Rel Series T/i Powered Wireless Subwoofers Preview

One of the keys to getting a lifelike sound from a sound system is getting the low frequencies right. However, the physics of low-frequency playback is, in a sense, far more demanding than that of higher frequencies. Low-frequency sound reproduction necessarily involves the movement of large volumes of air, and that is difficult to do without building a correspondingly large enclosure. This often runs into conflict with two realities of our homes: living space is precious, and we want our homes to look nice. So compromises must be made if we are to fit a sound system with true bass capability into our homes. Rel’s T/i series subwoofers make this compromise as painless as possible. They do so by their very reasonable sizes and also by being an extraordinarily nice-looking line of subwoofers.

 

The relatively modest size of the T/i subwoofers does not mean they only have a modest sound. Huge woofers aren’t absolutely needed to move lots of air; woofers of moderate size that have long throw can push a lot of air, but the engineering challenges of these kinds of designs become much more demanding. However, this engineering challenge is one that Rel has long since mastered. In addition to using long-throw drivers, the T/9i and T/7i subwoofers also use passive radiators to assist in the lowest frequencies of their operation. Passive radiators are a great way of getting deep bass from a small enclosure. They are a solution to getting the same deep bass that a vented enclosure can get but without the necessarily larger size of the cabinet and also acoustic artifacts of vents. As with everything in loudspeaker design, there are trade-offs, and the trade in using passive radiators is that they are a bit more costly than simple sealed or vented designs.

Rel has long been lauded in audiophile circles as a high-end subwoofer manufacturer. What in the T/i series merits this lofty status? Aside from the gorgeous cabinet, one unusual aspect of their design that exudes high-end is the use of true A/B amplification. Rel has to be one of the few subwoofer manufacturers that still use A/B amplifiers. Most other subwoofer manufacturers use some variant of class D amplifier that, while more efficient, introduce more opportunities for error and non-linearity than class A/B. Class A/B amplification produces a purer voltage waveform. Rel states their amps use high-current power supplies and huge toroidal transformers, and that their amplifiers are extremely reliable with very few needing repairs.

Another rare aspect of their design is the implementation of a high-level Neutrik Speakon input. Speakon-terminated cables are greatly preferred for their reliability and security over standard banana plugs or bare wire. Unlike most other subwoofer manufacturers, Rel strongly encourages the use of high-level connection over the use of the LFE input alone, for a more seamless blend with the main speakers.

Something else that separates Rel from other subwoofer manufacturers is the work they have put into their input filters.

Ultimately, what we learned was that input filter speed mattered- a lot. We had always had fairly fast filters- our old ones in classic RELs like the Studio III measured around 13-15 milliseconds of group delay (very fast compared with the American subs of the day). We wondered if could you hear it- really truly notice a difference- if they were faster and, if so, HOW fast did they have to be. The short version is "fast", noticeably more transparent, occurs at 8 milliseconds and faster.

- John Hunter, Lead Designer, and owner of Rel Acoustics

Rel also takes strenuous measures to reduce mass from the cone. Their ‘AlloyFibre’ cone composition is a combination of different paper cones that make them light yet stiff and reduces resonances. In fact, the white of the cones is not a cosmetic decision; it was done simply to avoid the weight penalty of the carbon black used to make the deep black color of traditional cones. The front of the cone is hot-pressed for a smooth texture, while the rear of the cone is hand-thrown, which, to quote John Hunter, is “naturally dried which results in a heavily textured surface that breaks up all manner of resonances while staying light.”

A nice feature of the T/i subs is protection circuit that Rel calls ‘Set-Safe’ which is always monitoring output from the amplifier. It will engage a limiter that protects the cone from over-driving at very high excursions and also prevents the amplifier to go into clipping which can also damage the driver from loss of control. There is also a thermal overload device that will shutdown the subwoofer for a five-minute cooldown time when it senses things are getting too hot.

Balanced Performance and Aesthetics

So the Rel T/i series subwoofers are feature-rich, promise good performance, look great, and doesn’t eat up a lot of space; the catch is that they aren’t the least expensive subwoofers in the marketplace. However, they aren’t as expensive as you might expect. Ranging from $600 to $1,299 for the series, they are one of the few audiophile-grade products that do not require you to be a millionaire to own. Incidentally, REL tells us this series is one of their best sellers of all times which speaks volumes for how well they are received by their fans. While there are similarly priced products that offer substantially more output for the same price, they would definitely look out of place in an elegantly designed home interior. The Rel T/i subs could fit nicely with even some of the most luxurious interior decoration. They're sure to be a great choice where you want a good bass sound without sacrificing any aesthetic merit of your living space. 

If you've got a space you really want to locate one of these subs but don't have a prewire run for it, don't sweat it. You can add their compact Arrow wireless kit (MSRP: $199) to any REL T/i subwoofer to be free from the confides of a cable at no penalty in audio performance.

Unless otherwise indicated, this is a preview article for the featured product. A formal review may or may not follow in the future.