Use your subwoofer to get better midbass

[mauian]

Very cool video, Erin. And thanks for sharing your downfiring results jdunk (I will be trying that with my JL soon). I wonder if you are seeing that boost because you have effectively changed the length of the car (or the dimension it is measured in) as Erin referred to as the cause of the subwoofer null. My guess is that all the other positions you tried didn’t effectively change the “acoustic car length” as much as downfiring did?

I was wondering. Are these measured nulls (via RTA and mic) something that our ears/brains do NOT experience? As in, even though the dip is there in the acoustic response, our ears would tell us otherwise?

And related to this, is the pulling of the sound to the drivers side occurring because we have RTA’d the sides to match, and boosted the hell out of that speaker, causing us to hear it play much louder at say 80hz than the passenger side (when what we see on RTA is that they are level matched)? Just trying to make sure I understand what is occurring here...

Thanks!


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[dumdum]

Absolutely. Fun trick: mute all speakers. Now, un-mute a single speaker (doesn't matter which one). Now play a sine sweep through that single speaker. Listen how the sound will move from one side of the car to the other. It's a trip. But it's acoustics. If it can happen with one tweeter playing, it can happen with any combination of speakers playing.

normally it’s far worse with passenger side speakers as I believe the brain finds it easier to sort reflections from direct sound with the drivers side speakers, as the far side reflection is way longer than direct or near side reflections, whereas the passenger side speaker the difference between across the car to your ear is far closer to the length of direct or reflections from surfaces near the speaker, it’s amazing that people don’t think this happens

i explained it to someone the other day on a forum, I got told aiming doesn’t matter for mids... if you put more direct sound energy’s across a car the side window can then reflect more, careful aiming of speakers can very much effect speakers location to the ear

i think it’s all about balancing reflected sounds and reducing major reflections by using the pattern of off axis energy and balancing it to all surfaces it’s reflecting off of to enable the ear to locate the source of the sound more accurately, even if it’s not perfectly on the speakers location, as long as it can locate the source of sound at the majority of frequencies at a single point in space then your centre then becomes far more accurate and pin point as opposed to being diffused to some degree 👍🏼

it’s not so much that 10 degrees here or there will make a massive difference, as some people never move them far enough, generally I find there is a sweet spot that may be 10 degrees each way of up/down/left/right, outside this your gonna move it 15 degrees and never get a pinpoint stage due to energy bouncing everywhere, but if you find the sweet spot you certainly know about it, it’s the last 10 or 15 degrees when you put it in the sweet spot that makes the difference

by angling a speaker you move the radiation pattern by varying amounts at different frequencys, find the spot where the sound is most easily locate or at a single point while playing just that speaker, your centre and stage will thank you for it

i hope the above makes sense 👍🏼

[dumdum]

Very cool video, Erin. And thanks for sharing your downfiring results jdunk (I will be trying that with my JL soon). I wonder if you are seeing that boost because you have effectively changed the length of the car (or the dimension it is measured in) as Erin referred to as the cause of the subwoofer null. My guess is that all the other positions you tried didn’t effectively change the “acoustic car length” as much as downfiring did?

I was wondering. Are these measured nulls (via RTA and mic) something that our ears/brains do NOT experience? As in, even though the dip is there in the acoustic response, our ears would tell us otherwise?

And related to this, is the pulling of the sound to the drivers side occurring because we have RTA’d the sides to match, and boosted the hell out of that speaker, causing us to hear it play much louder at say 80hz than the passenger side (when what we see on RTA is that they are level matched)? Just trying to make sure I understand what is occurring here...

Thanks!


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the ear is very good at working out direct vs reflected sound if it’s far enough apart

i have experienced the very thing you are speaking of, you see a big peak on the rta, squash it and then it sounds flat, or have a dip and boost it, but it sounds awful and boomy, I believe it’s a scientific fact that the ear hears direct sound and can prioritise ‘listening’ to that and ignoring the reflections etc otherwise you’d kind of hear an echo almost, I am aware it’s not quite that simple, but then the brain and ears are very clever things, see my previous post...

for example in my car I get the same big peak at 150-300hz tapering off to 1khz, however it doesn’t sound muddy, or any kind of horrible like if the mids are placed at the wrong angle and position (getting the angles and position in the best possible place is the best way to start a system build, good locations make tuning far more simple!), the sound is then pulled here there and everywhere the edges of the stage are variable frequency dependant, ie hard left or right can move towards or away from the center of the car frequency dependant... when people say that some songs the stage is very wide past the mirrors, some songs are at the speakers or some are just inside the speakers it’s all about reflections and where the brain perceives the sound to locate, in a good system the sound located in a single spot (not nesc at the speaker, brains are funny like that) and that also makes the centre pinpoint accurate

[Pb82 Ronin]

Subbin! Good info here.

[Hillbilly SQ]

When people cross a speaker crazy low I wonder how many do it for bragging rights and little more?

[Mr Marv]

Excellent info as usual Erin and suddenly I find the fact that I prefer 5 1/4" mids in a 2 way hp'ed at 100hz with a low pass of 80hz on my sub has been giving me another benefit I wasnt aware of (many do not believe I am running 5 1/4's and a judge at comp once swore I had larger midbass drivers hidden somewhere in my El Camino ��)

[erinh]

And related to this, is the pulling of the sound to the drivers side occurring because we have RTA’d the sides to match, and boosted the hell out of that speaker, causing us to hear it play much louder at say 80hz than the passenger side (when what we see on RTA is that they are level matched)? Just trying to make sure I understand what is occurring here...

It depends on the resonance and what you’re listening to. The Q and frequency matter a lot. If you are listening to broadband music akin to pink noise then low Q resonances are more easily detectable. So, if you’re trying to tune with your ears using pink noise odds are you probably won’t notice sharp peaks/dips attributed to room modes. But if you’re listening to music with tones you will. I find this to be the case all the time and is why I use test tones for tuning below about 300/400hz.

And related to this, is the pulling of the sound to the drivers side occurring because we have RTA’d the sides to match, and boosted the hell out of that speaker, causing us to hear it play much louder at say 80hz than the passenger side (when what we see on RTA is that they are level matched)? Just trying to make sure I understand what is occurring here...

Nope, the null was there in my measurements even without RTA. And even with EQ applied, I never apply it to that null; if I don’t cross the subwoofer high enough to help fill it in (or if I cross the midbass below that null) it is easily detectable with the right music.

[mauian]

It depends on the resonance and what you’re listening to. The Q and frequency matter a lot. If you are listening to broadband music akin to pink noise then low Q resonances are more easily detectable. So, if you’re trying to tune with your ears using pink noise odds are you probably won’t notice sharp peaks/dips attributed to room modes. But if you’re listening to music with tones you will. I find this to be the case all the time and is why I use test tones for tuning below about 300/400hz.



Nope, the null was there in my measurements even without RTA. And even with EQ applied, I never apply it to that null; if I don’t cross the subwoofer high enough to help fill it in (or if I cross the midbass below that null) it is easily detectable with the right music.

Whoah. Ok, I think a portion of my mind just blew. So the music is being pulled to the driver side (the speaker with the null) for frequencies within the null region because...? (Resonance?)

Also, do you have a link to some good test tones you use for below 300/400? (Are these sine waves?) I’d love to try that out.

Thanks!


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[Cathul]

Thanks for the video Erin...

what i'm wondering now is, if i should try that as my left midbass seem to have the nulls at a complete different location.
See the attached measurement of the drivers response without any xover or eq applied.

Right now i tend to set the highpass at around 60-65 Hz based on that measurement as it would complement a LR24db alignment when simulated in REW AutoEQ.

[DavidRam]

Very interesting stuff, thanks!!

By chance my sub is going on the passenger side and down firing in my Jeep!! Whoop, whoop! Now the question is, do I pretend I'm a genius by planning it that way, or just admit it was dumb luck?!?! Lol