Thinking I need a Sub...

I have some Nola Boxers that sound awesome but some of my favorite music has some fairly deep synthesized bass. At times, I hear the driver distorting and 'doubling over' is that the term?

So, my local high-end shop sells REL subs and I like the idea. I've been thinking of the T-7 or the R-218...

Advise would be great. I have McIntosh MC-60 amps and an Audio Research LS-3...and use an NAD CD player.

Yes! If you are able, get two. Although I cannot comment on specific REL subs, I think all small monitors require subs.
My other option is to go up to a tower like the Nola Contender...I think I'd rather do this but worried it still may not be enough?
if you can swing a Nola Contender I would do that.
I'm working on some Contenders...:)
There's about a $1900 difference between a pair of Boxers and Contenders. You will not get the bass extension or room pressurization from the Contenders that you'd get from the right powered sub(s) for less than that.

Since you're hearing your Boxer woofers distorting, you'd benefit from a sub that can send a high-pass signal to the Boxers and unburden those little woofers from attempting deep bass excursions.

One subwoofer product line that comes to mind is the new JL Audio E-series subs. They start at $1500 MSRP for the E110, which is only down 3dB at 23 Hz. According to the Stereophile test measurements, the Contender is down 3dB at 50 Hz.

The cool thing for your situation is that the E-series panel can accept low level input from your preamp, run it through a 4th order crossover, and send the high pass signal back to the amp that powers your Boxers. This will make a significant improvement in the Boxers' clarity and dynamic range.

I can't imagine getting anywhere near this performance from the Contender. You may need to take 2-4 hours integrating the sub/sats, but it will be worth it. Not only will the bass be stronger, more dynamic, and more extended than what the Contender can offer, you won't be adding cabinet noise to your mains, which is just as significant for low level detail. I've yet to hear a floorstanding version of a monitor (except Wilson, Magico, & co.) that is as clean and resonance-free as the smaller, simpler, and more rigid 2-way monitor little brother.
I agree with Johnny about high passing the main speakers. There are a few subs on the market that have high pass filters built into them.

Here's a small sealed sub that does:
I have the Rel R218 mated with Cremona Ms, just the right amount of extension for my ears. My buddy has the T7, and the bass is not as refined. I'm really spinning.

Nola says the Contender extends down to 25hz. I'm not up on the technical jargon but that seems like it would be low enough?

Sorry for the noob questions.
There are good and bad to both solutions.

The larger speakers will allow a more full frequency response that may satisfy your needs. This depends on your room, your system and your preferred lessening level. The dual sub option would more likely meet your lower frequency needs but they may be more difficult to integrate into your system for a coherent balanced sound. You may end up spending even more to get the right software fix for bass integration.

I personally would go for the larger speaker if you like the NOLA sound. Then in a year or whatever, if you are still not satisfied, think about subs again.

No right or wrong here.

That's great news about the SVS SB-2000. I wasn't sure if it high-passed to the main amp, but the user guide indicates that the line out high passes at 80 Hz. That would give the Boxers lots of breathing room. Everything below the botom string of a guitar would be handled by the sub.

01-14-14: Neo-luddite I'm really spinning.

Nola says the Contender extends down to 25hz. I'm not up on the technical
jargon but that seems like it would be low enough?

I just checked the Nola website and it claims a frequency response of 35 Hz -28
Khz for the Boxers. No tolerances are given, so that 35 Hz could be 10-20 dB
down from the output at 1 KHz. The speakers could also have been positioned
for maximum room gain irrespective of imaging and clarity of the rest of the
audio spectrum. In speakers the two most often told lies are probably claimed
specs for sensitivity and bass extension. Read the Stereophile review I provided
the link for. The response curve is there to see. The bass is down -33 dB at 25
Hz, and -18dB at 35 Hz. It may be that with the right footers, a completely rigid,
masonry listening room (no suspended wood floors), and the speakers
positioned for maximum room gain, that you might be able to *hear* 35 Hz but
definitely not 25, and neither of these diminished levels at those frequencies
would begin to compare to the linear bass frequency extension offered by either
of the subwoofers Bob and I mentioned.

BTW, in response to your subject line, *everybody* needs a sub (preferably two).
I seem to change my outlook and oppinions about all this audio shtuff quite a bit. I was on the "just buy towers" kick once I got my kef xq5's and they did everything well, at least for me and in my rig. Then I had to sell them and my new speakers don't have much bass but the midrange and highs are great (subwoofer, here I come).

Johnny makes a great point that has never even crossed my mind "you won't be adding cabinet noise to your mains" and he's definately right when he said "the bass [will] be stronger, more dynamic, and more extended than what the Contender can offer [with a good sub]".

Also, you can place your boxers where they image best, and not have to worry about bass response from the boxers because your sub will pick that up.

My issue with a sub is that I couldn't get it to integrate with my monitors like I've heard it done at shows. I'm going with 2 subs next time to see if I have better results.

By the way, 2 years ago at RMAF, I heard one of the best sounding systems I've heard, even until this day, and it was in a small room with a pair of Nola Boxers and Rel (T5?) subs. The front end gear was top notch, as was the set-up including trick room treatments. Did anyone else hear this room?
Thanks so much...I appreciate this.

Is there a simple way to explain the specs you give about db loss at certain frequencies?..I think I understand but I'm not sure.

If you do go the route of subs look into the new JL's (I've not heard them yet but do use the F113). I used to use REL's and had many, many issues so my recomendation is to stay away from REL. Just my 2 cents worth.

(Dealer disclaimer)
Jump on 2!!
I also like the SVS SB2000 sub recommendation, although I'd definitely go for two subs since this is a music-based system and bass will be more evenly distributed throughout your room. SVS runs a deal on dual subs, and you can get two SB2000s for $100 less than one REL R218, and the SB2000s go down to 19Hz (-3dB) and have a more powerful amp -- probably a lot better for your synth bass stuff among other things (much better than Contenders too). And SVS offers a 45-day no-risk in-home trial. Absolute no brainer IMHO.

No matter what sub(s) you get if you go that route, you'll need to get some kind of integration software/device. I believe Velodyne still offers a decent unit that's not too pricey and can at least get you in the ballpark, or maybe even better a DSSpeaker unit that may be possible to buy used? I think pairing the SVS subs with your Boxers and integrating them properly would be a revelation. Keep us posted and best of luck.
Low Bass doesn't care about its distribution in your room as it goes where it wants, so a single sub can work very well in all but the largest rooms. Just move it around until it sounds right at your Sweet Spot. REL's idea of leaving your mains alone (high level input) simplifies things and keeps another thing out of the signal path to take advantage of your amp's tone, which is a good idea that actually works. Also, dealer opinions notwithstanding, RELs are great sounding and reliable...the models differ of course, but you can get great results from lots of 'em (I bought a used Q150e and it's better than a smaller new one I've listened to), and you can simply pay attention to the level setting to avoid using digital compression/limiting devices which are often unnecessary.
"Low Bass doesn't care about its distribution in your room as it goes where it wants, so a single sub can work very well in all but the largest rooms."

Respectfully disagree, especially for music. Low bass might not care, but your room sure does as do your ears. All else equal two subs pressure the room more evenly and can better help even out peaks/valleys within the room (3 or 4 subs even moreso). And two subs will obviously be working a lot less hard than one. Then there's also the prospect for stereo bass, but let's not go there here. Suffice it to say I'd take two good subs over one very good sub all day if that's all the budget will allow.
I agree with Karl_desch, so upgrade your speakers if you must improve your bass. There's a reason you must spend considerable bucks for a true full range. As Karl put it, "coherent balanced sound." Adding a sub may give you the low frequency you crave, but you may not get a perfectly smooth sound. If you can still find a high-end dealer with a store out there, try listening to a quality restricted LF speaker with a sub, and then listen to that brands full range entry as a comparison.

01-15-14: Kennythekey
I agree with Karl_desch, so upgrade your speakers if you must improve your bass. There's a reason you must spend considerable bucks for a true full range. As Karl put it, "coherent balanced sound." Adding a sub may give you the low frequency you crave, but you may not get a perfectly smooth sound.
Going full range "may not get a perfectly smooth sound" either, especially if you're trying to get that balance of smooth extended bass *and* optimum dispersion, soundstage, and imaging.

At least with a sub you can do several things about integrating the bass with optimally placed monitors--change the subs' gain level, change the crossover frequency, high-pass the mains or not, change the phase, and change the location. Sure, that's a lot of potential adjusting, but it also allows several bass integration options that are not possible with full-range speakers.

All speakers have a transfer function that can be visualized as a frequency response curve. For a particular input signal strength that covers the audio band (20 Hz - 20 kHz), the speaker is able to produce sound across the audio band at different strengths. Ideally, a speaker would be capable of producing the same strength sound across the entire audio band. In such a case, the frequency response curve would be a flat line. This would be a true full range speaker.

Manufacturers give a frequency response range, but they may not say how much the sound has weakened in the bass region. So a specification of 35 Hz - 20 kHz doesn't mean much, because to reach 35 Hz the sound strength may be very much weaker than at 1 kHz. The sound strength weakening can be specified in dB units. Humans perceive a 10 dB increase in sound level to be twice as loud. So if the sound at 35 Hz was 10 db weaker than at 1 kHz it would be 1/2 as loud as the sound at 1 kHz.

Typically, people want to know the -3 dB point on the lower end of the frequency response specification. Look at companies like PSB and Paradigm and you'll see that.

Hope this helps a little.

-- Bob
Thanks Bob, that does help.

Well, I bought a REL T-7...I'll get it installed and post my thoughts. I was back and forth on this but adding a sub seems to be the consensus..and the REL seemed like the best for the money. Always a gamble!


Personally, so with my ears, subs have always sounded strangely additive, but they may not have been set up properly. Or, maybe they were'nt matched correctly. So, my listening winners have consistently been coherent full range speakers. Recently, there has been one exception, and that was the Volti/Border Patrol room at RMAF 2013. The sub, was simply not there, so I was not aware of its presence, so coherent.

Regarding, "Going full range "may not get a perfectly smooth sound" either..." I completely agree with you. Not all full range speakers are created equal. This is why my advice was to listen to the different setups within the same brand of speakers. So, compare for yourself and pick your own preference. Not the easiest thing to do, but the only way I trust to evaluate.
I agree that 2 subs are the ticket. I can tellwhere the bass is coming from with just one sub. My single svs ended up dead center between my speakers and sounded best there. I've had issues with integrating a sub into my system but will try again. I have heard subs integrate seamlessly, so I know its possible.

I would think that having control over your bsss seperate from your mids and highs would actually be beneficial. So a speaker measures flat from 20hz-20khz in an anechoic (sp?) chamber, doesn't mean it's going to have that same resonse in my 11x13 room or your 20x25 room...
A single sub needs to be positioned properly to disappear...if you place it too far off in a corner or someplace you might notice it being out of the ballfield, so to speak. My setup has the sub directly behind the left speaker and since it's set to about 51hz it blends perfectly with the mains and all the aural cues for stereo come from the mains anyway when you're sitting it the sweet spot. If I had another sub with the right side speaker it would be too close to the gear rack which doesn't need any more vibration, although everything is on vibration absorbing pods and such. All of this follows natural laws of physics regarding bass rolloff which can be read in my famous white paper, "subwoofers and the tawdry overuse of them by unsophisticated boneheads overloading their rooms and being forced to use digital room correction" request, $12.95.
Neo, if you do the typical REL connection scheme (using speaker level connections), it's not going to help the bass stress on your main speakers. That's why it was suggested to buy a sub that has a built in high-pass filter.

Here's a recent review of the R-528 that has the following quote
RELs are designed to be used in augmentation mode,
which means there is no external crossover that divides the
signal into low frequencies for the subwoofer while sending
everything higher to the main speakers. This has an advantage
and a disadvantage. The advantage is no additional electronics
or cables in the signal path, which eliminates the possibility of
consequent distortion and phase anomalies. The disadvantage is
that the main speakers are still required to reproduce bass, which
in the case of most small speakers can extract a toll in terms of
a certain constriction when the going gets tough. Freeing the
mains from handling bass typically has the effect of liberating the
reproduction, increasing dynamic range, and reducing distortion.

But REL subwoofers are not necessarily designed for
speakers that are challenged with respect to dynamic range and
bass response. As the company points out in its literature, its
“products are not traditional subwoofers, but true Sub-Bass
Systems...designed to augment the performance of ‘full range’
speaker systems in order to provide linear response down to
below 12Hz [!].” If I’m reading this correctly, most mini-monitors
and other subcompact and even some compact loudspeakers
need not apply. From the description, I am inferring that REL’s
designers presuppose that their sub-bass systems—now that the
explanation is out of the way, I shall continue to refer to them as
subwoofers—will be paired with speakers of at least adequately
flat response down into the upper end of the bass range (i.e.,
70–80Hz). Although the crossover range is from 32 to 120Hz,
I’d not be inclined to use the 528SE with any speaker with a
-3dB point in its frequency response much higher than 50–60Hz.
In other words, the 528 isn’t designed to make a speaker that is
seriously thin in the upper bass and baritone region sound full.
Thanks Bob. Yeah, I understand and totally appreicate your advice. I still may need to do a crossover or buy bigger speakers. This was a start and I liked the idea of the REL piggybacking off the's seems more 'pure'.

Honestly, the music that beats up on the Boxers is pretty extreme and I kind of doubt I'll turn it up that much..

I'm probably going to try my old Klipsch KG4s to see how they do with bass....I'm curious!

Is there some possibility that my amps were causing the distortion? Am I in need of more power? How does that work?? I'm sooo new to this. I love these Macs and don't want anything different.
Bob, the sales dude said the REL will improve the bass so much overall, I'm less likely to overdrive the Boxers...does this make sense?

Neo, it makes total sense if he's trying to sell you a

You ought to ask him if you can drive a speaker harder crossed over at 80hz vs. one that is not. I could get an extra 3-4db out of my studio 10's crossed over at 80hz vs not crossed over (running full range). That 3-4db made the difference.

Wolf, where can I order your book? Lol, hilarious...
Merkel Press.
B_limo...yeah, I get it...:)

I found more reviews of REL subs last night and they really do seem to have a different philosophy. Most reviewers seem to agree that they're very good with 2 channel stuff...which is what I'm doing. No HT for me...:)


IMO, there's nothing pure about using speaker level connections. The REL is not a passive speaker, so you are combining the sonics of two amps -- your main power amp and the amp in the REL. Plus, since this configuration does nothing to relieve the stress on the main speakers total distortion generated by the speaker system stays the same. You will be muddying up whatever bass the REL can cleanly produce with your main speakers.

I can send you links to distortion measurements done at Canada's NRC of common speakers. The gist is that speakers generate much more distortion than electronics. If you can keep speaker distortion below 10% that's good; typical solid state electronics will be a fraction of 1%. Realize that distortion is a spectrum, so even before 10% the speaker is messing up the sound.

You don't need larger speakers. Wired with a crossover you'll be creating a larger speaker with the advantage that you can place the bass source where it can perform best.

I'm guessing that you'll set the volume exactly the same with or without the REL in the system.

One of the set up duties will be to match the level of the REL to that of the main speakers. In that same process you'll have to adjust the REL's low pass filter to blend with the bass roll off of the main speakers. Ideally, you'll end up with a flat frequency curve to a much lower frequency than without the REL. But, within the crossover region the poor bass production of the main speakers will still exist and will impact the bass production of the REL. Will it be as audible as without the REL? Probably not. Will it be as good as it could be? I don't think so.

As REL says, their speakers are designed for augmenting full range speakers.
Oh sure...that makes sense. I'm still feeling good about the REL. If I'm still not happy, I'll just get a good set of full range speakers.
The "total distortion remaining the same" idea from claustrophobic Canadians in the context of REL sub use means nothing. Zero. Does anybody listen to good speakers and say, "wow, if only I could remove the bottom octaves of distorted bad things in my full range-ish mains?" No, they do not. The people who know how to design great speakers make crossovers that take into account the mechanical frequency limitations of the design. The REL dudes know how to make subs, they SOUND great (if set up properly they don't "muddy up" anything), and blend brilliantly with main speakers because that's all they're doing...blending...not truncating or slicing off the low frequencies, but blending in a suplemental way that makes the owners of RELs happier, better adjusted, and somewhat better looking than most Canadians. Most...not all...
Wolf and I have a long standing disagreement on this topic. But, it appears he's fallen into my camp... Wolf's comment is completely correct about crossovers preventing the distortion produced by drivers operated out of their linear range. He just backed up my argument for using a crossover between the woofer in main speakers and a sub. Thanks, Wolf.

In reply to his question in sentence three, yes. Those that understand what's going on. That's why Richard Vandersteen supplies a high pass filter for use with his full range speakers when adding one of his subs. Professional monitor speaker designers do as well. Since the pro recording monitor industry is flush with bass management controllers and subs with bass management. Velodyne, Martin Logan and SVS understand this since they incorporate filtered outputs in their subs.

No one said that REL speakers muddy up anything. Try reading it again. The main speakers will muddy up the clean bass produced by the REL, at least within the crossover region.

All the best,
I'm not in the Bob camp, in spite of how badly he wants me there. I'm merely speaking about the actual sounds of things, and if you adjust a REL to appear at the point where the main speaker starts to lose its ability to produce much bass and the REL takes it from there (below any main "crossover region" because that is irrelevant to the REL design), it works beautifully. There is no "muddying" of the main speaker's acoustic output because the main speaker is down some serious DBs at that point and (again, based on reality) blends fine if used properly. When you state things like, "The main speakers WILL MUDDY UP the clean bass produced by the REL, at least within the crossover region" you ignore the fact that there is no crossover region at the REL High Level input, simply a frequency point where you integrate the sub to assist the mains, and, clearly, you haven't heard a well set up REL or you would know this (maybe). I know other designs work well also, because I've heard them, and I'm IN the pro recording industry.

Completely agree with Wolf_Garcia, that's exactly how REL subs work and blend with the main speakers when setup properly.
There is a crossover region (it's obviously not irrelevant) even though there is no crossover device. It's where the main speaker naturally rolls off the bass and the low pass filter of the REL has been adjusted to blend with the main speaker.
There is no "muddying" of the main speaker's acoustic output because the main speaker is down some serious DBs at that point...
This all depends on the level -- how hard the speaker is driven. Besides, -3dB or so isn't very serious.

As you've qualified your comments with "if used properly," I agree. REL speakers used as they are designed to be used can work. Unfortunately, many people (and dealers it seems) don't fully recognize (or choose to ignore) REL's design goals.

REL was designed for almost full range speakers that aren't going to be driven hard (so they won't be distorting too badly). Using bass management yields advantages with any size speakers in any situation. Choose the approach that fits your needs.
Digital bass management compression/limiting nannys are not necessarily an advantage, they're simply designed as a "catch all" remedy for components that are badly matched to a room's acoustic properties. Of course things need to be "used properly," otherwise things are simply improper, if not tawdry.

Since Bob and Wolf (both pretty convincing contributors here) are providing conflicting advice, I'd suggest that you find a good high end HT installer/retailer and do an A/B comparison with Digital Room Correction and without it. That's a simple bypass button and a very clean A/B.

You've got to find the right showroom so that the sub placement is optimized prior to room correction EQ. Then, you can decide for yourself.

For the record, I've done that in my dedicated listening room with two different pairs of subs (Rythmik and Velodyne) and in my HT room with B&W subs. The positioning of the subs in the listening room was optimized both by ear and - on a second pass - with the aid of a real time analyzer. In the theater room, the position of the subs was largely dictated by the room layout, so there was much less flexibility in optimizing location.

In all cases, room correction made a dramatic improvement - to my ear. In fact, by my reckoning, no other change to my system over the last two decades has come close. But there's a caveat.: Since Wolf's mileage seems to vary from that conclusion, be aware that yours may, too. Which is why an audition at a retailer who can do it right is probably your best bet.


As to the active/passive (distortion) debate, that's a tougher A/B since most systems (that I know of) kill the sub output entirely when you remove the active low-cut filter from the main speakers. That means you'll probably have to re-wire the system before you can compare active crossing to passive which makes the judgement more difficult IME.

I find the theoretical arguments for actively crossing a system pretty compelling, but my experience suggests that it's very much case by case dependent upon the main speakers. I've done it both ways and had good success with both - but the best results I've gotten have come from actively crossed systems. If in doubt, I'd say cross actively but would note again that YMMV.
I agree that when a room is overloaded with subwoofer bass energy resulting in crappy sound, the easiest solution to this issue is digital limiting. My point has always been that great sounding realistic and musical bass can be achieved with a single sub used properly, and since many think "more must be better" I understand why Taming Overkill With Digital Limiting/Compression has become popular. Every poster I've noticed advocating digital management has large, powerful, and often multiple subs that should utterly overwhelm the listening space without active limiting, which seems extreme, somewhat non musical, and buying a 600 hp V8 car and installing a device to disconnect 6 of the cylinders most of the time.
To clarify re: "overloading the room".

That is not - and never has been - the issue for me.

When setting up strictly by ear, I always start by attempting to level match at the x-over point. I have generally been good to within +/- 5db in that job (the most critical set-up element IMO as smooth response thru the "hand-off" is critical to seamless integration). That result is always verified by measurement after the fact (and subsequently tweaked).

The issue with the approach is generally "lumpiness" - I've always had 10+db peaks and/or nulls without EQ - despite exhaustive placement optimization efforts. Sometimes there's a somewhat excessive bass balance overall, sometimes it's a little light overall. It's never particularly smooth - as measured or (more importantly) as heard in A/B comparison with subsequently EQ'd bass.

The issue is virtually moot with bass management software. The Audyssey set-up protocol involves setting the average aggregated sub output at 75db per measurement on a bass sweep. The resulting measured on-axis FR is essentially flat across the entire range of the system. The difference between pre EQ and post EQ is not overall bass level, it's freedom of peaks and valleys in the response. The audible difference is not in overall bass level, it's in articulation through the bass and mids.

While my subs have the capability of producing much higher SPL (the 75db start point results in the gain pots being near the low end of their potential travel), the benefit here is less driver excursion and distortion. A peek at measured distortion tests will reveal VERY large values (often well north of 30%) for most subs as driver excursion (and SPL) increases, but I'll pass on the debate as to the audibility of this phenomenon. I will only note that the remaining potential clean output of the subs that is foregone by my set-up ensures that I've minimized distortion - for whatever you think that's worth.

The bottom line is: this ain't about overloading the listening room

Listen for yourself. Wolf is an experienced professional sound guy and I respect that credential, but I've always been surprised by his emphatic stated preference for non EQ'd subs. As noted, in my book this is a black and white issue, but - as also noted - I appreciate that other people's books are different from mine.

As a side note, I usually have a guitar in my hand 3 to 4 hours a day and feel pretty good about the subjective side of this evaluation as well as the measured evidence, The good news is, this is a very easy, very clean A/B testing opportunity - as long as there's a good, high-end AV place locally. IMHO, everyone who cares should satisfy themselves on this one.
There was no mention of digital bass management and bass management (analog or digital) has nothing to do with compression/limiting.

As bass management is just a crossover, it provides the same benefit that crossovers provide in main speakers. Debating the benefit is just silly. Thinking that the benefit wouldn't apply in the bass region is just silly.
Having multiple subs in a room does not imply that the room will be overwhelmed. One simply adjusts the volume on each sub accordingly.

As far as many thinking "more is better," one just needs to read the audio literature. There's no debate.
Risking redundancy (or, more to the point...being redundant!), again, to attempt to simplify MY point...I get great sound without digital EQ in MY room with a single REL. Great, natural, non lumpy sound. It's been stated that others can't get good, non lumpy (!) tone with their multiple subs without digital assistance, and I understand why. Really...I do.

For the record: Digital bass management is not "just a crossover" or a crossover at is digital limiting (or compression) of certain peak frequencies that are considered by somebody to tax woofers, or excite room nodes and standing waves. If it's NOT limiting those "undesireable" frequency peaks, what the hell IS it doing? And the statement, "A peek at measured distortion tests will reveal VERY large values (often well north of 30%) for most subs as driver excursion (and SPL) increases" is poorly stated and, as such, makes no sense unless you're more specific...the speaker fails at what point? The amp clips? Most? Some don't?...huh? I use digital and analog EQ in venues for live stuff all the time with large, extremely powerful subs so I'm not a Luddite...and I get that many home rigs need digital assistance (some of my best friends...)...I'm only emphatic about the fact that I don't need it, in my room, with my rig. And other might not either. See? Wasn't that simple? I'm not sure what guitar playing has to do with any of this, but I award Martykl an extra point for that anyway, and please don't measure the distortion of my class A tube guitar amp...I can't take it...
Hi Gentleman, It is in my exsperience of listening, Getting one JL audio top model sub is, Game over!, No, I do not own a sub, listened to most out there, the awards and reviews got my attention to hear one, a small enclosure, accurate and deep beyond belief, stunning is the word! the sub can acommadate most rooms with the controls, I agree with most on this thread, more than one sub does over power a room, this single sub can over power most rooms!, the controls allow to tailor for the room it is installed in, Good luck fellow members.

I thought my statement re: distortion was clear enough, but here's a link that should be crystal clear:

The REL R-305

If you scroll down to the THD graph, you'll see that this sub produces +/- 30% THD at +/- 30hz at 90db (quasi anechoic). BTW, this is hardly crushing SPL and as you turn it up, the story gets worse. The direction of these curves says a lot about what happens to THD as excursion increases, which was the real point of my OP.

Hope that this clarifies precisely the frequency/output levels at which a familiar sub reaches 30% + distortion.
The mention of guitar was merely made to point out that my comments were subjective as well as empirical. I'm a musician (tho sadly not a terribly skilled one) and my subjective evaluations are based on many hours a day around live music (my own) - for whatever that's worth.

And, while I play more acoustic than electric guitar, if the distortion in your class A tube amp is anything like mine, it is to be treasured - talent in a box. Not quite applicable to the conversation at hand IMO.
I am always dismayed by the clearly humorless, but that's my cross to you really think I was serious about my guitar amp? Your points have been deducted for condescending douchebaggery. any case, I don't own a 305, and seriously doubt the veracity of the test you posted if only due to personal experience...I think this guy needs better microphones.