I bought 4 subwoofers and I'm absolutely not doing a DBA! Hah!
I just received shipments of 4 subwoofer drivers and they will not be going into a distributed bass array.
I'm replacing my left and right speaker stands with powering subwoofers with 2 subwoofer drivers each. I call them powering because they will be powering the 2-way monitors that will sit on top. Here's a beauty shot of the insides.
The amp has all the DSP power I could need to produce perfect speaker measurements. I wonder if JA at Stereophile would wax poetically if I priced them high enough?? 
@erik_squires ...a pittance...*yawn* Whose, so I can wire the wherewithal...
Would 3 cords be OK for just those?....Full Minimalist... |
Reading the comments about amps I think the average reader doesn't unerstand that the amps I'm using are 3 channels of amplification plus digital signal processing. While similar to the average subwoofer amp you'll find screwed onto the back of all active subwoofers the Hypex multi channel amplifiers do not have simple controls. There's no knob to set the low pass or high pass or volume. Everyth8ing is done by the crossover designer (me) with their application. In essence if you can imagine a miniDSP EQ and crossover plus several amplifiers built into a device that shares a single power cord you will have a better understanding. These amps and others like them are the heart and soul of modern active loudspeakers. |
The issue is getting smooth bass and seamless transition from sub to main speakers. Personally I've solved that issue with a combination of floor to ceiling bass traps in the corners and EQ. Others rely on multiple subs. Of course the issue of good speaker and listener placement also matter. The AM Acoustics room mode simulator is a good place to start. The reality is that subs have 2 problems. The room and the main speakers. You must blend it into both at the same time and I know of no easy way to get around measurement. The Distributed Bass Array is not to my mind easy, cheap or something everyone can implement, but it has it's fans for a reason. |
@erik_squires talking about 'air' and 'enlarged soundstage' with respect to subwoofers: "It's not about how many subs but about the sub to main speaker integration": how would you go about better 'intergration'? |
Another benefit of using a subwoofer amp (often done as 'plate amps'), and the very first reason I used mine (aside from beying ICE design, well working/sounding, powerful): The amp came with adjustable crossover frequency and volume control (unlike my other existing 'power amps'). So using it was a given; putting it NOT into the tight space (sealed) box of the sub was just gravy (more usable volume for given exterior dimensions) AND easier to acomplish. But I guess the adjustable crossover frequency is also part of most receivers; in my case, I need to select 'small' speaker first, then I can select high pass and low pass frequencies.
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@kraftwerkturbo It's a real thing. I suspect much has to do with the appropriate high pass filter though. Several a'goners who I have convinced to try raising the HP point from 40 to 80 Hz or higher have reported the improvements along those lines. I have had this happen with 1 sub. It's not about how many subs but about the sub to main speaker integration, but if you want to add subs, who am I to stop you? |
Its the 2nd post I read today that mentions "enlarged soundstage" I never brought the low frequencies in context with 'air' and 'soundstage'. Should I start thinking adding a 2nd sub (2 smaller ones instead of 1 larger)? |
@iseland "Plateamp": I moved my "plate amp'' out of the sub box into a separate housing. Its still a plate amp (components mounted on a plate), just a 'plate am in a different housing'. Given the same space for the sub, I wanted that extra volume for the driver, and it allows me to swap out amps/crossovers, or use the 'housing amp' to drive other subs. |
You might want to check out Stack Audio Auva footers for the subwoofer (without using the spikes.) and their Auva EQ footers between the monitors and bass unit. If you need to keep the monitors low, consider 50mm Soundeck Mk2 Minis Damping Feet. They are about 3mm thick. Reviews for all of these are online, but I'm speaking from extensive personal experience. I don't comment often here, Erik, but I respect your contribution to this community. Thank you. |
Hey @barts - Honestly always a conversion more than subwoofer addition. The upper crossover point will depend on how they measure in cabinet and with the upper sections in place. The advantage of subwoofer appliance is freedom of location in the room. The disadvantage is you can't go higher than 80 Hz or so. |
Please read above. This was thoroughly discussed with @audiokinesis before. |
I would not discount the vibration-cancelling effect of having back-to-back drivers properly wired. Idoing this is DIY speakers and it's very significant. If side subs won't work, you could have one facing forward and one facing backwards, keep the same footprint and get the canceling effect. Pretty significant for subs with monitors sitting on top! |
@erik_squires *L* Razz away, my pending project is a DBA....got the drivers, the materials, and connect hdwr. in hans.... Smaller 8" drivers roughly match a 15" in surface area, which would allow the Polk sub and a pair of 10" that double-duty here. *S* If I really get addicted to bass, there's 3 more descending steps available to crack plaster I don't have...*tee hee* Only thought in query is the interior horizontal braces at top and bottom, and their porting...seems to moi' that they could stand to be a tad more substantial....2x thickness, if space available... So, when will the touted book become available to the clueless Yeah, self included, no doubt...🤦♂️ |
Reason I mentioned partitioning the enclosure is, Arnie Nudell did this way back when while tweaking the crossovers to feed each woofer a slightly different signal. I won’t pretend to understand the fine points, but I can attest that the resulting bass sounds glorious. That B&W bracing job sure looks fine... It’s not that hard to do actually, draw it in CAD and take the dxf down to your local CNC shop, but I'm gonna guess you know that 🙂
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@audiokinesis - thanks so much for your detailed reply, duke! : ) - kevin |
I’m sad to learn that Verity Audio went out of business last year despite their website still being up. I must admit that while the ideas and speaker are attractive I got here in a very roundabout way. If I had had more foresight, or if I had a better budget today I’d have made something more visually coherent like the Verity models. I'd also have kept the top units sealed and therefore much smaller. Among the big desires for me in this project is to fully re-implement the 2-way crossover and have full control over the equalization. I thought about going the miniDSP route, with the Flex HTx - but my Goddess how the cable count balloons. |
I am a big fan of going fully active and have also used top notch components going with passives with great success but love the ability to fine tune with actives and overall results the best. I once owned a $7k, 25 years ago so would be much more now, pair of two way car speakers that were simply incredible as they should be. The passive crossovers looked like super high end small amps in a machined enclosure with foil caps, custom caps, very thick solid copper circuit board...yet I ended up testing then going right back to active. Of course part of that was the need for very precise tuning in the particular vehicle I had them in. I also understand your need to do what you are doing and the fun factor of doing so with the bass department, great plan, sure it will do what you need and those look like a very good deal for the price on the (sub)woofers:)
Great drivers in the monitors as well! Rick
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What is special or innovative about your design? How do you address the time alignment issue in a vertical double front-firing design? What makes you believe this is a waxing poetic, standout piece worthy of Stereophile’s attention? |
Exciting project.
As a fully active approach and using the same digital XO/DSP over the entire frequency span you’re dealing with, I certainly consider such a system to be a single x-way speaker system per channel - even when using separate subs (via the same active XO) crossed below, say, 100Hz. The main point here is that each speaker channel is treated as such through the active crossover (with on-the-fly settings adjustments via a control unit/PC/laptop from the listening position), and that you’re using a dedicated approach to both high- and low-passing (etc.) from the low frequencies on up, and not merely "latch on" active subs to an existing and not high-passed passive main speaker system - the by far most common approach.
Maintaining a fairly flat power response is an important trait, not least in the main speaker driver transitions. Using waveguides or horns this can be achieved especially well crossing over to the woofer/mids, and at a lower XO frequency compared to using direct radiating dome tweeters. I typically don’t find the latter to blend well with woofer/mids below them, not least when compared to using waveguides or horns. In the lower frequencies I always recommend placing a pair of subs symmetrically and close to the mains and coupled in stereo as a general rule, with the best case scenario being a fully active approach with high-passed mains and all. A mono’ed DBA has something else to offer, but while having an acoustically less smooth response (unless corrected with DRC) I usually prefer a dual sub setup as described.
Indeed, but this is also dependent on the type of mid-woofers used. Using high efficiency and larger diameter pro segment woofer/mids (12" on up), not least in pairs per channel, they’re turned into rockets with plenty of headroom in a domestic environment when high-passed no higher than 80-100Hz. Crossing above ~150Hz is entering the power region (up to about ~450Hz), and this is also a sensitive area with regard to placing a crossover point, I find, and how affects the lower midrange and overall uniformity of presentation here. Oh, the compromises - both here and there. |
@devinplombier - Perhaps some of the most elaborate internal bracing systems ever construed was the B&W Matrix. Definitely too much for me but also served as I think inspiration for some really elaborate DIY cabinet construction since then:
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@clio09 wrote: "I recall hearing that system in Long Beach and liked the concept. I might like to try something like that. If you don’t mind sharing, what were the dimensions of the cabinet that was used in the set-up?" The Long Beach version of the "SuperStand" was about 24" tall by 12" wide by 15" deep, base included in the height dimension but not in the others. The footprint of the base was 18" square. Some of the internal volume was devoted to an up-and-rear firing 10" coaxial driver, and some of the internal volume implied by the outer dimensions was lost to a large "notch" in the back, with the woofer mounted on the upper surface of the notch and the coaxial mounted on the lower surface of the notch. The woofer was in a sealed enclosure. The speaker atop the SuperStand was 23" tall by 12" wide by 12" deep. Link with photos in case anyone wants to see what we’re talking about; scroll down a bit for photo showing the notch: New gear from AudioKinesis and Resonessence Labs | T.H.E. SHOW 2019 - pt.AUDIO Duke |
No, the horizontal braces are well ventilated. Since the drivers are identical AND they will have the same electrical signal there is no need to isolate the cabinet spaces. Also solid bracing reduces the internal volume so would require a larger cabinet. See Troels Gravesen’s site for other ways of using ventilated bracing, and for fun look up the B&W Matrix designs.
Aesthetics. This is how they were designed to be installed. . See the back of any powered subwoofer ever made.
Not really. In truth many have suggested that turning the insides of a speaker into a kind of diffuse field that avoids coherent (i.e. flat) reflections is the way to go. At the wavelengths involved here ~ 7' I'm not concerned.
The enclosure for the amp is really to reduce the opportunity for microphonics and long term part stability. The enclosure is, again, as recommended by the manufacturer. Alternatively you can avoid using the enclosure altogether if you can guarantee a minimum of spacing between them and anything flammable.
I’m glad I could tickle your own interest. While I did opt for 2 cabinets you could also consider using only 1 woofer per cabinet and 2-way amps instead of three, perhaps giving you the ability to put a cabinet under each surround speaker as well, if you were so inclined. The drivers however are not the most expensive part of these builds. The cabinet and amps are. |
@erik_squires I know exactly what you mean. Everyone has different ideas and I've been told many times mine won't work. Or asked why I'm bothering and so on. But passion for the sport is passion and if we don't have that and a vision for the project then IME there's no joy in proceeding. So while we might not agree on exactly how to proceed that doesn't mean I don't support you in this. Hobbies are meant to be fun! |
Are your cabinets partitioned horizontally so that each driver has its own sealed enclosure? It’s hard to tell from the drawing you posted. Also, what is the rationale for the recessed amp housing compartment and wouldn’t it be preferable, generally speaking, to leave the inside back panel of the enclosure flat? That could be done simply by knocking out the amp housing, which would also provide opportunities to implement better ventilation for your amps, which will need a lot of it 🙂 Just interested in your thought process. Thanks!
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I have 4 of the RSS265HF-8 woofers sitting around doing nothing that I was going to sell. Now you have given me something to think about as I need to downsize as well. My bass array is taking up too much space since not only does it include 4 woofers, but 2 dedicated bass amps, and an active crossover. @audiokinesis I recall hearing that system in Long Beach and liked the concept. I might like to try something like that. If you don't mind sharing, what were the dimensions of the cabinet that was used in the set-up? |
@erik_squires IME for traps to really be effective they have to be mobile as the bass energy changes frequency; IOW they are impractical. I’ve watched audiophile friends of mine struggle with this issue for decades. When finally introduced to the use of the dreaded DBA they found the the bass traps far more effective. But of course to really take advantage of this the main speakers either need to be able to handle full frequency bass energy or be crossed over at a lower frequency to prevent excursion on the drivers. IMO this is one of the failings of ’full range’ drivers, since crossovers seem to be almost religiously shunned by their designers and users alike. IMO, you really don’t want to cross over a woofer much below 500 Hz if using a passive crossover. The caps required for the midrange drivers below that frequency tend to cause too much coloration. Some speaker designers try to get around this problem by not crossing over the midrange driver at all; instead placing it in a very small air tight situation to prevent excursion. IMO/IME this, in a word, sucks. It means amplifier power is being wasted as the voice coil of the midrange is being heated up by bass energy, makes for a more difficult load in the bass (increasing amplifier distortion) and also causes thermal compression. Crossing over at a higher frequency solves this issue. But if the main speakers are going to 20Hz and the room has regular dimensions standing waves will be a problem. They are 95% of the reason a person would use room correction, but if the standing wave is causing cancellation, there’s nothing room correction can do about it since the amplifier power is being cancelled at the listening position. Even if you have 1000 Watts available you can’t solve a cancellation. That is why the main speakers really should have woofers that radiate in different directions, particularly if no DBA is planned. That will reduce the tendency to generate standing waves in most rooms. In my system I use a pair of subs (which I got from Duke) since my main speakers are flat to 20Hz. Without the subs I have severe bass cancellation at the listening position. One sub is directly to the left against the wall and the other is behind and slightly to the right. I have them facing the wall rather than the room so they can take maximum advantage of the room boundary effect in the manner as Duke designed them. Using a computer you could likely optimize the radiation pattern of the woofers to prevent standing waves and hopefully come up with something attractive at the same time. It may not take that much of an angle to allow the speakers to minimize standing waves, depending on the room. Snell used to make a speaker called the model B. IMO it was superior to the model A. It employed a woofer firing at an angle towards the wall behind the speaker and was good to 22Hz according to Snell. In my old space these speakers worked extremely well but they were only 89dB. Easy load for a tube amp otherwise and easy for solid state too.
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@kevn wrote: "duke, may I ask about your sense of things, all things room and equipment equal, if you feel that a distributed bass array will still give better bass accuracy, depth and cohesion with mids and highs than what erik is working on? Or is there too little known in his particular implementation to say? Thanks much : )" In my opinion a distributed multisub system offers superior in-room bass smoothness and accuracy, and that over a wider listening area, compared with two subs located underneath the main speakers. Either can of course be equalized, and either can be used with bass trapping. In general the more bass sources located in acoustically dissimilar locations, the greater the net in-room smoothness. Bass extension in a given room depends largely on the characteristics of the individual subs. If we’re talking roughly equal dollar amounts, a single large sub will usually go deeper than multiple smaller subs. "Cohesion with mids and highs" is largely a system-integration issue, but @erik_squires’s approach of locating the subs beneath the main speakers allows him to use a higher crossover frequency and/or gentler crossover slopes than a distributed multisub system can get away with. So Erik can cross over at 300 Hz if that turns out to give him the best results. We are all constrained in some ways in what we can actually do, so we optimize within those constraints. I’m quite confident @erik_squires has made fully informed choices to get the best results (acoustically and aesthetically) given his priorities and constraints. A few years ago at T.H.E. Show in Long Beach I showed a system which had subwoofers build into the speaker stands. The woofer itself was angled at 45 degrees to reduce the force vector in the horizontal plane and thereby reduce rocking. So despite my preference for a distributed multisub system when such is practical, I’ve also done something conceptually somewhat similar to what erik is doing. Duke |
The floor to ceiling bass traps, and wall to wall traps on the floor behind the entertainment system is in large part why I can avoid doing Distributed Bass Arrays and still get excellent results. That not only tames room modes and help EQs work better but also improves speaker placement choices.
Yes. See above. Speaker placement is not something I have a lot of flexibility with so significant room treatment has been added to the listening area.
For details on the monitors see here. The subwoofer drivers are Dayton 10" RSS265HF-8.
The final design and construction is ordered from Solen.ca (tariffs and all)
Sir, are you mocking me? WTF? Let me fully answer your question below.
That is correct. A large part of the reason for this project is that I want to rethink the mid to treble crossover. I did a measurably good job with the original but having done an active 3-way center I realized just how easy doing it better would be if active. I know audiophiles for some reason think they can install a subwoofer by trial and error. Honestly mostly it turns out to be garbage they are happy with. Sorry. They cross too low and are left with too many compromises. Yes, in this case by comparison the DBA approach removes a lot of complexity assuming you use the DBA to a high enough crossover point (80Hz or so) and so has a much higher success rate than setting a single subwoofer or two by ear. I know I’ve been teasing you all by using the term subwoofer. It is true that Dayton markets this driver as a subwoofer, and for good reason. It has good output to 20 Hz and significant excursion and power handling capabilities without being completely inefficient. This driver also has another important feature:
Lets stop talking about subwoofers and talk about this project as a new 3-way speaker system. Instead of thinking of adding a subwoofer and crossing around 40-80Hz I’m now thinking 150 - 300 Hz. The determining factors are:
Generally speaking I want to cross my new woofers as high as possible while still maintaining excellent off-axis response, not something a lot of commercial speakers have. In other words, I cut them off before they start to beam. Having the woofers located under the mid-woofers means I can cross higher without fear of the ear locating them, unlike a subwoofer appliance. By crossing high (150-300Hz) I reduce the load on the mid-woofers, increasing dynamic range but also has the extremely beneficial side-effect of reducing audible distortion even while playing low. I wrote much more about picking crossover points in my blog here. |
@erik_squires Fascinating project. Many questions though. I assume your current speaker position lends itself to relatively flat uncorrected response--true? We want details! What drivers are in your monitors/subwoofers? Who is building those cabinets? I assume your crossover points will largely be by trial and error? If your plate amp is 3 way, you will be removing the crossover from your monitors, right? Thanks and good luck.
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@audiokinesis - duke, may I ask about your sense of things, all things room and equipment equal, if you feel that a distributed bass array will still give better bass accuracy, depth and cohesion with mids and highs than what erik is working on? Or is there too little known in his particular implementation to say? Thanks much : ) In friendship - kevin |
well good for you doing what works best for you ! |
Lol @erik_squires not only are you razzing the dba crowd, but also the passive speakers only crowd. Good on you for doing what works best in your setup. I recently upgraded my subs to a pair of Rythmik F8 and absolutely swear by it. Small, light weight drivers in a sealed box to pair with my sealed box monitors and a high pass filter to keep everything separated. As for isolating the monitors, Isoacoustic Orea have worked really well for my setup. We want photos when things are up and running. |
@erik_squires seems like lots of fun. Thanks for sharing. At AXPONA, SVS was demoing their surround system. Sitting down. I felt the bass in my body and it shook my clothing. Not my cup of tea as I like crystalline highs and involving midrange. Speaker and room coupling, haven’t seen your room treatments promoting lately which is important without overdoing it. |
@jc4659 It's quite likely I've seen that before and it's stuck with me. Unfortunately that (relatively) ugly plate amp is not going to want to be seen. :) |
@erik_squires Your configuration reminds me of my Verity Audio Parsifal Encores which have an additional option of being able to position the woofer module so that the driver fires forward or to the rear depending upon which sounded better in the room. Both cabinets are sloped as well. |
@scotandholly There is a lot that went into this that has to do with my aesthetics, complete lack of willingness to add more bass cabinets and wanting to take the positive experiences I had with an active center channel and bring that over to my main speakers. So, if you look at this from the perspective of "how to add more bass" this project won’t work for you. For me this checks off a lot of aesthetic and personal interest boxes. Conversely I’m not about to try to convince anyone this would work for them. Just sharing in the fun of the project. Otherwise, those who insist I need to do DBA can look at this live picture of me and sigh away.
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@audiokinesis, definitely not trying to persuade anyone, of anything. Just curious and wanting to add to the conversation. Certainly the big guys like Wilson, Magico, YG, etc. have the same approach. But digging into the weeds, I thought you guys had a better idea, idk? |
@scotandholly, I’m pretty sure @erik_squires made his design choices with eyes wide open, and I respect them. If you want to persuade him to go with a distributed multi-sub system, I guess you can try. (To avoid possible confusion I don’t use the initials "DBA" because they can also stand for "Double Bass Array", which is a very different approach.) Duke |
Not sure what you are replying to @scotandholly |
Wait what? F. Toole's third edition of Sound Reproduction promotes almost the exact opposite, does it not? Reinforcing the DBA approach by placing the bass cabinets more in line with room response, than speaker placement. What am I missing, @atmasphere , @audiokinesis , @erik_squires? |
