as an arrow. In this case we see a great deal of variance in the 2 – 10 kHz range. Accordingly, all critical listening was done with the grill covers removed.
See also:
It's too bad RBH only sells to the little audio shops.
They list 3 shops within 100miles of me, none are convenient by any means.
Last time I tried to find one, they were closed! Owner works "bankers hours"!
It seems like everything i purchase these days has to be shipped to me!
It's too bad they don't sell any of the upgraded products through their EMP site.
These look VERY similar to the RBH manufactured EMP E55Ti...
As a former owner of the EMP EF30T and current owner of the EMP E55Ti; I'd be interested to get some opinions on how these compare.
While they have a similar driver compliment, the EMP's don't compare to the RBH SX/R series of speaker. The EMP's are fine speakers for the money, but the RBH's are in a different league. The RBH's use a Scan Speak 9500 series tweeter which is arguably one of the best soft dome tweeters ever made. The driver cost alone is about $150 per tweeter. The RBH's use cast baskets with vented pole pieces and much higher excursion woofers than the EMPs.
I've spent years listening to RBH and EMP products and while they share some of the tonal characteristics of each other, RBH proves you get what you pay for!
I'll see if I can get a pic up later.
I would prefer to go grill-less but my dog's tail would whip right through one of those woofers.
It's worth noting that the RBH line has thicker fiberboard and very likely more robust construction all around. Though, I can't say I've found the construction of their internet direct EMP line up to be lacking.
My big question is whether or not those upgraded drivers are really worth a $2800 price difference! The bass performance is probably better, but I cross over the E55Ti's @ 60hz anyway. The sub should do better with anything below that. (TC LMS-R 15"/Crown XLS2000/20hz tuned port)
Is that a Piano black finish on your system? It looks pretty nice!