Bass Tips
SIDEBAR: DESCRIBING BASS PERFORMANCE
Perhaps the most prevalent bass problem is lack of pitch definition or articulation. These two terms describe the ability to hear bass as individual notes, each having an attack, a decay, and a specific pitch. You should hear the texture of the bass, whether it’s the sonorous resonance of a bowed doublebass or the unique character of a Fender Precision. Low frequencies contain a surprising amount of detail when reproduced correctly. When the bass is reproduced without pitch definition and articulation, the low end degenerates into a dull roar underlying the music. You hear low-frequency content, but it isn’t musically related to what’s going on above it. In music in which the bass plays an important rhythmic role—rock, electric blues, and some jazz—the bass guitar and kick drum seem to lag behind the rest of the music, putting a drag on the rhythm. Moreover, the kick drum is buried in the bass guitar’s sound, obscuring its musical contribution. These conditions are made worse by the common mid-fi affliction of too much bass.
Excessive bass is a constant reminder that you’re listening to reproduced music. On the other hand, if you hear too little bass, the presentation is thin, lean, threadbare, or overdamped. An overly lean presentation robs music of its rhythm and drive. Thin bass makes a doublebass sound like a cello, a cello like a viola. The rhythmically satisfying weight and impact of bass drum are reduced to shadows of themselves. However, overly lean bass is preferable to boomy bass.
Two terms related to the quantity of bass are extension or depth. Extension is how deep the bass goes—not the bass and upper bass, but the very bottom end of the audible spectrum. This is the realm of kick drum and pipe organ. All but the very best systems roll off these lowermost frequencies. Fortunately, deep extension isn’t a prerequisite to high-quality music reproduction. If the system has good bass down to about 30Hz, you don’t feel that much is missing. Pipe-organ enthusiasts, however, will want deeper extension and are willing to pay for it.
Much of music’s dynamic power—the ability to convey wide differences between loud and soft—is contained in the bass. A system or component that has excellent bass dynamics will provide a sense of sudden impact and explosive power. Bass drum will jump out; the dynamic envelope of acoustic or electric bass will be accurately conveyed, allowing the music full rhythmic expression. We call these components punchy, and use the terms impact and slam to describe good bass dynamics. A related aspect is speed, though, as applied to bass, “speed” is a misnomer. Low frequencies inherently have slower attacks than higher frequencies, making the term technically incorrect. But the musical difference between “slow” and “fast” bass is profound. A product with fast, tight, punchy bass produces much greater rhythmic precision. Although reproducing the sudden attack of a bass drum is vital, equally important is a system’s ability to reproduce a fast decay; i.e., how a note ends. The bass note shouldn’t continue after a drum whack has stopped. Many loudspeakers store energy in their mechanical structures and radiate that energy slightly after the note itself. When this happens, the bass has overhang, a condition that makes kick drum, for example, sound bloated and slow. Music in which the drummer used double bass drums is particularly revealing of bass overhang. If the two drums merge into a single sound, overhang is probably to blame. You should hear the attack and decay of each drum as distinct entities.
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From the U.K.:
REL T-7 Sub-Bass System (3-yr warranty). 200W Class A/B power amp.
15 kg. Connected to power amp, in parallel with main speakers. Extends bass down to 30 Hz!
http://rel.net/product-archive/t-7/
Features
Custom-designed 8" long-throw active down-firing drive units and 10" front-firing passive radiators
Powerful 200 watt Class A/B power amplifier
3 Separate Rotary Controls for Hi/Low Level,LFE Level, Crossover Frequency
Dedicated inputs for Hi Level (Speakon), Low Level (RCA) and 1 (RCA) each with individual volume control. Speaker level and the LFE input can be used simultaneously.
Extremely low crossover points that allow seamless "blending" with any loudspeaker
Accommodation of Dolby Digital AC3, DTS, MPEG 2 and any other digital sound format that includes a dedicated Low Frequency Effects (LFE) channel
Proprietary REL-D™ digital amplifier input provides the appropriate Impedance and grounding environment for most Class D amplifiers
9 coats of hand-rubbed piano gloss black lacquer or high gloss white
Nickel plated steel hardware throughout
Milled aluminum feet.
Specifications
Type: Passive Radiator, front-firing passive radiator, down-firing active woofer
Active Drive Unit: 8in., 200 mm long-throw, steel chassis
Passive Radiator: 10in., 254mm
Lower Frequency Response: 30Hz at -6bB in room
Input Connectors: Hi Level Neutrik Speakon, Lo Level single phono, LFE phono
Input Impedance: High Level: 150k, Low Level: 10k, .1/LFE: 10k ohms
Gain Control Range: 80 dB
Power Output: 200 Watts (RMS)
Phase Switch: Yes, 0 or 180 degrees
Amplifier Type: Class AB
Mains Input Voltage: 220-240 volts, 110-120 volts for certain markets
Dimensions (W x H x D): 12 x 13.75 x 13.75 in., (305 x 349.2 x 349.2 mm)
Net Weight: 15.4 kg
Finish: Piano Gloss Black Piano Black or High-Gloss White Lacquer
A fine effort, well worth auditioning if you want a compact sub with decent authority
For
Composed, agile and informative sound
fine build and finish
Against
It’s just a touch soft with the leading edge of notes
REL's new T-7 subwoofer is an appealing product. It's compact, decently made and not afraid to go loud.
Push the volume levels northward and it stays firmly in charge and impressively composed for one so small.
Unlike most of its rival designs, REL has chosen to go the passive radiator route with this design instead of the more commonly seen reflex port.
In theory both approaches to bass tuning should yield similar results, yet the passive radiator route allows greater scope for fine-tuning the performance. REL has made it work well in this product.
Nicely compact – yet good and bassy, too
The T-7 is essentially a 30cm cube, but the combination of 20cm downward-firing driver, a 200 watt class AB amplifier and forward-facing passive unit means the sub can deliver generous doses of low frequencies when required.
REL is particularly proud of how its products perform through their speaker level inputs, and we can understand why - the T-7 sounds bolder and more informative when wired this way. Yet, even when connected through the line-level option, the subwoofer's poise and insight stays much in evidence.
The T-7 sounds right at home, whether adding a dose of heft to the large-scale action scenes of Inception or just dialling in a firmer foundation to the likes of Kate Bush's subtle, but rather lovely, Snowflake.
Remains agile and informative
No matter the source material, the T-7 remains agile and informative, and able to deliver really low notes without fudging the bass frequencies above.
By the highest standards, the definition of the leading edge of notes is a touch soft, which robs the sound of a little punch and precision. And it's this shortcoming that stops the T-7 from storming this class.
That said, if you're looking for a smart and capable subwoofer that's also on the compact side, this REL is well worth a look.
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http://hometheaterreview.com/rel-acoustics-ltd-t-7-subwoofer-reviewed/
REL Acoustics Ltd. T-7 Subwoofer Reviewed
By: Terry London, November 9, 2012
I have been having a great time the last six months reviewing a series of what I consider reference-level two-way stand mount monitors. This had been done in the context of my smaller two-channel system setup simply for musical enjoyment. This list includes the LSA1 Statement, Reference 3A deCapo-i, and Aerial Acoustics 5B. I became interested in reviewing a pair of subwoofers that would fit in, offering a physically small footprint as well as being relatively inexpensive, compared to the above-mentioned speakers. Based on having very positive listening experiences with REL Acoustics Ltd.'s physically large reference-level subwoofers, I was motivated to contact John Paul Lizars of Sumiko Audio, which is the U.S. distributor for REL Acoustics Ltd. After telling Lizars that I was seeking a pair of subwoofers for a reference-level two-channel music system, he recommended the T-7, which has a relatively small footprint. After setting up many two-channel systems with subwoofers, it has been my experience that using a pair, instead of a single subwoofer, leads to an exponential increase of what subwoofers add to the overall sonic performance of a system.
The T-7 is designed around a front-firing eight-inch passive radiator, with a down-firing active 10-inch woofer. The internal amp is Class AB and rated at 200 watts. On the back of the T-7 are the controls for input connectors (high-level Neutrik Speakon, low-level single phono, LFE phono), phase switch (0 to 180 degrees), crossover switch (variable between 30Hz to 120Hz) and gain control (80dB). Each T-7 is supplied with a 30-foot Neutrik Speakon cable - a nice touch.
REL Acoustic believes very strongly that, in order to get the maximum performance out of its subwoofers, you should use the supplied Neutrik Speakon cable that is easily attached to your amplifier's speaker terminals, along with using REL's Neutrik connector in the back of each subwoofer. REL does not recommend that you use the output from a preamp or receiver unless this is absolutely necessary.
I experimented using both REL's cable and connector and am in complete agreement with the company's suggestions. The T-7 performed at a much higher level with the Neutrik Speakon cable, compared to using an RCA cable from my preamp to the T-7. My speculative hypothesis is, that by using the amp's speaker terminals, the flavor and tonality of your amp is passed on by the T-7 for a more seamless blend between your main speakers and the subwoofer. Finally, REL Acoustics believes that while most subwoofersemphasize the mid-bass from 50 to 90Hz, the company's subwoofers can reproduce very low frequencies (at or around 30Hz), providing the subsonics found in music or special effects in movie tracks, which produce a more natural foundation to the music.
Although there is more benefit from a subwoofer than simply the extension of the lowest bass frequencies in the sound of the system, you do in fact get more dynamics and slam with it. However, in my experience, the wonderful and special attributes that a dialed-in subwoofer can provide to a listening area are sound-staging and spatial qualities between the players within the recording. The depth, height and width of the sound stage tremendously increases. You also get stronger image density and a more three-dimensional aspect for each player. Turning off the subwoofers flattens out the soundstage, creating a more two-dimensional image.
In my acoustic space, the placement and fine-tuning of the pair of T-7 subwoofers were straightforward and rather easy to do. Each T-7 was placed 24 inches away from the front wall on the outside corner of the two monitors and 30 inches away from the side walls. The phase was set at zero. Depending on which speaker I was using, the crossover point was anywhere from 35Hz to 50Hz. The volume also was adjusted according to the sensitivity of which speaker was being used in the system.
I used the system with the pair of T-7s on to listen to Jack Jeffer's big band arrangement of "DOUF March" (Mapleshade), which was recorded in a large hall. Magnificently, the entire soundstage totally opened up and the layering and air between the players dramatically increased in a natural way. The ambience of the recording space was also delivered where it had not been evident before the subwoofers were inserted into the chain.
I wanted to see how the T-7s would perform with a more powerful and deep bass frequency, so I listened to Dr. Lonnie Smith's 3B Hammond bass pedals on the tune "A Matterapat" (Palmetto Records). The bass pedal notes pressurized my room with the type of timbres that a 3B Hammond organ is known to deliver. Again, the spatial qualities made the listening experience more enjoyable and realistic.
Finally, listening to the late, great tenor saxophonist David "Fathead" Newman and his special rendition of "Alfie" (HighNote Records), the acoustic space and location of each player blossomed with the T-7s. The bottom octave of the sextet rhythm section increasingly became bolder, enticing you to tap your toes to the beat.
High Points
• The T-7 is built to a very high physical standard. Its appearance is beautifully finished, and offers great flexibility in setup to blend seamlessly with your main speakers.
• The T-7 will enhance the musicality of any two-channel system and still deliver all the dB levels and macro dynamics if used in a home theater situation.
• The T-7 was auditioned with over five highly regarded two-way monitors. With the built-in adjustments, it was easy to dial them in.
Low Points
• In a high-end two-channel music system, a pair of T-7s will deliver a much higher level of sonic improvement, as opposed to just one subwoofer. Therefore, you must have enough room for the pair to get the greatest possible sonic benefits.
• If your main speakers do not perform at a high level across the entire frequency spectrum, the T-7 might show up this weakness in your primary transducers.
Conclusion
I was not at all surprised by the build quality, fit and finish of the REL Acoustics T-7 Subwoofer. The company proudly manufactures all of its speakers with excellent craftsmanship, regardless of the price point. It was amazing to me that REL was able to bring much of the superlative sonic performance of its reference-level subwoofers to the reasonably priced T-7 Subwoofer. It will work great in a home theater system, but my goal was to see if it would add to the musicality in a two-channel high-level system strictly for music. It wonderfully did just that, the way that I described in this review.
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