Honesty in specifications

[kemmler3D]

But if you consider things like a trombone is often quoted as 110dB and a traditional pipe organ with 16 Hz pipes is powered by the organist's feet, it seems like it should be possible to produce a high fidelity music system that can accurately reproduce such natural instruments without a 10,000 WRMS amplifier and 36 inch drivers.

Musical instruments are based on resonance and convert mechanical energy directly into sound, with (I guess) very high efficiency. Loudspeakers generally try to avoid resonance altogether, or at least use it sparingly, and need to convert electricity into a magnetic field, which is then in turn converted into motion and sound. So the human power input is maybe a watt or two for instruments, but speakers have to produce the same sound with no efficiency advantages to speak of, compared to instruments.

I just wish they would make something more along the lines of the KEF KF92 which is clearly oriented more toward high fidelity music than shaking the neighbor's paintings off the walls while watching End of Tomorrow.

The distinction between properly designed "home theater" and "music" subwoofers is mostly imaginary. Subs are much simpler than normal loudspeakers because diffraction and dispersion are basically a non-issue. All you really need to look for are the frequency response, CSD, distortion and max SPL / compression plots and you've got the whole story.

IMO "home theater" subs have a reputation derived from nasty 90s-2000s HTIB stuff that was mostly an 80hz resonator with no power to speak of outside that. So you end up with the stereotype that "home theater" subs are for movies and just make booming noises, and "music" subs are different in some way. But the truth is, there's no real distinction as long as you've got something decent on your hands.

I would check out @sweetchaos 's subwoofer comparison chart rather than chasing manufacturer measurements. https://www.audiosciencereview.com/forum/index.php?threads/subwoofer-comparison.20494/ - there's a lot to go on. I also think Erin's Audio Corner has measured a fair number of subs.

From those, there ought to be a few viable options.

As for the "Harvard MBA" factor... really no degree is necessary. Just interact with a few of your customers, observe that your competitors are lying, and realize that shooting yourself in the foot is counterproductive. I used to work for a speaker company, and even though our speaker outperformend nearly everything in our price range, publishing detailed measurements would have done us about as much good with mainstream consumers as publishing circuit diagrams labeled in ancient greek.

Even our most ardent supporters sometimes bought into snake oil and didn't really understand measurements. It's just a less common skillset than you'd think reading a site like ASR.

 

[sigbergaudio]

Yes, the Harvard MBA ideology is a major obstacle as you state.

But if you consider things like a trombone is often quoted as 110dB and a traditional pipe organ with 16 Hz pipes is powered by the organist's feet, it seems like it should be possible to produce a high fidelity music system that can accurately reproduce such natural instruments without a 10,000 WRMS amplifier and 36 inch drivers.

Well, a 16hz organ pipe is 32 feet long, so the real instruments do take a bit of space too. And a trombone at 110dB is probably not the lowest frequencies.

I just wish they would make something more along the lines of the KEF KF92 which is clearly oriented more toward high fidelity music than shaking the neighbor's paintings off the walls while watching End of Tomorrow.

As I mentioned, we do.

 

[JimA84]

Musical instruments are based on resonance and convert mechanical energy directly into sound, with (I guess) very high efficiency. Loudspeakers generally try to avoid resonance altogether, or at least use it sparingly, and need to convert electricity into a magnetic field, which is then in turn converted into motion and sound. So the human power input is maybe a watt or two for instruments, but speakers have to produce the same sound with no efficiency advantages to speak of, compared to instruments.

The distinction between properly designed "home theater" and "music" subwoofers is mostly imaginary. Subs are much simpler than normal loudspeakers because diffraction and dispersion are basically a non-issue. All you really need to look for are the frequency response, CSD, distortion and max SPL / compression plots and you've got the whole story.

IMO "home theater" subs have a reputation derived from nasty 90s-2000s HTIB stuff that was mostly an 80hz resonator with no power to speak of outside that. So you end up with the stereotype that "home theater" subs are for movies and just make booming noises, and "music" subs are different in some way. But the truth is, there's no real distinction as long as you've got something decent on your hands.

I would check out @sweetchaos 's subwoofer comparison chart rather than chasing manufacturer measurements. https://www.audiosciencereview.com/forum/index.php?threads/subwoofer-comparison.20494/ - there's a lot to go on. I also think Erin's Audio Corner has measured a fair number of subs.

From those, there ought to be a few viable options.

As for the "Harvard MBA" factor... really no degree is necessary. Just interact with a few of your customers, observe that your competitors are lying, and realize that shooting yourself in the foot is counterproductive. I used to work for a speaker company, and even though our speaker outperformend nearly everything in our price range, publishing detailed measurements would have done us about as much good with mainstream consumers as publishing circuit diagrams labeled in ancient greek.

Even our most ardent supporters sometimes bought into snake oil and didn't really understand measurements. It's just a less common skillset than you'd think reading a site like ASR.

The Harvard MBA reference is for companies like Bose that market poor quality products using misleading tactics.

As for "home theater" it's alive and well even at the best companies. Sort of car audio on crack. Check out Wilson Audio's Thor's Hammer. You'd need a forklift to install it, and you'll likely become a regular customer of the local police department.

Or just read some of the comments even here. You can buy a huge subwoofer with an amp that requires rewiring to feed that can produce over120 dB at 20 Hz and likely shake the plaster off the walls.

And some of these are reputable companies where they list the distortion specs in addition to peak SPL. Unlike the 4000W car audio stuff that barely hits 80Hz

I just want something which will accurately reproduce a 16 Hz organ note, will not self destruct when fed a movie soundtrack, and which I can move without having to call a chiropractor. And which can match but not necessarily exceed the SPL of the main speakers.

Unfortunately most "subwoofers" in this range either aren't subwoofers at all, meaning little response below 30 Hz or are hulking behemoths like Monoprice's otherwise excellent 16 inch Monolith or JL's Gotham.

Most of the others carefully avoid any reference to peak SPL at low frequency and offer no distortion figures.

And most reviews are of the "Oh, gosh" nonsense.

What is frustrating is that when someone really tests them it's typically like when Amir hooked up a four ohm load to an Onkyo TX-RZ50 and it instantly panicked.

I am not interested in causing the next earthquake. I do want something which sounds good at full reference volume.

This seems to be a sparse marketspace.

It's like being offered a tarted up IBM-PC clone or an IBM z/OS mainframe with nothing in between except marketing hype.

 

[MAB]

But for a company like ELAC to offer specs like: "Anechoic 18 Hz, In Room 14 Hz" is worthless. The Fs doesn't magically change in a room

I agree that there is too much liberty taken with speaker specifications. For instance, quoting a 3dB down point anechoic is legit. Adding some reference, like CEA-2010 is also helpful since it at least gives the transfer curve. Quoting in-room response is not OK, since each room will augment the bass response of a woofer in different ways. That Elac dual 12" sub that I think you are referring to is a nice one, and does go very low, but I am not clear it will hit 18Hz anechoic at -3dB. I would want to see some more standardized method, like CEA-2010.

By your statement above, it seems you aren't aware that room gain is real. Boundaries augment bass compared to anechoic.

And CEA2010 doesn't begin to approach reason because it's limited and easily spoofed.

Can you explain? I would agree that it isn't perfect, but "doesn't begin to approach reason" is not clear and I need it explained. Please elaborate on "easily spoofed". Do you have a proposal?

I have a subwoofer that I am interested in to reproduce 16 Hz pipe organ but I can't get a straight answer from anyone.

Do you mean you are looking for a subwoofer that can realistically reproduce a pipe organ? Or that you already have one, sorry the sentence isn't clear. If you are sub shopping, what model are you looking at? 16Hz is a hard task. If you want above 105dB at 16Hz then something like a JTR captivator. If 100dB a Dayton Audio 18" is about as cheap as you can get. But I say this based on CEA-2010 data, and am perplexed by your claim. And not sure what SPL you need and room size you have.

 

[Mnyb]

A 16Hz organ pipe is 32 feet and powered by an electric blower of sort the organist feet’s just modulates them .
Small home type organs are pumped by the organist . The bigger ones used to have bellows before electric blowers with people maning the bellows .

How big is a double bass how big is a kick drum or orchestral drum there’s a proper size comparison.

I jus sold my rhythmic FV15HP it was possibly capable of producing 16Hz at a decent level . But it’s misses your spec by a factor of 2 it took 2 people to move the thing and it was big due the bass reflex design .
Bass reflex subs gets big due the internal volume needs to be bigger and ports are long and big . But they are efficient and will yield the spl needed for decent 16Hz playback.

A sealed sub gets smaller and with EQ and more power you can use an even smaller box . They are limited by the area of the driver and it’s xmax ( travel back and forth ) it’s basically displacement and physics. A 10” driver would have to work really hard to produce 16Hz at a levels that give the body feel you get from a big organ where talking driver movements about and inch or more ? If your lucky with room gain and can use a corner , maybe ?

I’m replacing my whole system and would possibly use a setup with two smaller subs , you can move them one at the time by yourself

 

[raindance]

The old Hsu cylinder subs could do it and they were pretty lightweight also. They were supplied with an EQ module and provided meaningful output at 16Hz with a smallish footprint.

 

[JimA84]

I agree that there is too much liberty taken with speaker specifications. For instance, quoting a 3dB down point anechoic is legit. Adding some reference, like CEA-2010 is also helpful since it at least gives the transfer curve. Quoting in-room response is not OK, since each room will augment the bass response of a woofer in different ways. That Elac dual 12" sub that I think you are referring to is a nice one, and does go very low, but I am not clear it will hit 18Hz anechoic at -3dB. I would want to see some more standardized method, like CEA-2010.

By your statement above, it seems you aren't aware that room gain is real. Boundaries augment bass compared to anechoic.


Can you explain? I would agree that it isn't perfect, but "doesn't begin to approach reason" is not clear and I need it explained. Please elaborate on "easily spoofed". Do you have a proposal?


Do you mean you are looking for a subwoofer that can realistically reproduce a pipe organ? Or that you already have one, sorry the sentence isn't clear. If you are sub shopping, what model are you looking at? 16Hz is a hard task. If you want above 105dB at 16Hz then something like a JTR captivator. If 100dB a Dayton Audio 18" is about as cheap as you can get. But I say this based on CEA-2010 data, and am perplexed by your claim. And not sure what SPL you need and room size you have.

It turns out from graphs I have seen the ELAC has a very sharp rolloff below 20 Hz which leads me to believe the driver has a Fs around 20 Hz. Which from my perspective is unfortunate.

Keep in mind some Rockford and other car stereo oriented subs use 4,000 watts weigh over 50 Kg and still have a Fs of 80 Hz.

I am interested in dual opposed speakers with a Fs around 16 Hz and which can hit around 105 dB at 16 Hz with reasonable distortion.

This is well within contemporary technology.

The problem from my perspective is the market for this seems small, so with MBA driven corporate culture it's either a mammoth sub that needs a forklift to install or something that makes at most around 80 dB SPL below 20 Hz.

I am an engineer and scientist so I definitely understand the technology.

It's the frustration of getting honest, realistic specs and something designed to produce high fidelity bass at a reasonable volume.

It seems like everything is either way overrated or else some gigantic 400 pound monster that will take up the whole room and in some cases still fail to deliver because it's car audio tuned to 80 Hz and above.

 

[Ellebob]

I think 16hz @ 105db less than 80 pounds is a very tough find even with unlimited budget.

 

[JimA84]

I think 16hz @ 105db less than 80 pounds is a very tough find even with unlimited budget.

Only if you're a consumer, not an electrical engineer.

 

[sigbergaudio]

Only if you're a consumer, not an electrical engineer.

Are you looking for 105dB@16hz in-room or anechoically (which is what most specifications are)?

If you are talking anechoically you will struggle to find any sealed subwoofer that does that, and if you do it's probably a dual 15" or something. So it will not be less than 80 pounds, I can tell you that right now. If you are talking about in-room (so with room gain), it's another matter.

 

[MAB]

It turns out from graphs I have seen the ELAC has a very sharp rolloff below 20 Hz which leads me to believe the driver has a Fs around 20 Hz. Which from my perspective is unfortunate.

Only if you're a consumer, not an electrical engineer.

I don't think you have your understanding straight.
Two long-throw 12" drivers are going to struggle to get to 20Hz anechoic. Even with room-gain. If you have an example, can you show?

The rolloff is likely the DSP limiting the response below 20Hz. For instance, here is about the most robust 18" driver I can think of in a sealed box.

Very few 18" drivers will outperform this one. It just makes it to 105dB at 16Hz, at 2000 Watts. You can EQ it flat, but you are limited if you intend to hit 16Hz flat. Of course you would need a steep filter below to avoid over-excursion, and you would be running at the outer limits of the driver and your breaker box.

Dual 12" aren't going to have as much useable output as this 18" driver. For instance, two Scan Speak drivers in a sealed cabinet:

600W is above the limit for this driver, I assume it is thermal but don't know for sure.

Both of these subs would be large and well over 100 pounds.

I agree specs are not always useful, but you have some slightly unrealistic expectations.

 

[sigbergaudio]

Here is [email protected] and 8.4% THD @1m in a 20m^2 room (so helped by room gain). One subwoofer corner placed. The subwoofer weighs 59 pounds (29kg).

 

[JimA84]

Are you looking for 105dB@16hz in-room or anechoically (which is what most specifications are)?

If you are talking anechoically you will struggle to find any sealed subwoofer that does that, and if you do it's probably a dual 15" or something. So it will not be less than 80 pounds, I can tell you that right now. If you are talking about in-room (so with room gain), it's another matter.

Room gain is very dependent on the particular frequency and the room geometry, construction materials, etc.

What room gain CANNOT do is magically lower the Fs of the transducer.

TNSTAAFL.

In other words the room gain might reduce the transmission loss at short distance, but it can't add something that isn't there.

If the transducer falls off dramatically below 20 Hz as the ELAC appears to do, claiming in room response Hz below the anechoic response is an illusion.

You can't add back what isn't there to begin with.

You have to understand that "room gain" only means lower loss with distance.

"Room gain" CANNOT add anything.

 

[JimA84]

Room gain is very dependent on the particular frequency and the room geometry, construction materials, etc.

What room gain CANNOT do is magically lower the Fs of the transducer.

TNSTAAFL.

In other words the room gain might reduce the transmission loss at short distance, but it can't add something that isn't there.

If the transducer falls off dramatically below 20 Hz as the ELAC appears to do, claiming in room response Hz below the anechoic response is an illusion.

You can't add back what isn't there to begin with.

You have to understand that "room gain" only means lower loss with distance.

"Room gain" CANNOT add anything.

Perhaps to elaborate, you can't add energy to anything with a passive device.

A horn instrument doesn't "amplify" the sound from the mouthpiece, it just couples it more effectively to the surrounding air.

Much as Klipsch has made some very efficient speakers by using horn technology to couple the transducer output to the room. They sound louder for the input power simply because they are more efficient.

This doesn't add any "gain," it simply makes more of what was already there.

In particular, you can't magically lower the Fs of a bass transducer by the enclosure.

Hence my annoyance at ELAC claiming a much lower frequency response due to "room gain."

I have seen frequency response graphs that indicate that the Fs of their drivers is somewhere around 20 Hz. The response falls off very dramatically below 20 Hz.

So it's pretty hard to buy their claim of 14 Hz "in room" extension.

Some competitors have clear response down below 16 Hz, but at very modest SPL, meaning it will be inaudible with main speakers of good efficiency and high output.

It mainly comes down to misleading marketing.

It's kind of the opposite of 1960s "musclecar" makers who quoted absurdly low HP numbers to placate insurance companies and government agencies.

OTOH you can find Rockford car stereo subs with nearly 200 pound magnets and 4,000 watt power ratings that have zero response below 80 Hz.

And you can't alter that 80 Hz with "room gain."

 

[Mnyb]

In a selaed box it’s the combined fs of box and driver that counts below that the output falls naturally at 12dB per octave ( it’s higher than the drivers own fs in free air ) , I don’t know the exact math for an ideal q of 0,5 then you get a box without an exaggerated “hump” higher up ok ?

That means that if for example the combined system has a natural fs at 30Hz it’s only 12dB down at 15Hz so it’s not impossible to get that back by so called room gain ,which in reality is the rooms resonance modes that augments the combined system output at some frequencies depending on it s dimensions .
With such low frequencies there is no separating the speaker from the room they are one system .

The fishy part of such marketing claims are not the room “gain” effect . But rather who’s room and at what level ?
Resonance peaks exceeding 10dB or more ( 20dB ) in room are not unusual, but where they are is depending on room dimensions and construction. Yes so showed into a corner or close to a wall my theoretical 30Hz sub could be be back at full level depending on the room ?

This also means that the frequency response is a mess and that why we need EQ

In practice there are complications, mostly human complications almost no one wants to live with the box size physics gives for a given combination of driver and box .
Also if you stuff two drivers in the same box the internal volume should also be doubled .

What a practical subwoofer manufacturer do is to use a way to small box for the drivers and use extensive EQ that’s why you see absurdly powerful amps in subwoofers ( like the 1000w in a kef kf92 ) then you can utilise the drivers xmax anyway, it places demands on the drivers to tolerate power . This is one factor leads for the need for limiters in subs .
They are balancing two factors the drivers travel in and out ( stroke , xmax , xmech ) and how much power it can tolerate.

Vented subwoofers or bass reflex as it’s called works in a different way, the pipe on a bass reflex speakers is a Helmholtz resonator ( blow on an empty bottle for a demo ). This is tuned to below the fs of the driver so the combined response now goes lower than the drivers natural fs in free air and the resonator augmenteds the efficiency of the system ( theoretically the driver does not move at all at the port tuning frequency ). So you get more bass and lower frequencies for a given driver .

Caveats , with a vented box the response is now falling at 24dB per octave and it should not be used far below the port tuning frequency and it a bigger box than sealed, much bigger . This gives a need for yet another limiter in the sub.
This also gives that you want a big vented sub if you need low frequencies you need the port tuning to be really low.
There are more complications, but we leave that for now .
Btw the FV15HP I had could vary the tuning with inserts to be 20Hz or 14Hz or sealed .

The handling problem of an awkward and big box can solved by using more than one sealed sub the combined output may suffice , stack them in a corner.

Form factor . Sigberg one of the users that comments in this tread actually makes subwoofers he is a manufacturer and thus by forum rules can’t promote his own stuff to much . He has 2 types of “flat pack” subwoofers that goes for example on the wall or under a sofa or under a table .

Also CEA2010 can be hard to read if you don’t observe the subtleties it’s a pass/fail for each test tone in the set at a certain distortion level so if sub measurement to this standard does not provide data below 20Hz does not mean that the sub does not work below that , it just won’t do it according to this standard.

 

[Mnyb]

More complications, with the limiters built into to modern subs and the natural physics of it .

Measurement with CEA2010 may also give the impression that a sub is very non linear.

But it’s simply that it’s much more capable at 100hz so it does not hit a limit . It no longer needs to fight the too small box with extra power, and cone travel is less for a given output

 

[Mnyb]

So the real limit is not fs frequency but in reality the displacment of the driver surface area times the stroke . the rest can be EQ'ed .
To make this happen with a small driver the travel of the cone will be unrealistically large ?

As mab pointed out two 18" in closed box struggle to do it even theoretically .

 

[sigbergaudio]

@JimA84 With all due respect, you don't seem to know exactly how this works. I've seen subwoofers that have drivers that has ~20hz fs go flat to 10hz in-room. A sealed subwoofer without an active high pass filter will roll off with 12db/octave, and at frequencies as low as we are talking here, you can easily get that back with room gain (depending on the room of course). The dramatic drop in the elac is probably due to an active high pass filter, but even despite that I suspect their claims might be true.


As another example, I'm currently designing a ported loudspeaker with a port tuning of 28hz. It has a -6dB point of 18hz at the listening position in my living room, despite a ported speaker actually rolling off at 24db/octave below the port tuning. I think you are underestimating the effect of room gain at low frequencies. You also seem to not understand exactly what the fs frequency means. This is the point where the driver requires the least power, but it is not a limit for how low it can go. Case in point, the fs itypically becomes higher when put in a small, sealed box, but this doesn't prevent the driver from playing low frequencies. We use drivers with a fs of 21hz, and they play 10hz and below just fine.

You are making this hunt unecessarily difficult for yourself. I've also hinted more than once that we actually build exactly the sub you seem to be looking for, did you even look at them? It seems to me you are more interested in bashing manufacturers than actually finding a sub.

 

[OldHvyMec]

And I have no reason to trust or believe any of them.

Make your own sub with an amp and a raw driver, that’s how you know a sub will do what you want.

That was easy. Personally I like big speakers, BUT 16hz?

It's one thing for a driver, then a cabinet/plate combo to be able to hit 16hz with any authority but the ROOM and setting it up to
accommodate 16hz will be the greater challenge. There are certain metrics mechanically, that have to be in place first or you'll
be adding them later. DSP isn't going to be doing that no matter what anyone claims. It's a shaping tool, but you still have
to have something to shape and 16-25hz is not a plaything. In real life 110db at 16-25 hz you better have your mouth open
for any sustained period. It has bone demolition abilities with just a few more DB.

Your neighbors will probably want to kill you, no question about it. Decoupled in a perfect room, everyone in that domicile or
close proximity will still FEEL it at any SPL.

Fruit for thought with a 19hz all day long system. It took a while to get that 19-20hz FR with a planed room! Off the wall room
shapes and open concepts are never going to get there. Some of the rooms I've seen, just buy headphones and set on a sub!

Regards

 

[Mnyb]

This article by SVS another sub brand . This is marketing but describes the phenomena fairly correct .
The marketing part is that it is is a well chosen example where the room gain magically meets the natural roll off their products and a lot of smoothing of the curves presented

https://www.svsound.com/blogs/subwoofer-setup-and-tuning/what-is-subwoofer-room-gain .

Thier SB-2000 product looks nice for example.

Sigbergs curves in a post above us looks messier but are more real .

In reality for good integration you need to measure the sub in your own room and try different placements . and correct with EQ .
The long wavelength off bass compared to room size is why it all behaves as one unit , so you cant really listen to subwoofers the room always modulate the output .

So typical in room output what is that whos room ? Sigberg presnts data from his own room as an example . but the room gain phenomen is real and has to be taken into account both when designing subs and integrate them .
So some of them like to take a guess and presents a single number that looks both good and somewhat credible , but it should be presented with massive error bars .

It's up to you to integrate this in you room .

I would look for products that have some way off making this easier and also are of high quality . PEQ ia a good feature in a sub if you don't have it elsewhere in the chain