RBH T-30LSE Design Overview

The RBH Sound T-30LSE system is a speaker system cut from a different cloth. It provides that "better than being there" sonic experience typically only found in unamplified live musical performance. It was born to reproduce music with unparalleled realism, free of dynamic range or bandwidth limitations. This system can go toe-to-toe sonically with some of the most expensive gear made and comfortably hold its own. With only 100 pairs being produced, you better get your dose of overindulgence before they are going going … gone.

There comes a time in life where self indulgence becomes a calling, much like a wolf is drawn to howl at the moon. Some face a mid life crisis by splurging on an exotic sports car in an effort to redefine their youth. Well I haven’t hit middle age yet, but I definitely feel my calling to self indulgence would include dumping some coin on a truly state-of-the-art speaker system.

RBH Sound is no stranger to Audioholics. In fact they are “speaker of the house” for many of our senior staff reviewers, including me. There is a reason to this madness – it’s called performance. As audioholics, we are always seeking to push the envelope of performance without breaking the bank. In this category, RBH Sound has been a shining example of what a loudspeaker company NOT driven by marketing and litigation can produce for true audiophiles.

First Impressions

When the freight truck showed up to the Audioholics Showcase home I knew I was in for some heavy lifting. What I didn’t expect was the truck driver to forget the lift gate, causing me to carry each 300lbs+ speaker (speaker packed in crates) off the truck. Luckily my neighbor, who just returned from service in Iraq, helped me carry these mammoths up my flight of steps into the primary listening room.

Standing at just over 5ft tall these speakers don’t exactly blend into a room, or carry a particularly high WAF factor. I would say they are designed for the serious audiophile who decisively creates a room specifically for sound… or is a bachelor… or both. Don’t try to convince the wife these speakers would look great next to the armoire – they won’t.

Similar in size and shape to the venerable T2-P system that we previously reviewed, the T-30LSE system takes performance to the next step by integrating everything into a single-cabinet design. There are pros and cons to this approach, which we will get to later in this review, but they look stunning as a single box.

RBH Sound is only running 100 “Limited Edition” matched pairs of this product. Since their preview at CEDIA speakers have been shipping to customers and reviewers alike. I was honored to receive the pre-production first run pair with RBH’s owner Roger Hassing’s personal signature stamped on the back. Each production pair also gets the “Special 30 year Anniversary” plaque and comes in numbered pairs.

Build Quality

RBH Aluminum Bass Drivers

There are several good reasons why RBH aluminum midrange and bass drivers excel in performance. These include careful engineering and quality control. Granted, many manufacturers use aluminum drivers these days, but all are NOT created equal. Without the proper damping (both in the cone and the surround), cone shape, motor structure, and tight manufacturing tolerances, these types of drivers can be worse than conventional paper cones.

In order for the new T-30LSE system to significantly improve upon dynamic range and bass extension, RBH decided to employee a much higher excursion sub driver than is found in the original T-2P and 1010-SEP subwoofer products. Though the surface of the driver looks similar to its predecessor, (as you can see in the picture) its motor structure (right driver) is much improved upon. As a result the magnet size has been nearly doubled while the voice coil has been beefed up, and the driver’s excursion ability is about twice that of the original driver.

RBH Aluminum Midrange Drivers

As we learned in our Signature SE/R review, RBH Sound uses voice coil formers manufactured from Kapton in both the mid and bass drivers. This greatly increases their ability to handle heat under the most demanding conditions, which minimizes power compression and distortion. The aluminum cone material is coated with a silicon-based material and the surround is made from butyl rubber to minimize ringing and resonance. This allows the cone to enter its break up mode at a frequency well above the system crossover point. These measures undertaken by RBH ensure linear performance from the drivers, allowing them to operate higher in frequency than most conventional cone drivers. The result is a more acoustically seamless blend with the tweeter.

All four of the mid drivers in the T-30LSE system were upgraded to the Status Acoustics phase plug version of the Signature 6.5” driver. The phase plug eliminates the need for a dust cap which in turn reduces cone mass, permitting extended frequency response. This also results in more airflow through the motor structure, which improves cooling and increases power handling. A phase plug also helps to reduce on-axis beaming by dispersing higher frequencies the cone is producing.

Editorial Note on Phase Plugs
Beware, many loudspeaker manufacturers use a quasi phase plug which looks like a phase plug for marketing purposes but does not physically separate from the cone of the driver. These "so called" phase plugs can do more harm than good as they provide an inconsistent surface area. They increase the mass of the cone, yielding poorer frequency response and linearity.

RBH Tweeters (ScanSpeak)

While the standard tweeter RBH uses in their Signature product (Vifa D27 series) is no slouch, I simply love the ScanSpeak upgrade. The tweeter employed in the T-30LSE system is a 4 ohm version of the venerable ScanSpeak 9500 tweeter (which is arguably one of the best tweeters ScanSpeak has ever made). This tweeter has higher power handling, lower resonant frequency (550Hz as opposed to the 1kHz of the Vifa), and better off axis response. This yields a smoother, more open and airy sound quality with less compression. Because of a longer rear chamber the ScanSpeak driver can play much lower than pretty much any 1” dome tweeter on the market. This takes the stress of producing frequencies out if its most efficient range off the midrange drivers.

The disadvantage of this tweeter is a slight reduction in efficiency and on axis high frequency response. The loudspeaker designer must reduce the overall system efficiency to compensate, causing a need for more power to achieve similar playback volume when compared to the more efficient Vifa design. Is it worth it? Yes, if you have a discerning ear, quality electronics, good room acoustics and a slightly fatter wallet. The ScanSpeak driver is nearly 4x the cost of the Vifa, one of the reasons for the moderate price differential between Signature and Signature SE/R upgraded loudspeakers. Since the T-30LSE system employs three of these drivers, system efficiency (or lack there of) becomes a moot point.

High Quality Crossovers

RBH Sound uses nothing but the best inductors, high tolerance resistors and film caps in their crossovers. Their crossovers are designed to ensure optimal performance of each driver within its audible bandwidth, guaranteeing proper phase and frequency response of the speaker system. All of the cables are 12AWG twisted pair to minimize signal loss and reduce crosstalk. The inductors are spaced apart to minimize coupling as per our Inductor Crosstalk Basics article.

Editorial Note on Capacitors
Beware, many loudspeaker companies use cheap electrolytic capacitors in series with their mid and tweeter drivers. Electrolytic capacitors are not very linear at high frequencies and thus should not be used in series for these crossover sections.

The Cabinets

The RBH cabinets are constructed of 3/4-inch HDF (high density fiber-board) which is denser and more costly than the standard MDF found in most speaker cabinets. It’s a single cabinet design with a sealed off chamber for the mid woofer / tweeter array. As can be seen in the picture, the cabinet is well braced with baffling and damped with Dacron insulation. It is also lined with high density absorption materials for the bass portion of the enclosure. The drivers and crossovers are all wired with quality 12AWG cabling.

As with all the RBH speakers we’ve reviewed, the cabinet has a very solid feel to it and makes a nice thud sound when tapped on with your knuckles. We have never had issues with RBH build quality and this product is a shining example of their no-compromise engineering and commitment to make the best constructed product within its price class.

Design Overview

Just over four years ago RBH Sound unveiled a rather unique speaker system at CES known as the Signature T-2P System. This system won our 2004 CES Best of Show award and became our reference speaker shortly thereafter. RBH Sound referred to the driver topology in the T-2P system a “truncated line array”. This system shared many of the virtues of a classic line array speaker, such as unparalleled dynamic range and seemingly infinite soundstage – characteristics responsible for producing the very lifelike sound for which these products are known. One area where the T-2P system defined itself was in its ability to provide a competently focused soundstage and excellent imaging characteristics, strengths that are NOT common in many large line array type speakers, especially those with wide front baffles like the T-2P system. The result was that this system quickly became the Audioholics reference speaker. Life was good, our Audioholic appetite was fulfilled….. until now.

RBH Sound has never been a company to rest on its laurels. Just as they’ve demonstrated in the past, it was time for them to take a successful existing speaker system and improve upon its design by employing driver and electronics technologies from their ultra high-end Status Acoustics division. Thus the Signature T-30LSE was born.

Visually the T-2P and T-30LSE appear to be very similar loudspeaker systems. Both of these systems employ a similar truncated line array driver alignment. While their driver alignments (the placement of the drivers on the front baffle) are essentially the same, this is where the similarities end.

Editorial Note on Truncated Line Arrays
A truncated line array is simply a shortened version of a traditional line array. A line array is defined as a group of omnidirectional radiating elements arrayed in a straight line. The physical size of the line array is large in relation to the wavelengths of the frequencies being produced. While the driver array of the T-30LSE is truncated (shortened), RBH prefers to refer to the alignment as a "dispersion averaging array". The array of drivers is aligned so the combination of the dispersion properties of the individual elements in the array produces a uniform average of the constructive and destructive interference between the elements.

The T-30LSE incorporates a number of design improvements which elevate the level of performance compared to the T-2P. The T-30LSE employs the same driver topology as the T-2P system but, as previously mentioned, all drivers have been upgraded to their high end Status Acoustics versions for extended dynamic range and reduced distortion.

The most noticeable aesthetic difference between the T-2P and the T-30LSE is the latter uses a single cabinet design versus the two-piece modular design of the T-2. The one-piece cabinet design of the T-30LSE allows the dual 10” subwoofers to utilize the previously unused volume of air behind the mid/woofers and tweeters. With almost 50% more subwoofer cabinet volume than the T-2P, the T-30LSE’s bass extension is deeper (flat to 18Hz) and the overall bass alignment of the system is better damped (tighter sounding). In fact, because the new woofers have such a low resonance frequency, RBH was able to employ a 6^th order tuning with fc around 18Hz while keeping the frequency response between 20 to 40Hz slightly shelved down. This makes the system compatible with most rooms and allows the installer to place the speakers closer to a back wall. The other factors which contributed to improved bass performance include a larger 4” dimpled port, designed for improved air flow, and a new extended-excursion 10-inch subwoofer (found in the new $50k/pair Status Acoustics Titus prototype speaker system).

The crossover system (brains of the speaker) for the T-30LSE has also been redesigned to allow the crossover point between the mid/woofer and tweeter for the T30LSE to be set at 2000 Hz versus 2500 Hz on the T-2P. There are no crossover components used to high-pass filter the mid/woofers or low-pass filter the subwoofers. The transition between the subwoofer and mid/woofer drivers is optimized using the natural acoustic roll-off of the drivers.

The other notable difference between the nomenclatures of the two systems, is the T-2P (“P” designating Powered) is sold as a package with the SA-400 amplifier which is used to power the subwoofer portion of the speaker. The SA-400 amplifier can be used with the T-30LSE but is sold separately.