B&W ASW 610XP Subwoofer Review

B&W; ASW 610XP Subwoofer Introduction

Bowers & Wilkins, otherwise widely known by the shortened version B&W, was founded in 1966 in Sussex England in the back of an electronics shop and just recently celebrated its 45^th year of operation. Known primarily for producing fine floorstanding speakers utilizing many innovative developments such as: Matrix bracing, modular enclosures, diamond tweeters, kevlar driver cones and the statement Nautilus loudspeaker, B&W has steadily developed over the past 45 years into what is now a loudspeaker manufacturer with global reach. Their product range has expanded into markets as varied as: OEM automotive, recording studios, pc audio, headphones and Ipod docking stations. The product that we will look at today is the top of the line subwoofer from their 600 series, the ASW 610XP, which is a sealed system utilizing a 10” driver and a built in 500 watt class D amplifier.

Unpacking and Initial Thoughts

When the ASW 610XP arrived I immediately noted how small and light the box was. Opening the box and starting to unpack revealed well thought out and implemented packaging with thick protections at the top, bottom and also corners of the sub. Contained in the box is: The subwoofer, grill, owners manual, warranty card, power cord, and an accessory pack containing a choice of either spikes or white plastic feet, both of which thread into the bottom of the enclosure.

The ASW 610XP is tiny! At 12.8”x12.8”x14.8” it occupies barely 1.4 cubic feet of volume in a room and weighs a mere 34lbs. The ASW 610XP takes the title of smallest and lightest subwoofer I have ever tested away from the Klipsch SW-311 that was reviewed here a short time ago. The finish is the first of its kind that I have seen on a speaker. It is a dark gray color which is called matte black by B&W. It has an almost rubbery or tacky texture to it. Sort of like the rubber that you might encounter on some iPod or cell phone cases. It is soft to the touch and creates a lot of traction or surface friction. I really like the finish but the one thing that I noted about it is that any moisture will leave visible marks on the finish that do not just wipe off. Even having some oil on the skin of your hands when you move the sub will produce this. You might think “Why would I be touching it or moving it more than once or twice?”, or that you don’t plan to sit drinks on it and that is probably true but it was something that I noted. Either way it is a different finish from the usual. This is one sub that will be very easy to find a place for or move when needed and it easily ace’s the test for spousal acceptance factor.

Design Overview

B&W’s ASW 610XP is a sealed design with a 10” forward firing driver and a 500 watt rated class D amplifier. There is internal EQ used to extend the deep bass response of the subwoofer and a couple of different presets available to tailor the response to suit the room or the listener preference. The plate amplifier has RCA type unbalanced connections as well as speaker level connections. There is also a 12v trigger input. There is no option to send a signal from the ASW 610XP further down the line to other equipment.

 After popping off the trim ring, which covers the frame and mounting screws for the 10” driver employed in the ASW 610XP, so that it could be removed from the cabinet, I could see that it is a rather high quality unit. B&W lists the cone as a Kevlar, paper pulp and resin mixture. The surround is a rubber half roll and the frame is a very open, six spoke, cast aluminum design with an oddly shaped mounting flange. The driver makes use of 2 generously sized spiders separated by a plastic spacer. The cone also has venting underneath of the dust cap. The motor utilizes a single roughly 6” diameter, 1” thick ferrite magnet sandwiched between the top plate and the back plate. The back plate is moderately bumped to provide voice coil clearance and features a large 2” diameter pole vent with 3 smaller vents which are probably for the gap. The voice coil appears to be a 3” nominal diameter and the leads are sewn into the top spider. This unit exhibits very nice parts quality and attention to design.

    

The amplifier for the ASW 610XP is rated at 500 watts and is listed as class D. It occupies virtually the entire back panel of the enclosure and has controls for most of the functions found on a typical powered subwoofer: Phase, gain, low pass, auto/on/standby, etc…Plus a few extras, namely the switches to control the EQ contour and extension settings. When I removed the amplifier from the enclosure I noted that the amplifier has a sealed chassis and also has its own sub-enclosure within the main enclosure. I did not take the extra step of removing the chassis cover from the amplifier to get internal pictures of the amplifier components and circuit layout. During the review process and measurements session I would occasionally check the amplifier to see how hot it was getting and it never seemed to get much more than warm to the touch throughout.

Construction of the ASW 610XP’s enclosure appears to be ¾” MDF. There is a large window brace in the center of the enclosure that appears to double as a brace for the motor of the driver and also a full panel further back in the cabinet to separate a chamber for the amplifier. There is dampening foam on top, bottom and both side walls internally. There is also a large chunk of poly fill directly behind the driver. All of this combined with the very small enclosure panel sizes results in a very inert and dead enclosure. The driver and amplifier are both flush mounted. The driver has a trim ring which snaps in over top of the mounting flange. Overall parts quality, build quality and attention to detail are very high.

B&W; ASW 610XP Subwoofer Listening Session

For all of the listening sessions the ASW 610XP was placed in the front right corner of the room firing back into the corner about 6 inches from the wall. I have determined this to be the best available single subwoofer placement in the room for most units. Audyssey was run on the system to allow it to integrate the ASW 610XP, which was then followed by a check and recalibration of the subwoofer and speaker levels prior to the listening sessions.

Blu-ray: Foo Fighters: Live at Wembley Stadium

This concert disc has been in my collection for awhile and I have watched it quite a few times so I am familiar with it. The listening session was started off with the master volume at -20 on my Onkyo receiver. For the first couple of songs the volume was left at this level and the ASW 610XP did a convincing job of reproducing the underpinnings of Taylor Hawkins drum kit and Dave Grohl’s bass tone in the rather difficult room. I could discern the weight and notes of bass lines and the kick drum had the proper thump and heft. At about the time that the band launched into “Learn to Fly” I upped the master volume to -15 to see how the ASW 610XP would keep pace with the increased demands placed on it. It responded with an appropriate increase in volume while maintaining its fidelity. Nice. Eventually I advanced the master volume to -12 at the beginning of “All My Life”. At this level I did start to notice some rounding off of the kick drum and the loudest parts of the bass range and overall limiting of bass dynamics. Still all in all the ASW 610XP delivered a pretty good performance for a very tiny subwoofer.

Blu-ray: X-Men Origins - Wolverine

I selected Wolverine in order to check out the ASW 610XP’s performance with the demanding bass of a modern movie. This film has very deep bass in parts, many dynamic bass scenes and plenty of background thumps and ominous rumbles to get an idea of a subwoofers home theater performance. In other words how deep the subwoofer can go, how much output headroom it has and how it responds to huge bass dynamics. It should come as no surprise that the ASW 610XP could not deliver big home theater impact in a room larger than 4,000 cubic feet. I had expected that this would be the case. It is a single 10” driver in a very small sealed alignment after all. Time and time again whenever there were big bass transients during the movie they were rather muted and flat sounding. Some examples are the exploding cards that Gambit throws at Wolverine in the New Orleans club, or when the cooling tower at the nuclear plant collapses. The ASW 610XP simply did not have the impact or depth with these scenes that other larger subwoofers can impart. I suspect that the ASW 610XP was being driven to the limit much of the time during the action sequences during this movie. To B&W’s credit despite this subwoofer being asked too much of it, it never made bad distress noises. It started to sound warm or muddled but did not produce anything overtly offensive. The limiting and protections on this sub work very effectively.

B&W; ASW 610XP Subwoofer Measurements and Analysis

The B&W ASW 610XP subwoofer was measured outdoors sitting on the ground with the microphone placed 2 meters from the front lip of the cabinet pointing at the main driver which was forward firing. The low pass filter was disabled and the subwoofer volume was set to maximum for all testing, except for those tests purposely conducted to examine the effects of the built in functions.

The overall approach to this testing along with the equipment and software used is outlined in the article here.

Powered Subwoofer Testing Outline and Procedures Overview

B&W ASW 610XP: Effect of Low Pass Filter Settings

A measurement was taken of the ASW 610XP with the low pass crossover bypassed using the LFE input and at maximum, middle and minimum settings to observe its effect on the response shape. This is presented in the graph above. The middle, 12 o’clock setting of the crossover resulted in a very low XO point of roughly 30Hz. The minimum setting produced what appeared to be a 25Hz XO point which is of little use. Most of the effectiveness of the control is in the top 50% of the knobs rotation. There was little difference between the response with the low pass filter bypassed and with it at maximum.

B&W ASW 610XP: Effect of Extension and EQ Settings on the Response

Above are the measurements of the effects of the ASW 610XP’s extension and EQ settings. With the 2 EQ curves and the three extension settings there are a total of 6 combinations. The results of each combination to the overall response are relatively modest and mostly consist of a slight boosting of the 30-80Hz region, or extending and boosting the low bass below 30Hz.

B&W ASW 610XP: Basic Frequency Response as Tested

For the rest of the measurements I settled on using the ASW 610XP with the extension on the C setting and the EQ on the A setting. This provides a response that is rolled off towards the low end but should lower the power demands on the amplifier due to less total EQ boost being applied and should allow the subwoofer to use more of its upper range headroom for some of the tests before becoming limited in the low frequencies. In this configuration the response is within +/-3dB from 27-200Hz. This is very close to B&W’s spec of 25-140Hz +/-3dB. The flattest combination was with the A EQ and A extension settings. In that configuration the ASW 610XP was within a +/-3dB window from 20-200Hz easily exceeding spec. These response shapes are at the base starting drive level used for testing which is referenced to 90dB at 2 meters from the microphone at 50Hz. At higher levels the output will compress and the response shape  deviates. 

 B&W ASW 610XP: Waterfall Decay

B&W ASW 610XP: Group Delay

The waterfall and group delay plots for the ASW 610XP are very good and show little to no delayed energy and certainly nothing that would be audible. The group delay never exceeds one cycle.

 

 B&W ASW 610XP: Long Term Power Compression

The results of the long term power compression sweeps show that the ASW 610XP maintains good linearity up through the 95dB nominal sweep level. During the 100dB sweep there is some compression apparent near 20Hz. During the 105dB sweep the output is being limited severely everywhere below 45Hz.

B&W ASW 610XP: Power Compression Magnitude

Looking at the amount of compression exhibited only it can be seen that the ASW 610XP does very well above 45Hz all of the way up to and through the 105db nominal sweep level. There is a large amount of compression evident on the 100 and 105dB sweeps in the deep bass. The centering of the compression at about 20Hz is an indicator that this is likely to be the center point of the built in EQ used to flatten the ASW 610XP’s response.

 B&W ASW 610XP: Maximum Long Term Output Level

The maximum long term output achieved by the ASW 610XP during the power compression testing is at the low end of all subwoofers that have been measured up to this point. Over a significant range from 24-53Hz it has the lowest maximum output recorded. The resulting response shape of the 105dB nominal sweep fits within a +/-5dB window from 30-120Hz.

 B&W ASW 610XP: 100, 105dB Sweep THD Comparison

The ASW 610XP distortion results during the 2 highest level power compression sweeps are shown above. Overall this is not a bad showing. The behavior is best above 35Hz where it remains well below 10% THD. Below 30Hz the distortion starts to increase rapidly which is not uncommon. With a single 10” driver in a sealed alignment there won’t be enough sub 30Hz output to be of note anyway.

B&W ASW 610XP: CEA2010 2 meter Groundplane RMS Results

B&W ASW 610XP: CEA2010 2 Meter Groundplane RMS Comparison

CEA2010 Results

The CEA2010 maximum passing results for the ASW 610XP show that the design is amplifier limited at the 40Hz band and above. From 20-31.5Hz it is distortion limited and would produce a bit more output if distortion levels are ignored completely. At 20Hz the ASW 610XP could produce a passing result of only 85.1dB. Below 20Hz the ASW 610XP could not produce a passing result. The maximum CEA2010 passing output is the lowest of any subwoofer that I have measured yet at the 25, 31.5, 40 and 50Hz bands. It is very near the bottom at the rest of the 1/3^rd octave centers as well.

B&W; ASW 610XP Subwoofer Conclusion

B&W’s ASW 610XP has some of the best parts and build quality that I have seen on any subwoofer. The attention to detail and design execution are first rate and the ASW 610XP is built like tank. I am a little iffy on the finish. I loved the look and texture of it, but it seems easy to mark simply by touching it. Also the pint sized B&W did very well in many performance metrics including the group delay, upper range extension, and response flatness when kept at a reasonable volume level. It could easily be crossed over as high as 170Hz.

The main limitation of the ASW 610XP is that it just does not have a lot of output. It simply is incapable of delivering loud home theater dynamics in a room such as mine. I don’t want to sound like a broken record here but output and deep bass headroom is casualty number one when making a subwoofer this small and at barely 1.4cu ft external, I’d call the ASW 610XP down right miniature. Case in point I literally tucked the ASW 610XP under one arm to carry it out onto the test site. Yes there is more to a subwoofer or any speaker than sheer output obviously, but at some point that does come into consideration, like with home theater playback in a large room for example. You might think that I’m lambasting the ASW 610XP here. I’m not. This is more of a general comment on tiny subwoofers not the ASW 610XP in particular. Any subwoofer this size with a single 10” driver is going to have difficulties providing adequate output for serious home theater playback in anything other than a small room or near field. It’s the simple physics of the situation. The ASW 610XP has output commensurate with a subwoofer of this size and design.

What the ASW 610XP does do well is just about everything else other than dish rattling and couch shaking. It sounds great with music and should be an excellent match for a smaller space or crossed over to bass shy, small mains. If you must have something unobtrusive that blends in to your décor or fits into the smallest available nook, this sub will do that in spades. The ASW 610XP does carry a price tag of $1,199 but for that you do get a subwoofer that is very small, lightweight and packs seriously high quality components, with a generous warranty thrown in. As long as you aren’t pushing it too hard it also sounds excellent. I can’t really recommend the B&W ASW 610XP for you dedicated home theater bass heads out there, but it could be a good fit for those with a small condo, or apartment, or a very difficult to please spouse, those with limited placement options, without the space for a bigger subwoofer, a small two channel set-up, or a near field application. To audition this or other B&W products, locate a dealer in your area, or for more product information, contact Bowers & Wilkins

The B&W ASW 610XP receives the Audioholics Bassoholic Small room rating, which means that this sub is recommended as maintaining adequate headroom in spaces smaller than 1,500 cubic feet and/or for users who usually listen at a moderate to low volume level. For further information in how we make these recommendations see the full article here.

See: Audioholics Subwoofer Room Size Rating Protocol

B&W ASW 610XP Review
MSRP: $1,199

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The Score Card

The scoring below is based on each piece of equipment doing the duty it is designed for. The numbers are weighed heavily with respect to the individual cost of each unit, thus giving a rating roughly equal to:

Performance × Price Factor/Value = Rating

Audioholics.com note: The ratings indicated below are based on subjective listening and objective testing of the product in question. The rating scale is based on performance/value ratio. If you notice better performing products in future reviews that have lower numbers in certain areas, be aware that the value factor is most likely the culprit. Other Audioholics reviewers may rate products solely based on performance, and each reviewer has his/her own system for ratings.

Audioholics Rating Scale

• — Excellent
• — Very Good
• — Good
• — Fair
• — Poor

Metric	Rating
Bass Extension
Bass Accuracy
Build Quality
Fit and Finish
Ergonomics & Usability
Features
Dynamic Range
Performance
Value