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B&W DB1D vs REL Subwoofer


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On 28/08/2018 at 10:21 PM, Sator said:

Have I been far too hasty in discounting that brand as being more of an AV special effects' device rather than a serious audio subwoofer?

HT subwoofers might prioritise getting down to lower frequencies, or getting up to higher SPL .... and a really cr ap subwoofer might make serious compromises to do so.

 

.... however what constitutes a "high performance" subwoofer is the same no matter what content you play through it...  so I think that when we are talking about "no rubbish" subwoofers, that the idea of a "music sub" vs a "HT sub" is a total misnomer.

 

On 28/08/2018 at 10:21 PM, Sator said:

JL Audio F113 V2 

A quick look, seems like a fine subwoofer no matter if was reproducing tanks, drums, or farts  (the subwoofer doesn't know, it just needs to move with low distortion)

 

On 31/08/2018 at 12:50 PM, Sator said:

The B&W amp has to control a driver surface area that is 1.5 x (50%) larger than the JL Audio amp, despite having 1/3rd less power.

It does not take "more power to control a larger cone"

 

However (all else being equal), a smaller cone will need to move further to make the same SPL as a larger cone ..... so the small cone will require more power to make the same SPL

 

 

On 31/08/2018 at 12:50 PM, Sator said:

This modelling predicts that the JL Audio amp will achieve superior control

No.   Drop this idea.  It is incorrect.   Power does not tell you anything about "control".

 

On 31/08/2018 at 12:50 PM, Sator said:

an extra 17kg of inertia over the B&W, looking at it from the perspective of fundamental physics, it predicts that the JL Audio will sound better.

The cabinet needs to be "strong and massive" enough to prevent it making it's own sound.    You can't be sure that the weight tells you how much "self noise" the cabinet will make.

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5 hours ago, almikel said:

controlling the driver is about damping factor/low output impedance of the amp

Let's not reinforce this misnomer to people.

 

Changing the "damping factor", changes the frequency response of the driver.  That is all.

 

The idea that damping factor provides "control" to the cone (ie. that it helps the cone move more accurately) is simply wrong.

 

People are taught that without a low output impedance, that the "cone will just flap around all over because the amplifier is not controlling it" .... but this is a twisted view cooked up by the marketing department of amplifier manufacturers.

 

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18 minutes ago, Sator said:

The guy made some other extravagant claims too. He alleged that REL subs only have a phase lag of "2-3 milliseconds" and then pointed to the JL Audio claiming that it, and models from other firms, have a "10 ms phase lag"

I'd expect that it depends on whether the low pass filter is engaged.

 

If JL audio have such a bass lag, and don't offer some way to correct that (or explain that you're supposed to correct it yourself), then their product is "faulty".    So it's either JL, or the sales guy, who are doing something "wrong"  ;) 

 

18 minutes ago, Sator said:

It was also alleged that only REL's way of connecting from pre-amp to sub going through the speaker outs ("High-Level input" in REL-speak) could possibly give musically satisfactory integration between the subwoofer and main speakers.

The idea is that you "get the character of your main amplifier" coming through on the subwoofer.

18 minutes ago, Sator said:

All the other companies who connect pre-amp to sub through the RCA/LFE or balanced/XLR line outs, it was claimed, were using a deeply flawed method of connecting subs that rendered them all utterly useless

This is a big stretch.   If that's what he claimed, then that's not very good.

 

18 minutes ago, Sator said:

for serious audio systems and were only acceptable for home theatre!

Why would it be any less/more acceptable for HT?  ;)    There is music in my movies, and gunfire in my music .... how does the subwoofer know the difference ;)

 

18 minutes ago, Sator said:

Next, on discussing the REL 212 SEs, he claimed that the addition of the two passive drivers made the model superior to a sealed sub like the JL f113 for audio purposes and that in no way did passive drivers make this model more suitable for home theatre.

I have no idea how the guy would justify that claim.   This is typically the reverse of advice that is normally given.    Ported subwoofers (or subwoofers with passive drivers, which are essentially just strange ported subwoofers) are typically touted as better for HT... and sealed better for music.

 

You can probably tell though, that I'm going say that even this advice is rubbish.   A good sub is a good sub (music, HT, whatever).

 

 

18 minutes ago, Sator said:

He scoffed and talked over me repeating "NO! NO! NO—WAY!" when I pointed out these functioned similarly to ports/vents.

Oh dear.

18 minutes ago, Sator said:

The only justification he could give for these claims was that he said so and that he must be right because he was shouting louder than me. He did take smug pleasure in correcting my error in thinking that the REL S/5 SHO was a sealed model since it has a rear and down-firing passive driver, but he shot himself in the foot in stating this because this is clearly one of the reasons this REL would predictably sound inferior in a two-channel audio setup compared to the sealed f113.

LOL.     As you seem to realise.   A "passive driver" makes a subwoofer the same as a ported subwoofer.

18 minutes ago, Sator said:

Both places sound like they'd been evangelised by the REL sales reps.

They probably have.   How would they know if the REL reps were feeding them poor information?  ;);) 

18 minutes ago, Sator said:

saying that using equalisation, or even frequency response plots, was utterly pointless.

Oh dear.   (Sure, there can be problems, but)

18 minutes ago, Sator said:

pushing me towards the REL

They're not bad subwoofers....   You're just not getting very good help  ;) 

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^ It looks like the divide between ported vs sealed is indeed much blurred these days. This seems a good article:

 

https://www.audioholics.com/loudspeaker-design/sealed-vs-ported-subwoofers

 

"Unfortunately, there are a lot of popular misconceptions out there: you might hear some folks say that ported subwoofers are no good for music, and are only useful for delivering big sound effects, or conversely that sealed subwoofers are “musical”, but lack the depth to deliver the bass called for in today’s blockbusters. While some subwoofers may certainly fit these stereotypes, the truth is considerably more complex. Ultimately, sound quality is far more a function of good engineering and choosing the right tool for the job rather than a question of sealed vs ported. Nonetheless, each alignment does come with specific strengths and weaknesses, the balance of which may make one type more suitable to your situation than the other."

 

Note these statements:

 

"While not all sealed subwoofers are created equal, properly done the alignment has a lot to offer. Size is typically manageable. ... While small size tends to come at the expense of extension, sealed subwoofers generally have a shallow low-end roll-off profile, which corresponds with good performance in the time domain (i.e. group delay/ringing)." 

 

"...[P]orted subwoofers add a bit of complication to the mixture. On the upside, porting augments system output at the vent’s resonant frequency, which extends the subwoofer’s response and allows for substantially more output capability at the tuning point relative to a comparable sealed subwoofer."

 

"It should also be noted that ported enclosures are typically much larger than their sealed counterparts."

 

Again, little wonder then, when comparing the JL Audio f113 V1 against a less expensive—and much lighter—ported REL design of the SAME SIZE, the REL came off second best when tested in a two-channel audio setup. The more you look at it, the more you see how much anyone who is knowledgeable about subs should have been able to pick beforehand that the REL was always going to get left standing in this contest based on "performance/litre ratio".

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4 hours ago, frankn said:

Peak power isn’t a good metric to quote. It can be very misleading as manufacturers  use different measurements for peak or maximium power.

 

Not sure if your comment is directed at me, frankn - but the Hypex DS8.0 plate amps I am using are 800wrms (into 4 ohms).  Not "peak/maximum" power!

 

Andy

 

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3 hours ago, Sator said:

^ It looks like the divide between ported vs sealed is indeed much blurred these days.

Ported subwoofers have some basic characteristics that sealed ones don't, and vice versa .....  but that's not enough to be able to generalise which one will perform "better".

 

It would be like asking the question "which would be faster, a petrol car or a diesel car".    Clearly you could say "well, generally this, or that" ... but there is obviously no "always" answer to that question.

 

3 hours ago, Sator said:

This seems a good article:

Audioholics is generally good (especially compared to the competition) ;) 

 

3 hours ago, Sator said:

"Unfortunately, there are a lot of popular misconceptions out there: you might hear some folks say that ported subwoofers are no good for music, and are only useful for delivering big sound effects, or conversely that sealed subwoofers are “musical”, but lack the depth to deliver the bass called for in today’s blockbusters. While some subwoofers may certainly fit these stereotypes, the truth is considerably more complex. Ultimately, sound quality is far more a function of good engineering and choosing the right tool for the job rather than a question of sealed vs ported. Nonetheless, each alignment does come with specific strengths and weaknesses, the balance of which may make one type more suitable to your situation than the other."

Hah.... I should have read this first, then I wouldn't have needed to write what I wrote.  

 

3 hours ago, Sator said:

REL was always going to get left standing in this contest based on "performance/litre ratio".

Performance/litre can be very important to people....  but aside from "does it fit in my space", I wouldn't look at it any more closely.

 

Very generally, to make a higher performance subwoofer you make it bigger (bigger box, bigger cone).    Smaller subwoofers have lower performance, all else being equal .... because to get the same output, the driver needs to move more, which needs more power - and both of those things (movement and power) lead to distortion

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I’ve run a few different subs over the years including but not limited to Shiva/Redgum DIY, twin Rythmiks sealed, twin Legends with two 10” drivers each cabinet, one F113 v1 and now a pair of F113’s.

I’ve had trouble combining any of the subs with ported speakers but never really had an issue with sealed speakers and sealed subs.

One F113 was better than any of the other subs, even when I was running two. Two F113’s isn’t twice as loud as one but it evens out the performance and evens out some room anomalies.

I can’t comment on Rel or B&W but I’m more than satisfied enough to have stopped thinking about subs.

The only time I notice the subs is when I forget to turn them on. I use a low 45 hz crossover at a 24 dB slope.

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@Sator I run a couple of velodyne Digital drive 15" babies....

 

these are sealed pack a punch with some serious class D power amps built in driving them. they are VERY competent for 2ch audio and AV. I am talking clean, controlled, commanding, They dig DEEP and for 2ch I can tell you I have mains that do plenty down to 20hz and yet 40hz and below one of these makes my mains full range for a pretty smooth response 200hz-15hz back at the main listening position. This adds a kind of AIR you dont get without a sub. they also add authority, detail and means you down have to crank the system up to enjoy. av wise they both combine to something incredible. for AV a good decent sub adds really quite something taking you well well beyond anything could ever experience in even the very best commercial theatres in the country ! 

 

mine are 12 years old. so not the latest and greatest or anything but they sound as good as day one... so buy once buy well... these things can keep you very happy for many many years to come.... :)

 

ps what ever do ... do consider not only setup but measurement, EQ and integration not only with your mains but room as well. I have put a lot of effort over the years to dial in the best I can. For 2ch I am lucky the one I use is about mid central for room and find need little to no EQ but still needs integration which I do via the subs built in SMS system for it to be seamless. for AV I have both integrated via audyssey pro using a calibrated mic(can see below) so they work in well. what ever sub you get make sure you are covered off for measurement, EQ and integration ... keeping in mind before that what is most important is portion position position... of both sub and main listening position (for which the rule of 3rd comes in really handy)

26041034251_1babc3998b_b.jpg

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2 hours ago, andyr said:

 

Not sure if your comment is directed at me, frankn - but the Hypex DS8.0 plate amps I am using are 800wrms (into 4 ohms).  Not "peak/maximum" power!

 

Andy

 

@andyr - nup,  and if it was I’d say so. I know the difference between RMS, peak etc. as do you. 

 

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5 hours ago, davewantsmoore said:

Changing the "damping factor", changes the frequency response of the driver.  That is all.

 

The idea that damping factor provides "control" to the cone (ie. that it helps the cone move more accurately) is simply wrong.

 

 

You can’t repeat this enough times Dave. Damping factor affects the frequency response of an amplifier/speaker combination. And frequency response (within limits) can be equalised.

 

(Qtc is able to be equalised also... cue the red rag to the bull...).

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22 minutes ago, Sub Sonic said:

You can’t repeat this enough times Dave

Sometimes I get nervous doing it ....  the audience is important.

 

Misunderstandings about "how things work" are harmless for many/most people - who neither care, nor really need to know.     It's when it comes to people who are actually trying to understand or apply the knowledge, where it becomes a real problem.    The internet is terrible for that, where everything people say is archived forever .... for someone to land on later with the right search term.   The net (in text) is also a terrible format for laying out a stepwise example of how something works .... it's much easier in person, with a pen and paper, cos you can step through everything, at whatever pace is needed, with whatever questions are needed to clarify bits, or to confirm understanding.

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21 minutes ago, davewantsmoore said:

Sure.  Qtc is just another name for "the shape of the frequency response".     ?

Agreed. Unfortunately this is often misunderstood.

 

The penny dropped for me when I had a chat about it in person with a well regarded Australian speaker designer a couple of years back.

 

Regards,

 

SS

Edited by Sub Sonic
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11 hours ago, frankn said:

 Peak power isn’t a good metric to quote.

 

 

But increasingly this is the only parameter that the makers state as it makes the values look more impressive. JL Audio even talk about "RMS peak [sic] output" rather than RMS continuous output. Don't shoot me (the messenger), shoot the manufacturers. No, there are no independent measurements of continuous RMS output available—if there were, I would have quoted them.

 

We are in sore need of independent measurements of subwoofer performance. Not even Stereophile publish these, unfortunately. 

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Any stated power figure can be misleading with regard to output of subwoofers. SPL out depends on a number of factors.

 

Driver & box alignment/sensitivity/EQ/Xmax/thermal power handling/frequency range required of the subwoofer are factors in determining the power required. A well designed subwoofer with a 300 watt amp may well outperform a less than optimally designed subwoofer with a 600 watt amp.

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7 hours ago, Sator said:

if there were, I would have quoted them.

The point is that quoting any type of power spec does not tell you anything much useful about the performance of the subwoofer.  You should completely stop looking at it.....  because you don't so much care about how much power the subwoofer takes ... but what peak SPL it can make (over what frequency range, and below what peak distortion) ... and then decide if that peak SPL is enough for you (speaker performance will fall off a cliff as you reach the peak SPL).

 

A minivan sized subwoofer might need 20w, where an eski sized subwoofer might need 2000w to make the same SPL.  The larger power does not make it better (probably the reverse is true).

 

7 hours ago, Sator said:

We are in sore need of independent measurements of subwoofer performance. Not even Stereophile publish these, unfortunately. 

... and it's telling that when they do, they don't show anything meaningful.   https://www.stereophile.com/content/svs-sb16-ultra-powered-subwoofer-measurements

 

In short, I believe that large manufacturers do not want their subwoofers performance to be published --- as it would mean needing to explain large distortion numbers to consumers.    It's also difficult to do subwoofer measurements... and it's also difficult to compare subwoofer measurements made under different conditions....   It would shift the "trust" the consumers needs to place, from the manufacturer to the reviewer.

 

The danger may (for example) be that the consumer will not understand the difference between a subwoofer which has 20% distortion and an amplifier which has 0.1% distortion ..... and draw conclusions that the manufacturers don't like.  Controlling the narrative is everything.   In some ways, it's understandable, as data like this is very easy to misinterpret.

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1 hour ago, davewantsmoore said:

 

... and it's telling that when they do, they don't show anything meaningful.   https://www.stereophile.com/content/svs-sb16-ultra-powered-subwoofer-measurements

 

In short, I believe that large manufacturers do not want their subwoofers performance to be published --- as it would mean needing to explain large distortion numbers to consumers.    It's also difficult to do subwoofer measurements... and it's also difficult to compare subwoofer measurements made under different conditions....   It would shift the "trust" the consumers needs to place, from the manufacturer to the reviewer.

 

The danger may (for example) be that the consumer will not understand the difference between a subwoofer which has 20% distortion and an amplifier which has 0.1% distortion ..... and draw conclusions that the manufacturers don't like.  Controlling the narrative is everything.   In some ways, it's understandable, as data like this is very easy to misinterpret.

1

 

Yes, Stereophile does publish those "measurements" of in-room frequency response plots, which aren't anything more than what each of us could take in our living rooms. I don't think that counts for much so have chosen to discount them. It seems active speakers, in general, are a bit tricky to measure, and John Atkinson doesn't/can't really test the amplifier separately (at least not without disassembling the sample unit submitted by the manufacturer)  e.g. https://www.stereophile.com/content/dynaudio-focus-200-xd-powered-loudspeaker-measurements

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16 minutes ago, Darren69 said:

I always thought subs needed massive power until I took delivery of my pair of REL S3’s. 400w each and never stressed in my setup even when I am drunk 

 

These are class AB amps, IIRC. Even at 400W, if you measured the average power consumption, they may well consume more than a Class D "1000W" amplifier, these being more power efficient as a class.

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1 minute ago, Sator said:

 

These are class AB amps, IIRC. Even at 400W, if you measured the average power consumption, they may well consume more than a Class D "1000W" amplifier, these being more power efficient as a class.

Power of an amplifier is normally stated as it’s output, not it’s input. Efficiency therefore should not enter into it.

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17 minutes ago, Sator said:

 

These are class AB amps, IIRC. Even at 400W, if you measured the average power consumption, they may well consume more than a Class D "1000W" amplifier, these being more power efficient as a class.

Power ratings aside, I bloody love them and doubt I would own a sub that wasn’t made by REL these days. So regarding your op, REL all the way!

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25 minutes ago, Sub Sonic said:

Power of an amplifier is normally stated as it’s output, not it’s input. Efficiency therefore should not enter into it.

Supposedly so, but when people have measured the Devialet 200 (200W into 6 Ohms) Class D amp's average power consumption they found it was around 26-29W at typical listening volumes. 

 

https://devialetchat.com/thread-255.html

 

For the Devialet 250 (dual mono 250W into 6 Ohms) Class D amp the figure is around 31W:

 

https://devialetchat.com/thread-1413.html

 

So manufacturers massage their figures in different ways and this appears to be especially true of Class D amps.

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It seems active speakers, in general, are a bit tricky to measure

No, there’s nothing about an ‘active’ speaker which makes it any different to measure.

However, ALL speakers are tricky to measure and present in a way which is meaningful, and not open to misinterpretation.
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