Why the fuss with subwoofer specs and brands?

[sarumbear]

What has that got to do with the price of cheese?

The only point I am trying to make is that I do not see any reason to ascribe any special requirements to movies with regard subwoofer capability compared to music in a domestic setting.

I wish you knew the difference.

Anyway, Happy New Year.

 

[jsilvela]

This thread has had some very informative posts by insiders that managed not to get sternly precise.
And not to declare the price of entry into the arena a 5.1 system, or movies distributed globally after 1990.
This detour into movie upmanship is getting long and taking us off track.

The point, I think and hoped when I started this thread, was about reframing the "must do's" for subs and LF.
Not "you need a sub for movies, otherwise your system is worthless", but "you'll miss such and such in this kind of movie".
Not "haha you have an 8 inch REL", but "here's how to know if you're getting what you need".

I can be pedantic in my specialty if I want, but it serves little purpose when talking to non specialists.

Any way, logging of for the remaining 4 hours of 2022 in Madrid. Wishing you all good things in 2023.

 

[rcstevensonaz]

Hence we are discussing LFE channel, which is part of surround film sound track.

But for a few of us, we have been discussing the input on a subwoofer labeled "LFE".

Including the recent digression where @sarumbear is providing some very helpful insight from the perspective of the *source media*, this thread has cleared up a significant confusion that I have had about when to use a subwoofers "LFE" vs "Main R & L" inputs. Originally, I had assumed that the subwoofer's LFE input should ONLY be feed the LFE output from the source.

What I have learned -- from the view of the subwoofer connection called "LFE":

• If the AVR (or 2.1 stereo amp) is not doing any bass management, then the AVR's subwoofer out will only send the LFE channel from the source media. In this case, in addition to the subwoofer interconnect, you need to also need to connect the Right & Left channels (either speaker-level or mains-level) to the subwoofer if you want it to also provide low-end bass for the speaker channels in the source media.

• If the AVR (or 2.1 stereo amp) is doing bass management, then the AVR's subwoofer out will include both the LFE channel from the media source as well as the low-bass from the speaker channels in the source media. In this case, you only need to connect the AVR's subwoofer out to the the "LFE" connection on the subwoofer. Which means the "LFE" jack on the subwoofer is incorrectly (and confusingly) named because it is actually receiving both the LFE channel and the lower-bass range for the speaker channels ("right & left") in the media source.

What I also learned is that it is always important to be clear which part of the audio chain your answer relates to. The term "LFE" actually means very different things if you are talking about the LFE channel in the media source or the LFE input jack on the subwoofer.

 

[bluefuzz]

Possibly because you are using a stereo down-mix (a legacy track meant for TV) and not have access to the LFE channel.

How difficult is it to understand that the vast majority of the movies I own have little to no low frequency content? The majority of them being probably recorded on a clapped out Nagra III in glorious mono. And again, this is all essentially irrelevant to this thread. Please stop your tiresome grandstanding.

 

[sarumbear]

How difficult is it to understand that the vast majority of the movies I own have little to no low frequency content? The majority of them being probably recorded on a clapped out Nagra III in glorious mono. And again, this is all essentially irrelevant to this thread. Please stop your tiresome grandstanding.

Happy New Year. Enjoy your retirement.

 

[Willem]

As an owner of dual REL T/5i subs, do you mind if I play this game as well?

1. Small size. We were in a 834 sq ft, 2 BR apartment; the small living room area included our dining table, TV & audio rack, couch, and my wife's loom.
2. Finish (piano white). The subs were in our only living area; so having something that aesthetically blended in well was very important.
3. Apartment life. While loud SPL and deep low bass would be great for us, the neighbors next to us and below would strongly disagree. Thus, I was not focused on the LFE range (e.g., below 30Hz) or an ability to play loud.
4. Focal Aria 906 (6.5" mid-woofer). My focus was primarily to pick up the lower-end of the music range (and "average" movie effects in a typical movie) that are just beyond what the Focal could deliver; primarily in the 32Hz to 80Hz range.
5. Musicality. Equally critical was a sub that would easily integrate "seamlessly" in the cross-over from the 906 to the Subwoofer. An 8" woofer or 10" woofer can fit this range nicely, retaining a small footprint. A few of the sealed 12" subwoofers were potential, but they really pushed hard against the upper limits of #1 and #3 above.
6. Sealed Sub. For a lot of reasons (some right, some wrong), I have remained focused on sealed subs over ported subs.
7. Dual Subs. Because the room is so small and because we have no options for treating the room, I wanted 2 subs to allow for smoother response.
8. Affordable. Was ideally looking for subs in the $300 range, but could go up to $500 per sub.
9. High Level Input. I was not in a position to invest heavily in DSP and room correction software to calibrate the integration between subwoofers and speakers (largely due to lack of any time). So the ability to use speaker connections was very helpful.
10. [DSP Should Be Avoided]. Full disclosure: at that time, I still believe that "Pure Direct" mode on my Denon AVR was the best (and the only right) way to listen to 2-channel music. So even if I had the time to invest in room correction, I still would not have. Which meant a requirement for speaker-level inputs... which nearly all small subs offer anyway.
11. [REL "Magic Musicality"]. On this, I didn't know any better at the time. I believed their method of speaker-level input was an advantage. I believed that using an 8" woofer would be "faster" and more "musical" in the 35Hz - 80Hz range. I believed that if the primary focus was music, buy REL; and if the focus is movies, buy SVS or HSU. And I always prioritize music over movies.

The REL T/5i — on sale at $499 each (March 2020) — met all of the requirements above (especially size and finish!!!); and the "REL Magic" was viewed as an incremental benefit. Their marketing is effective; but it was not the primary selection criteria since the REL T/5i was the only possible sub from REL that I would even consider based on affordability and size. Even though their sizing calculator indicated I should have ordered REL T/7i, but it was too expensive to consider (and larger than I wanted).

Looking back, now that we I am in a larger rental house, I'd prefer to have a pair of SVS SB-1000s. They were larger than I wanted, but otherwise meet all of the requirements above (except #10 ). However, I also had a fear that their 12" subwoofer (with no DSP) would not mesh quite as seamlessly with the Focal 6.5" mid-woofers, compared against an 8"or 10" subwoofer. Given the size factor and our very small living space at that time, I think I still would have selected the REL T/5i.

Beyond SVS, I don't recall any other subwoofer options that included Piano White or another nice finish option that were (a) affordable, and (b) well regarded.

Of course, now that I am in a rental house with a larger living room (14' x 20', open hall to kitchen and stairs), I am trying to figure out if I am better off selling the pair of REL T/5i subwoofers and picking up a dual SB-1000 and an SB-2000 (for 3 total), or just keeping the two very nicely sized REL T/5is (placing them close to the Aria's) and adding an SVS SB-2000 or SVS-3000 in the back of the room to round out the nodes and help fill in the deeper bass range.

The Rel subs look good and I agree that that is important. Sonically they were expensive, but that is a done thing. Selling them makes no economic sense.
If you want to spend some money for more and better bass, getting a bigger third sub would make financial sense and produce the best possible sound with deeper and smoother bass. And use MSO.

 

[bodhi]

And for the size, they do kick hard.

Yep. In medium size room two can play 105dB in low teens. Something with it being so small still irritates subwoofer fans and even with measurements people just dismiss it.

Well there is the thing that if you can fit couple ported beasts then you get same results for half the money.

 

[Sancus]

Most people prefer flat direct sound, the slope at the listeners position depends on the directivity of the loudspeakers, room reverberation slope and listening distance, which is why above transition frequency correcting the LP response to some predefined targets usually doesn't work well. More about it here https://www.audiosciencereview.com/...ut-room-curve-targets-room-eq-and-more.10950/

I was only referring to this graph which is also in your thread. The "predicted steady state curve" is down by about 3-4dB between 100hz and 1khz. This also matches up with the PIRs in reviews, for good speakers they tend to be around 3-4dB down in this range as well. Depending on directivity. This is a "typically-reflective" room which is of course silly, most people aren't going to have an exact room match. But it also says "flat direct sound". Yet pretty much everybody, even the trained listeners, preferred more bass than that.

I'm also aware this was a small study, but that lines up with reality for me. Most room measurements I see have more tilt, somewhere between the predicted curve and the "all listeners" one. Home Theatre enthusiasts tend more towards the 5-10dB side of things, for sure, and I have seen a few at 10dB+ but that is rare.

Given the circle of confusion, recordings have arbitrary amounts of bass in them so it's not really possible to have a precisely correct amount of bass anyhow.

 

[thewas]

I'm also aware this was a small study, but that lines up with reality for me.

They can but as said this doesn't mean they must, for example listening in nearfield or with very wide radiating designs and/or reflective rooms will make the slope less and vise versa.

 

[rcstevensonaz]

So under the framework of "why the fuss with subwoofer specs and brands", two questions that I still am still not sure if I need to "fuss" about. Assuming the use of either Audyssey MultiEQ-X, miniDSP 2x4, REW, etc. for integrating multiple subs (2 to 4):

1) Does Continuous Phase Control on the subwoofer matter? If using one of the common DSP solutions and multiple subs, is there value in a subwoofer that has continuous phase control vs. the simple 0 / 180 degree flip?

2) Does Built-in DSP on the subwoofer matter? If using one of the common DSP solutions and multiple subs, is there benefit in the additional cost (and higher group delay) of having DSP built into the subwoofer as well? For example, in a video that Erin posted for "Monolith vs. SVS", his take away seems to be if you already have a good DSP mechanism, there is no need for it to be built into the subwoofer (thus Monolith is the choice for that scenario). But I believe I've read other people suggest that there is still benefit for built-in DSP since you can first tune the sub to the room using the subwoofer's built in DSP, and then use your system-wide DSP / MSO to integrate the various subs together. And, what about the consideration that a person could always upgrade to the next generation of Audyssey / miniDSP / etc., but they will always be stuck with that vendor's DSP implementation built into the sub for the next 10+ years.

Depending on the answer to those questions, there may be significant reason to fuss over the brand and specs. Or, alternatively, one could simply treat all competently built subwoofers the same (without regard to features such as continuous phase control or high-quality built-in DSP capabilities).

 

[jsilvela]

The majority of them being probably recorded on a clapped out Nagra III in glorious mono.

A brilliant movie where a glorious Nagra (not sure which model) plays a key role is the French cult classic Diva: https://www.imdb.com/title/tt0082269
If you haven't seen it already, I suspect you'd like it.
It can be enjoyed immensely, even on a :gasp: legacy system.

 

[Puddingbuks]

Happy New Year. Enjoy your retirement.

Maybe a good new years resolution for you: be nicer to people.

 

[bluefuzz]

A brilliant movie where a glorious Nagra (not sure which model) plays a key role is the French cult classic Diva: https://www.imdb.com/title/tt0082269

Yes, one of my favourite movies. The Nagra used is a IV-S I think – the stereo version.

I actually own a couple of mono Nagra IV models. Absolutely amazing build quality.

 

[jsilvela]

Yes, one of my favourite movies. The Nagra used is a IV-S I think – the stereo version.

I actually own a couple of mono Nagra IV models. Absolutely amazing build quality.

Ah, good, great movie.
Wow, I'm envious about the Nagras!!
Speaking of movies, I started getting into ASR and REW and measurements because I noticed in the soundtrack of "In the mood for love", that there was some boominess in the low cello notes. Which seems gone now I'm correcting with EQ. (Yumeji's theme is the name of the song).
That there is another movie you can love, *even* without a sub.

 

[jsilvela]

Ideally, you would have no room influence in your bass response and not need any DSP to correct it (not reality). The video I posted bases their business on trying to get their customers as close to that ideal as possible (mostly for rich people and professional music), and isn't very interested in half measures. It's an extreme goal, but that doesn't make him wrong, and understanding the extremes is very helpful and informative. Room sound is lower quality than direct sound, and even if that's less impactful in the bass region, it's still true and it's part of the reason we treat rooms. My own more realistic goals are to reduce the room sound as much as possible within my budget and aesthetics before applying DSP, even if that's nowhere near what Acoustic Fields sells. The information he provides is very useful, even if not 100% directly applicable to my space (just like most things in acoustics). Shoving a sub in the corner will absoltely give you a boost, but that boost is all room sound.

I've been doing some experiments with placement this morning.
I don't have that much freedom, but I pushed the sub away from the corner and farther into the center of the wall.
And, not that much difference, still very messy response, i guess still a lot of "room" there.

But I like your idea of getting the response as smooth as possible *before* doing EQ.
And I have found that in the corner, messing a bit with the separation and the toe-in, I managed to get a smoother curve.
After EQ via my computer (waiting a while before splurging on a DSP box) I am pretty happy with what I've managed.
Thanks for your suggestions!

 

[Dal1as]

Yep. In medium size room two can play 105dB in low teens. Something with it being so small still irritates subwoofer fans and even with measurements people just dismiss it.

Well there is the thing that if you can fit couple ported beasts then you get same results for half the money.

While impressive for a tiny woofer 2 of them can't even hit 105db max output let alone in the teens. Come on now.

KEF KF92 review

Awesome low-end from a cute, compact cube

www.whathifi.com

 

[ex audiophile]

To change the subject a bit and perhaps the tone, could someone explain why the "subwoofer crawl" is of any value at all? There is no question that the location of the subwoofer is paramount, yet the "crawl" method relies on the notion that the subwoofer will sound/perform the same whether it is located at your LP or against the wall somewhere. Once you move the sub from your LP to the preferred location, based on your crawl test, it will perform differently, so I just don't get it. In mathematics ab = ba but I don't think it holds in subwoofer relationships lol.

 

[Digital_Thor]

I initially thought that 25-30 Hz was plenty low for music listening. But after tuning it flat to 20. I have to admit that everything just acquire a better and bigger level of music enjoyment.
I have 2 x 12" and 2 x 15"- all DIY. I found most commercial subs to be way too overrated and expensive. Easier in the end to just build something yourself.... when you of course can live with your own DIY look
What I then also learned.... is that bigger subs can have more dynamics and sense of "full-ness". But they don't necessarily play deeper. But with enough power and DSP - you can push them harder before things goes too bad.

Now that everything is tuned very smoothly and even. I enjoy the powerful dynamic sensation, even at low levels. There is only the bass that needs to be there and I like it like that - very neutral... maybe with a very slight 2 dB rise in the lower end.

I use 12" Scanspeak - like the old XXLS from peerless. And 15" Dayton RS390HF. All in closed boxes to simply keep it - well - simple. I would always go for something simple, rather than complicated - because the end result - the final acoustical sum and output - is what truly matters.

I think that the "fuss" started when people forgot to read the basics and skip all the BS that is so easily available everywhere.

You can buy the world's best subwoofer, but turn the wrong nob or interpret one measurement or setting wrong - and then you're never going to get good bass.

KISS

 

[NTK]

In mathematics ab = ba but I don't think it holds in subwoofer relationships lol.

It is based on the (Rayleigh's) acoustic reciprocity theorem.

Reciprocity in acoustics (Chapter 4) - Reciprocity in Elastodynamics

Reciprocity in Elastodynamics - February 2004

www.cambridge.org

It takes highly specialized nonlinear materials on the boundaries to "defeat" reciprocity.

https://cmdl.missouri.edu/papers/NRM.pdf

 

[dshreter]

In a film soundtrack a subwoofer is fed by the LFE channel. It is short for Low Frequency Effects. No effects, no sub output.

…unless utilizing bass management.