Never Put Subwoofers In Corners... Even with DSP and Multi-Sub Setups?

[FeddyLost]

Where are these magical listening rooms that are perfectly rectangular sealed enclosures I read so much about?

It depends on what exactly do you need from such room - noise isolation or accordance with theory.
Most of standard apartments in big houses are sufficiently rectangular, sealed and with massive walls.
Of course, perfect room can be excavated in solid rock and closed by big stone, but reinforced concrete floor and ceiling with walls from white silicate bricks are very similar.

 

[Harmonie]

Or ... live in a church

 

[Lbstyling]

Or ... live in a church

Yup. Just what you need...... 10hz flat....'can really feel the presence of God here!'

 

[Chromatischism]

It depends on what exactly do you need from such room - noise isolation or accordance with theory.
Most of standard apartments in big houses are sufficiently rectangular, sealed and with massive walls.
Of course, perfect room can be excavated in solid rock and closed by big stone, but reinforced concrete floor and ceiling with walls from white silicate bricks are very similar.

I'll just add that while you can get great bass by using multiple subwoofers and EQ in a small room with hard walls, that doesn't help from your crossover point up to the transition frequency. Generally, the least problematic bass will come from a larger room or one with softer walls.

 

[Trdat]

1. Hands down subs are the best upgrade one can do, going dual is the next best and probably an even better upgrade than a single sub. Going 4 also provides a step up but not as massive as going dual.

2. Getting an acceptable decay rate(mine is .2 sec a lot of treatment) also plays a massive role in bass response and tightness, treatments does help in achieving this, how much it can help with bass depends on the condition of your room in the first place. I tend to agree that dual or 4 subs does help with modes.

3. Love putting Subs in corners, get more of a thump. I also get a perfect bass boost with a 4pi response right where i need it in my sealed sub and an increase in sensitivity.

4. EQ ruins that special roll off of the sub that your enjoying or not enjoying, that said EQ can also give you that roll off to find that transients or type of bass your after. Personally, when it comes to dance music transients is key and I never EQ cause my sealed gives me the most perfect bass, with other music genres EQ it's fine to oomph up the bass cause you wont get overhang from the recording itself. (I've noticed that this concept hasn't floated around in this forum but explained well it makes sense) Essentially, you improve transients only by cutting off the lower frequencies or reducing there db that said you still need a good sub and large cabinet to reap the benefits of a decent sub.

 

[win]

People always talk about 2 or 4... I'm considering 3. I am debating a cylinder type sub that I can hide in an odd area of my listening room. The beauty of bass is you can hide it almost anywhere...

 

[FeddyLost]

Getting an acceptable decay rate(mine is .2 sec a lot of treatment)

In LF it's very troublesome even in dedicated room. Few subs is more acceptable for most of families than effective treatment.

 

[Trdat]

In LF it's very troublesome even in dedicated room. Few subs is more acceptable for most of families than effective treatment.

Totally agree but I would say treatment helps and tackles a few other issues as well. I mean it ultimately depends on what you can afford and the aesthetics. But 4 subs can take up as much as room as basic treatment and cost just as much. In saying that, cause LF is troublesome like you mentioned the more effective solution is the few subs options.

My apartment has horrible dips even after dual subs and a decay of .2 but the bass is tight and punchy.

 

[FeddyLost]

My apartment has horrible dips even after dual subs and a decay of .2 but the bass is tight and punchy

So these dips must be due non-modal interference issues if your decay in bass really ~ 200 ms.
Are they really audible?

 

[Trdat]

So these dips must be due non-modal interference issues if your decay in bass really ~ 200 ms.
Are they really audible?

I've been researching this topic heavily for a while now, but still have lot to learn so excuse my misunderstandings. But I got a dip at around 40hz and I am guessing that is related to the size of the small apartment must be a quarter wavelength thing and another at 80hz on the one side still haven't figured out where its from. But from my understanding you can't absorb the lower frequencies to the point where you get a flat frequency response the goal is just to get a decent decay.

I do admit that something is missing in the lower bass notes but like i mentioned I don't EQ dance music cause I get clean tight bass that starts and stops on a dime. When I do eq yes I get improvement but loose the transients. In terms of what is audible, I would say no, I got a pretty mean LF response with a thump right in your chest, I crossover at 180hz and no boominess. I am considering my next upgrade for subs to be horn loaded as I am searching for that sub that will give me even more slam and punch.

 

[Chromatischism]

4. EQ ruins that special roll off of the sub that your enjoying or not enjoying, that said EQ can also give you that roll off to find that transients or type of bass your after. Personally, when it comes to dance music transients is key and I never EQ cause my sealed gives me the most perfect bass, with other music genres EQ it's fine to oomph up the bass cause you wont get overhang from the recording itself. (I've noticed that this concept hasn't floated around in this forum but explained well it makes sense) Essentially, you improve transients only by cutting off the lower frequencies or reducing there db that said you still need a good sub and large cabinet to reap the benefits of a decent sub.

I'm not sure what you're getting at here. If you are suggesting that sound quality improves with less bass extension, that is the opposite of what most people find.

 

[Trdat]

I'm not sure what you're getting at here. If you are suggesting that sound quality improves with less bass extension, that is the opposite of what most people find.

I'm not suggesting sound quality improves, but the transients improve. For me transients is sound quality for others the low extension is. The lower you go in bass frequencies the slower they are, essentially by making a sealed cabinet the roll off is as such that your reducing the bass frequencies compared to the shallower roll off but lower extension of a ported sub.

Once you EQ you lose that roll off, totally changing the transient capability which is something me as an amatuere had no idea about. After experimenting and further reading once you compare similarly EQ subs regardless of ported or sealed they sound about the same. Now, I am not an expert and not sure if science backs this but a few leaders in the industry swear by this idea and my experience tends to believe it. I personally never EQ if I need the transients and prefer treatment and multiple subs.

I will add that on most music, transients don't play a major role, with dance music it does the overhang kills the bass. But again for me, the more transient the more thump your getting. So my original posts point was that this idea of EQ is never spoken about on this forum its a blessing but also a pest if you don't know the disadvantages. Lastly, transients is key to getting good bass whether it comes from sub itself or the decay of the room or a combination of these factors.

 

[Chromatischism]

I'm not suggesting sound quality improves, but the transients improve. For me transients is sound quality for others the low extension is. The lower you go in bass frequencies the slower they are, essentially by making a sealed cabinet the roll off is as such that your reducing the bass frequencies compared to the shallower roll off but lower extension of a ported sub.

Once you EQ you lose that roll off, totally changing the transient capability which is something me as an amatuere had no idea about. After experimenting and further reading once you compare similarly EQ subs regardless of ported or sealed they sound about the same. Now, I am not an expert and not sure if science backs this but a few leaders in the industry swear by this idea and my experience tends to believe it. I personally never EQ if I need the transients and prefer treatment and multiple subs.

I will add that on most music, transients don't play a major role, with dance music it does the overhang kills the bass. But again for me, the more transient the more thump your getting. So my original posts point was that this idea of EQ is never spoken about on this forum its a blessing but also a pest if you don't know the disadvantages. Lastly, transients is key to getting good bass whether it comes from sub itself or the decay of the room or a combination of these factors.

So low bass frequencies are not actually slower, but I think I know what you're getting at. There is something known as a "masking effect" that happens. Basically, strong low bass can mask detail in the mid and upper bass, even though it's still objectively there. Another way to think about it is that a lack of low bass emphasizes mid and upper bass - which is why people believe sealed speakers and subwoofer sound "tighter". It's all perception.

On a related note, this is one of the reasons why I use tuneable subs like Rythmiks. You can change the sound at the flip of a switch.

 

[Trdat]

So low bass frequencies are not actually slower, but I think I know what you're getting at. There is something known as a "masking effect" that happens. Basically, strong low bass can mask detail in the mid and upper bass, even though it's still objectively there. Another way to think about it is that a lack of low bass emphasizes mid and upper bass - which is why people believe sealed speakers and subwoofer sound "tighter". It's all perception.

On a related note, this is one of the reasons why I use tuneable subs like Rythmiks. You can change the sound at the flip of a switch.

Exactly. When many used to say there is no such thing as fast bass I was offended because I changed my subwoofer by reducing the QTC over 3 stages from .7 to .61 to .42 and I saw the transients improve, I was like its there I can hear the difference. But like you said it's all a perception and I found that out when I turned on my convolution with Audiolense and it totally mucked up the bass. I was under impression EQ was going to even out some of the room modes and help flatten the frequency but no way made it worse. Of course this had nothing to do with Audiolense its just when you EQ your losing what a sealed sub is all about.

Now, I would love to know if made a midrange cab or even a subwoofer with a roll off similar to a ported then EQ'd it to a sealed roll off how would that play out? Does what I am saying work the other way around. Can the EQ to give it the transients you're missing?

Let's say for example my PA cab plays down to 100hz and I made a ported alignment then used a active crossover to lowpass the subs would the transients become like a sealed sub due to the 24db roll off?

 

[patate91]

So low bass frequencies are not actually slower, but I think I know what you're getting at. There is something known as a "masking effect" that happens. Basically, strong low bass can mask detail in the mid and upper bass, even though it's still objectively there. Another way to think about it is that a lack of low bass emphasizes mid and upper bass - which is why people believe sealed speakers and subwoofer sound "tighter". It's all perception.

On a related note, this is one of the reasons why I use tuneable subs like Rythmiks. You can change the sound at the flip of a switch.

Bass is not slower but it decays slower rooms. Slow decaying bass gives muddy and one note bass. This is why it's important to look at RT, waterfall, etc. graphs too.

 

[Chromatischism]

Of course this had nothing to do with Audiolense its just when you EQ your losing what a sealed sub is all about.

I don't agree with this at all. I've done lots of EQ with sealed subs and haven't lost anything, only gained sound quality.

If you used EQ to match the response shape and overall Q of two otherwise equal sealed and vented subs, they would have the same transient response.

 

[Trdat]

I don't agree with this at all. I've done lots of EQ with sealed subs and haven't lost anything, only gained sound quality.

If you used EQ to match the response shape and overall Q of two otherwise equal sealed and vented subs, they would have the same transient response.

Interesting.

Can you tell me the QTC of your sealed sub perhaps the difference was not much so the you didn't feel that there was a degradation in the transients?

 

[Chromatischism]

Interesting.

Can you tell me the QTC of your sealed sub perhaps the difference was not much so the you didn't feel that there was a degradation in the transients?

Q is variable, but is effectively 0.1-0.5

 

[Trdat]

Q is variable, but is effectively 0.1-0.5

Thats tight. And you didn't feel a difference, interesting.

I know for a fact that there has been blind tests on similar EQ'd roll offs on different subs and no one was able to tell the difference. But, I have to find them as I was told about it and never went searching.

That said, when I experimented I usually do these tests at loud volumes perhaps the driver was overshooting. But I am convinced that the transients was totally lost once a convolution was in play.

 

[sigbergaudio]

Exactly. When many used to say there is no such thing as fast bass I was offended because I changed my subwoofer by reducing the QTC over 3 stages from .7 to .61 to .42 and I saw the transients improve, I was like its there I can hear the difference. But like you said it's all a perception and I found that out when I turned on my convolution with Audiolense and it totally mucked up the bass. I was under impression EQ was going to even out some of the room modes and help flatten the frequency but no way made it worse. Of course this had nothing to do with Audiolense its just when you EQ your losing what a sealed sub is all about.

Now, I would love to know if made a midrange cab or even a subwoofer with a roll off similar to a ported then EQ'd it to a sealed roll off how would that play out? Does what I am saying work the other way around. Can the EQ to give it the transients you're missing?

I'm not sure that what is happening here is what you think is happening. All small, DSP-enabled sealed subs today come with EQ applied from the factory to give the magic low end extension that would otherwise be impossible in a small, sealed configuration. Done correctly, this does nothing to destroy or diminish transient response.

You also seem to imply that EQ can't be applied to sealed subs to even out room modes without somehow making it sound worse(?), which also isn't true.