simultaneously rejoice in the sudden addition of deep bass to your music and the continuance of domestic harmony. The Equipment

Size: px

Start display at page:

Download "simultaneously rejoice in the sudden addition of deep bass to your music and the continuance of domestic harmony. The Equipment"

Ada Hancock
5 years ago
Views:

ON TEST Sunfire XTEQ 8 subwoofer Many audiophiles, for reasons of domestic harmony, are obliged to listen to smaller loudspeakers than they d like, which means that although they can usually enjoy

Those same audiophiles, again for reasons of domestic harmony, are also unable to add a large subwoofer in order to deliver that bass.

1 ON TEST Sunfire XTEQ 8 subwoofer Many audiophiles, for reasons of domestic harmony, are obliged to listen to smaller loudspeakers than they d like, which means that although they can usually enjoy superb midrange and treble, they miss out partially or almost completely on deep bass. Those same audiophiles, again for reasons of domestic harmony, are also unable to add a large subwoofer in order to deliver that bass. If this sounds like your situation, help is at hand, because for US manufacturer Sunfire has come to the rescue with its XTEQ 8 subwoofer, which is so tiny that you ll be able to sneak it into the room under your jumper, install it by hiding it from sight under a chair or behind your equipment rack and then simultaneously rejoice in the sudden addition of deep bass to your music and the continuance of domestic harmony. The Equipment Sunfire is able to claim an amplifier power rating of 1,800 watts for the tiny XTEQ 8 subwoofer far more power than would be possible if it used a conventional Class- AB amplifier and quite possibly, even a Class-D amplifier because it uses an unusual tracking down-converter amplifier developed by the famous US designer Bob Carver, who founded Sunfire. But why would you want a 1,800-watt amplifier inside a subwoofer? The answer to that is partly physics and partly marketing. In order to extract good low-frequency extension, low distortion, and high volume levels from a subwoofer, you need a large enclosure. The problem is that very few consumers want large enclosures in their living spaces. So manufacturers build enclosures that are smaller than optimum, and whenever they do this, they have to compromise by making a choice between reducing low-frequency extension, increasing distortion, or lowering maximum volume levels: in other words, something s gotta give! However, there is a work-around to getting bass out of a small cabinet, and it s one that hinges around the fact that one reason the volume drops off when a cone is mounted in a small enclosure is that the amplifier has to work harder to push that cone, which requires more power lots more power. In the past, it was not practical to include a sufficiently high-powered amplifier in small subwoofers they simply cost too much to build. But Carver s tracking down-converter amplifier was the first one to break the rules: it could deliver enormous amounts of power 24 Australian Hi-Fi

very cost-effectively, and it was this that enabled Sunfire to build such small subwoofers and this new Sunfire XTEQ 8 is certainly small indeed at just 267 315 270mm (HWD) it s the smallest model in

2 very cost-effectively, and it was this that enabled Sunfire to build such small subwoofers and this new Sunfire XTEQ 8 is certainly small indeed at just mm (HWD) it s the smallest model in the XTEQ range. (There are two larger models, the XTEQ 10 and XTEQ 12.) As with all products Sunfire builds, the model numbers of the XTEQ 8 actually mean something. The XT stands for extended The circuit will automatically adjust the frequency response of the subwoofer for the best performance in your room Throw, because the roll-surrounds fitted to the drivers in these models have Sunfire s so-called Asymmetrical Cardioid Surround geometry, which the company says: enables them to travel over a very long throw without distorting. The EQ stands for Equalisation, except that in this case, the equalisation is automated. Each subwoofer comes with its own microphone and has a signal generator and measurement circuitry built in that can be used to measure the output of the subwoofer in your room, after which it can then automatically adjust the frequency response of the subwoofer for best performance in that room. It does this at four frequencies: 35Hz, 49Hz, 64Hz and 84Hz. (And if, for any reason, you don t like the result of the automated circuitry, you can over-ride it, and instead set the equalisation by ear.) There have been several improvements to Sunfire s automatic equalisation circuitry over the years it s been available, the most significant of which is to my mind that this latest iteration is by far the easiest and the fastest to use. However, another significant improvement was the switch from analogue to digital circuitry, which made the calibrations and equalisation more precise. As for the final number in the model name the 8 that s good ol imperial inches, showing that the XTEQ 8 has an 8-inch (203mm) diameter bass driver. And yes, that s driver singular there is only the one driver, and it s on the left side of the subwoofer as you re looking at it from the front. The circular thing that looks like a driver on the opposite side to the woofer (that is, on the right side of the subwoofer as you re looking A rotary control is used to adjust crossover frequency, and is adjustable from 30Hz to 100Hz, plus there s a Bypass setting at the extreme clockwise setting of the control. The phase control also rotary is continuously adjustable between 0 and 180. The level control is rotary, with calibration markings only for Min, 0dB and Max. There are several fittings for use with the automatic equalisation circuitry, including an EQ LED, a Start button, an EQ on/off switch and a microphone input. The other controls are a 12V d.c. trigger for remote power switching, a power LED and a mains power switch. at it from the front) is actually a passive radiator that is, although it has a cone and suspension, it does not have a voice coil or a magnet: its motion comes about entirely in response to air pressure variations inside the cabinet caused by the movement of the other side-firing bass driver: which is the reason some people call passive radiators drone cones. (They re also known as auxiliary bass radiators, or ABRs). Whatever you decide to call them, Sunfire is at least honest enough to point out that it is a passive radiator: Some manufacturers don t mention it at all, presumably hoping you ll think you re getting multiple drivers. The rear panel of the Sunfire XTEQ 8 has both unbalanced (via RCA) and balanced (via XLR) inputs as well as two line-level outputs. The line-level outputs can be a simple pass-through (unaffected by any of the subwoofer s settings) or high-passed through an 85Hz high-pass filter, using a switch located between the left and right output terminals. There s also Slave Input and Slave Output terminals, which allow you to link multiple XTEQ 8 subwoofers together. By using the Slave links to do this, all the settings you make on the Master subwoofer will be replicated on the Slave subwoofers, which greatly simplifies operation if you are using two or more subwoofers. Using dual subwoofers is a classic way to solve issues you may have with room modes, plus it s also an easy, efficient, and cost-effective way of increasing bass levels in larger rooms. A rotary control is used to adjust crossover frequency, and is adjustable from 30Hz to 100Hz, plus there s a Bypass setting at the extreme clockwise setting of the control. The phase control also rotary is continuously adjustable between 0 and 180. The level control is rotary, with calibration markings only for Min, 0dB and Max. There are several fittings for use with the automatic equalisation circuitry, including an EQ LED, a Start button, an EQ on/off switch and a microphone input. The other controls are a 12V d.c. trigger for remote power switching, a power LED and a mains power switch. Although the mains power switch has only two positions (off and on) the XTEQ 8 is fitted with a signal-sensing circuit that will turn the subwoofer off after a period of time during which it does not detect an audio signal. If you then apply an audio signal, it will switch on automatically. (I prefer three-position power switches Off, On, Auto but for no particular reason it s just an idiosyncratic personal preference.) In Use and Performance When it comes to getting the ultimate performance from a subwoofer it is essential that Continued on page 56 Australian Hi-Fi 25

3 ON TEST Continued from page 25 you position it in the optimum acoustic position in your room before you do anything proved to me that despite its small size, the Toccata and Fugue in D Minor (BWV 565) else at all. Sunfire s manual has excellent Sunfire XTEQ 8 is easily the equal of many advice, but for perfect placement, follow the larger subwoofers, and it was able to reproduce the very lowest notes in the audible instructions here: spectrum. Sure, it wasn t able to do this at Sunfire s manual also contains excellent quite the same volume level as I recall being advice about how to best set the crossover, able to achieve when I reviewed the XTEQ volume and phase controls, but you ll get far 12, but it was still able to play the lowest better performance if you take a more technical approach to tuning, using the system high volume levels and, thanks to the use notes it was able to reproduce at surprisingly outlined here: /sub of a passive radiator rather than a bass reflex Using the tuning approach outlined in the port, there were no unwanted chuffing link will require a small financial outlay of sounds, as there can be when driving a bass around $30 (for an app for your phone and reflex subwoofer at high volume levels. a test CD) but I guarantee the results will be However, since almost all the bass you worth it. hear when listening to music actually falls You will also need to calibrate the XTEQ 8 between 30Hz and 100Hz, this is the region using its own automated calibration routine, in which you want a subwoofer to deliver its which is as simple as positioning the supplied microphone in the listening position, was happy to oblige in this respect, delivering best performance, and the Sunfire XTEQ 8 pressing the EQ Start button and waiting a very uniform response across this frequency around seconds, after which the job band, with a very pure tonality, so that the is complete. For best performance, I would notes it reproduced had a very musical sound recommend running the automatic equalisation process BEFORE you do your external overtones. Distortion was also very low. quality, with no unwanted harmonics or calibration. One problem with small subwoofers is As is my custom, the very first thing I their tendency to move along your floor played was Jean Guillou playing the great when they re delivering low bass at high levels, though frankly the XTEQ 8 is so heavy (it organ in the St Eustache church in Paris (Dorian DOR-90134). The playback of Bach s weighs 19.4kg!) that the fact it could possibly Tech Talk: The Tracking Down Converter Amplifier The tracking down converter amplifier is a variant of the Class-H amplifier topology, and to understand how Class-H works, you need to understand that in amplifiers that use conventional power supplies, the designer uses a power supply with a voltage high enough to deliver the maximum power the amplifier is capable of delivering. So, for example, if the amplifier were to be rated at 100-watts per channel into 4Ω, the power supply would need to deliver 20 volts (P=V2/R so 50 = 400/4). The problem is that when the amplifier is not operating at its maximum output, and instead is delivering, say, only 1-watt, which requires only 2 volts, the power supply will still be delivering 20 volts, so the remaining 18-volts is wasted (it s dissipated as heat). This isn t a problem with low-powered amplifiers, but as power output increases, the cost of building power supplies for them becomes prohibitively high, and it also becomes difficult and expensive to remove the increased heat that results from the increase in power (no matter whether you remove this heat using heat sinks, cooling fans or a combination of both). In Class-H designs the voltage of the power supply is varied depending on the power output required at any given moment, so that if you re playing at 1-watt, it would supply only 2-volts, since this is all that s required. Then, when you turned the volume up to 4-watts, the power supply voltage increases to 4-volts. At an output of 50-watts, the power supply would deliver the full 20-volts. This means there s no waste, very little heat (so no need for heatsinks and fans) and importantly that the power supply can be made relatively cheaply. The difficulty in designing Class-H designs lies in the designer ensuring that the power supply always stays one step ahead of the output stage, otherwise it won t be able to deliver the voltage required at the precise instant it s required. Carver s tracking down-converter was a innovative way of doing this inexpensively and with very few components indeed it was sufficiently innovative that he was awarded a patent for it US Patent #4,484,150. (Carver s patent application cites more than thirty previous patents outlining previous similar approaches to the problem, so he didn t invent Class-H, but he did invent a unique and very practical implementation of it: one that s been so successful that it s still being used four decades later, often in preference to Class-D.) # move at all is testament to the power of the driver it contains. Nonetheless, to prevent this happening the four feet underneath it have what Sunfire calls an Anti-Walking Tread Design. I have absolutely no idea how this is supposed to work, but I can say that it must, because my review sample stayed exactly where I positioned it throughout the auditioning sessions, and did so when I tried it in other rooms with different floor surfaces. (Carpet, wood and tile, if you re interested.) Conclusion Size (both cabinet volume and driver diameter) certainly helps when it comes to subwoofer performance but, as I explained at the start of this review, today s technologies enable many workarounds that make it possible to extract big bass from small subwoofers. However, once you are using these technologies to level the playing field as Sunfire is doing with its XTEQ series the fact remains that the subwoofers with the larger cabinets and the bigger bass drivers will still deliver more and deeper bass than the smaller ones. The only thing you won t be able to do with the big ones is hide them from sight, whereas you can do this very easily with the XTEQ 8. So my conclusion must be that if you have a smaller room and are desirous of deep bass and domestic harmony Sunfire s tiny XTEQ 8 would be a great choice. greg borrowman Readers interested in a full technical appraisal of the performance of the Sunfire XTEQ 8 Subwoofer should continue on and read the LABORATORY REPORT published on page 57. Contact details Brand: Sunfire Model: XTEQ 8 Category: Powered Subwoofer RRP: $2,499 Warranty: Two Years Distributor: Qualifi Pty Ltd Address: 24 Lionel Road Mt Waverley VIC 3149 TF: T2: (03) E: info@qualifi.com.au W: Tiny! Sophisticated Sensational bass Max volume limit Deep bass extension Limited colour choice 56 Australian Hi-Fi

LAB REPORT Laboratory Test Results Graph 1 shows the in-room frequency response of the Sunfire XTEQ 8 subwoofer for four different settings of the crossover.

In these modes, the Sunfire XTEQ 8 s response was measured as being 30Hz to 140Hz ±3dB. With the crossover set to Normal (65Hz), shown by the blue trace, the Sunfire s response was 28Hz to 95Hz ±3dB.

These are all very close to Sunfire s specification, which claims 22Hz 100Hz but I can t say how close because Sunfire doesn t state whether the two figures in its spec represent 3dB down-points or

4 LAB REPORT Laboratory Test Results Graph 1 shows the in-room frequency response of the Sunfire XTEQ 8 subwoofer for four different settings of the crossover. The traces show that the response in Bypass mode (black trace) is almost identical to the response with the crossover control set to 100Hz (red trace). In these modes, the Sunfire XTEQ 8 s response was measured as being 30Hz to 140Hz ±3dB. With the crossover set to Normal (65Hz), shown by the blue trace, the Sunfire s response was 28Hz to 95Hz ±3dB. With the crossover set to the minimum position (30Hz) the Sunfire s response was measured as 27Hz to 100Hz ±3dB. These are all very close to Sunfire s specification, which claims 22Hz 100Hz but I can t say how close because Sunfire doesn t state whether the two figures in its spec represent 3dB down-points or 6dB down-points (or some other db level entirely). Graph 2 shows the results of near-field testing on the XTEQ 8, where the outputs of the driven cone and the auxiliary bass radiator have been measured separately for the same four settings of the crossover control. All traces show an increase in bass extension over the far-field in-room responses, with the Normal trace being 6dB at 20Hz, which shows that optimally positioning the XTEQ 8 in a room will Figure 1. Far-field frequency response. Bypass x/o (black trace); 100Hz x/o (red trace); Normal/65Hz x/o (Blue trace); Minimum/30Hz x/o (Green trace). Sunfire XTEQ 8 Subwoofer. Figure 2. Nearfield low-frequency responses. Bypass x/o Setting (Driver: Light blue solid trace; ABR dashed blue trace); Normal/65Hz x/o Setting (Driver: Black trace; ABR dashed black trace); Minimum/30Hz x/o Setting (Driver: Red trace; ABR dashed red trace). Sunfire XTEQ 8 Subwoofer dbspl Hz Graph 1. Far-field frequency response. Bypass x/o (black trace); 100Hz x/o (red trace); dbspl result in greater low frequency extension than shown in Graph 1. The output of the auxiliary bass radiator is fairly peaky, so that it gives maximum output at around 38Hz. Its output rolls off fairly quickly below this frequency, but above it, if you choose higher settings of the crossover control, it delivers appreciable output out to around 70Hz that would help augment the output of the driver. Newport Test Labs Newport Test Labs Hz Overall, the Sunfire XTEQ 8 demonstrated excellent linearity and extension in Newport Test Labs tests. Steve Holding Readers should note that the results mentioned in the report, tabulated in performance charts and/or displayed using graphs and/or photographs should be construed as applying only to the specific sample tested. There are three XTEQ subwoofers in Sunfire s range, and all are pictured here to indicate comparative cabinet and woofer sizes, with the XTEQ 8 at the far left, the XTEQ 10 in the middle and the XTEQ 12 at the right. Australian Hi-Fi 57

Emit M30 Loudspeakers Bel Canto eone DAC2.

Ampliﬁer Lavardin IT Integrated Ampliﬁer Elac

son HP1 Mitchell & Johnes.au $9.99 www.avhub.

Head WE REVIEW T DYNAUDIO S NEWESD CE RI

Yes, you can read some of our reviews in full

You can now swipe your way through every page

tablet, (or computer) using our snazzy Digital

But there s nothing like the proper print

shiny cellophane, ready for you to read at

HI-FI New Subscription or Mr Mrs Miss R!

Your Name 14 ISSUES (2 YEARS) $109 SAVE OVER

INCLUDES HOME CINEMA & HI-FI LIVING SPECIAL

SUBSCRIPTIONS PO BOX 3355 ST LEONARDS NSW 1590

for $ E-mail Please provide phone or email in

SYDNEY (02) 9901 6111 TOLLFREE 1300 361 146 Mr

5 SUBSCRIBE ANDSAVE! AND SAVE! xxx lab report LAB REPORT REVIEWED Dynaudio Emit M30 Loudspeakers Bel Canto eone DAC2.7 DAC/Preamp Parasound Halo Integrated Ampliﬁer Lavardin IT Integrated Ampliﬁer Elac Debut B6 Loudspeakers September/October 2016 son HP1 Mitchell & Johnes.au $ Headphon ca ATH-SR5BT Audio-Techniphon es Head WE REVIEW T DYNAUDIO S NEWESD CE RI BUDGET-P FLOORSTANDERS! Yes, you can read some of our reviews in full on AVHub.com.au. You can now swipe your way through every page of Australian Hi-Fi on your ipad or Android tablet, (or computer) using our snazzy Digital Issues. But there s nothing like the proper print edition, landing in your letterbox sealed in shiny cellophane, ready for you to read at your leisure, at full size, in the order we intended, in the bath, if you like. Get every issue of Australian Hi-Fi the way it should be. YES! PLEASE SEND ME A SUBSCRIPTION TO AUSTRALIAN HI-FI New Subscription or Mr Mrs Miss R! SUBSCRIPTION OFFE I A HI-F WIN Gift Subscription SYS TEM VALUED AT $5,440! Extend Subscription or Ms 8/19/2016 2:16:31 PM Your Name 14 ISSUES (2 YEARS) $109 SAVE OVER $30 7 ISSUES (1 YEAR) $59 SAVE OVER 15% INCLUDES HOME CINEMA & HI-FI LIVING SPECIAL EACH YEAR W MYMAGAZINES.COM.AU d 1 AHF Sep16_001 Cover.ind Your Address Postcode Daytime Phone ( ) SUBSCRIPTIONS PO BOX 3355 ST LEONARDS NSW 1590 PAYMENT DETAILS I enclose a cheque/money order for $ Please provide phone or in case of delivery issues IF A GIFT SUBSCRIPTION SYDNEY (02) TOLLFREE Mr Mrs Miss Ms payable to Next Media Pty Ltd OR Charge my credit card: Mastercard Visa American Express Recipient s Name Recipient s Address Daytime Phone ( ) Name on Card Expiry Date / CVV: Cardholder s Signature Terms and conditions: Price offer available to Australian and NZ residents only and expires 18/12/16. All prices include GST. Savings based on total cover price. Overseas Airmail 14 issues A$195 or 7 issues A$99. Australian Hi-Fi subscription comprises of 7 issues PA 6 regular issues and 1 special issue. Subscriptions commence with the next available issue. Please allow 6-8 weeks for delivery of your first magazine. This form may be used as a Tax Invoice. nextmedia Pty Limited ABN Please tick if you do not wish to receive special offers or information from nextmedia or its partners For full Privacy Notice, refer to If you would prefer to receive your communication electronically, please ensure we have your current hi-fi address.85 via mail Australian Hi-Fi Australian MA/HF611 Postcode

Opera Mezza Loudspeakers ON TEST. The Equipment The Mezza 2012 is the smallest speaker in Opera s Classica series. And when I say small,

Opera Mezza Loudspeakers ON TEST. The Equipment The Mezza 2012 is the smallest speaker in Opera s Classica series. And when I say small, ON TEST Opera Mezza 2012 I love that this Italian manufacturer called its company Opera to start with, but even more loved the fact that all its speakers take their names either from famous opera singers