Midrange or Midbass in Kicks vs Doors

[DirtyBumOAK510]

As much as I've deep-dived these threads for answers, I still have questions. I'm not a pro, I still have a lot to learn. I'm going to cross-post this on DIYMA just because I have a few ongoing conversations over there.

I'll start with a couple of assumptions so this doesn't get too far off topic.
1. I'm assuming that the traditional method is Subwoofer behind you, mid-bass in well treated doors, and mid-range is somewhere else (dash, door, kick, etc).
2. I'm limiting this to a "mid-bass" (60-90hz HPF - ~300hz LPF), and a "mid-range" (~300hz HPF meeting a tweeter or HLCD).
3. We aren't worried about beaming, because we are crossing our mid-range below where it beams (lets just say something like 2000hz).
4. I'm trying to limit this to speaker positions for mid-bass and mid-range - kicks and doors. Nothing on the dash.
5. I'm assuming we have a well treated door, and I'm assuming we have a well made kick panel (few resonances, dampened, appropriately sized, etc)


I'll admit the fact that I'm using horns, so I don't have the same crossover issues (ie, high crossover) that Tweeters would normally have. I can cross my horns as low as 800hz. Partially as a result of this, beaming shouldn't (I'd like to stress the should) be an issue.

So here is the heart of my question. You have amazing (non-resonant) kick panels, and you also have super well deadened/treated doors. Where do you put the mid-bass? and where do you put the midrange? If they are the same speaker, where does it go? Mid-bass in the doors? and Mid-range with the perfect on-axis response in kick panels? Or Mid-bass in the non-resonant kick panels and the mid-range in the doors? Do you favor limiting all the resonances in the doors from the 50-90hz frequencies, or do you favor on-axis response from the mid-range (from a speaker that should be crossed over low enough to not have axis issues to begin with ... right?)?.

Personally, I think my doors can take a damn beating with mid-bass from my Stevens Audio MB-6s up into the 110 db area. the big BUT with using doors in this case though is that I get some crazy resonances and rattles coming from my door hardware and my window weatherstripping when pushed to those higher volumes. They get absolutely obnoxious ... but only with specific songs and specific frequencies. It's 5% of the time, but that 5% of the time really, to me, stresses the weakness of even a well treated door in dealing with a punishing mid-bass, especially in the frequencies at or below my 80hz crossover. 50-80hz just activates every weakness in terms of metal, plastic, wires, or whatever that just starts vibrating and making noise.

If I had a pure midrange in my door (playing from 300hz+ for instance), I'd have some issues with off-axis response, BUT I'd have a crossover well below the beaming frequencies of that speaker, so does it really matter? If my 6" speaker beams at 2000+hz, and my crossover is 1500, should I care what frequency it beams at? Am I missing something?

If I have a mid-bass (80-300hz?) in a well treated, non resonant kick panel, wouldn't that eliminate some of the door ****ery in terms of rattles, resonance, and general BS in dealing with a speaker playing inside an enclosure (really an IB) that is made up of a whole bunch of pieces of sheet metal, hardware, glass, wires etc?

Is the only reason to not have the mid-range not in the door (on the dash, pillars, kicks, etc) to be able to make it less off-axis? Or is it because it needs its own tiny sealed enclosure? Or what is it?

What am I missing in assuming that having midbass or mid-range in the doors vs kicks is interchangeable?

[geolemon]

Think about vibrations.

It's hard to do midbass in doors - and that's not just because all speakers trying to make bass really need enclosures to ideally do that. There's lots of stuff in your door that rattle and buzz- even if you have built enclosures inside those cavities, the unfortunate byproduct of doing a great job is that the kick of the bass is going to make for rattles and buzzes - especially when the speaker itself directly is shaking the door.

Now think about enclosures.

It's hard to do midbass in kicks, because there's not much room back there, and again - speakers that are trying to make bass not only need enclosures to ideally do that, but they need a significant amount of airspace to do it efficiently and effectively. Hoffman's Iron Law dictates that the smaller the enclosure, the less capable of making bass (low frequency extension) and the less loudness (lower efficiency) you will get.

There's other ways to do midbass - surprising ones, even.

Lots of horn installs in the 90's simply put the horns up front, and the midbass in the rear deck (sealed off to really be a proper baffle, if not proper enclosures) or rear factory locations modified to function effectively.
Lots of high-end horn installs and even 3-way installs put the midbass under the front seats, inside of slim enclosures under the seats.

There's other challenges that arise-
Lots of cars have a "midbass null" related to acoustics and reflections, things you really can't do anything about other than relocate or augment your midbass drivers. I had (well, stiil have, technically) a 95 Civic that was extremely difficult to get midbass, even if I had the beefiest midbass you ever saw, in enclosures, with hundreds of watts each. Just acoustics, cancellation - nulls.
And in my Civic's case, that really was directly tied to the midbass locations themselves. They set up that null. Moving them to a different location could resolve that issue.

I also own a 2017 Civic Hatchback that doesn't suffer that midbass null at all - even though the drivers are roughly in the same location, forward corner of the doors. Of course, I also have speakers in the rear of the 2017 where I don't in the '95 Coupe, so that could be part of that reason - but my point is, every car is different.

As far as on vs off-axis, that really entirely depends on how high you are planning to run it. Directionality is nearly entirely determined by your speaker's diameter - shape doesn't even matter. Once the frequency is high enough that the wavelength is smaller than the effective cone diameter, the speaker will start to beam - it'll become directional, where your off-axis response starts to fall.
But that's just one reason speakers are re-located or re-aimed. If it's just midbass, you probably don't have much to worry about. But if you are using them up into the midrange, you need to decide if that's going to drag your image down, or make one side too prominent, or just sound bad.

[DirtyBumOAK510]

Thank you for the insights.

I'm going to play around with some bags of packing foam and see how much space I can fit up front. Sealed 6-6.5" midrange would be easy peasy as they would only need .15-.3 cubic feet max. I have been modeling some of the 8" drivers I have (Beyma 8G40, B&C NDL51 - the QTC version has a higher fs, qts and almost half the mms as I found out, and some Stevens Audio MB8s.) All those 8" drivers really want to be in a .75-1 cubic foot enclosure, typically vented. That's one thing in the trunk but up front is quite a bit! I had modeled some 0.5 cubic feet enclosures that were ok, they would definitely need an 80hz+ crossover as they roll off naturally pretty quick.

My plan for the mid-ranges was to cross them before beaming (13500/6"/2) so approximately 1200hz. My horns currently are at 800hz so I think that's reasonable. If they end up in the kicks then they are certainly more flexible in terms of beaming.

I could go smaller on midrange but I don't think I really need to. 1200-2000hz being on a 6.5 seems ok to me. They have the added benefit of having some options with typical PA sensitivity to match up with the horns. The Ciare NDK6-1.5 is 98db and 18sounds has the 6NMB420 and 900 which are 97 and 98 db.

I'm still learning and trying to figure it out. I'm welcome to insights, questions or just general shit talking.

[nadams5755]

you could take the mikey approach: 10" pro audio midbass in ported boxed doors, 5-6" pro audio midrange in the kicks, and horns under the dash.

[DirtyBumOAK510]

Better late than never ...

I've been chatting with mikey about it. I don't think I can swing the doors yet. I recently was able to squeeze 8" high sensitivity mid-bass in there and 10" seems impossible. The biggest issue is all the rattles and resonances of the door. I've poked around my door to see whats rattling and between 60-125hz my door lock mechanisms and window trim come alive once the SPL meter gets high enough. It sounds great up until a certain volume. I don't think more energy from 60-125 is going to help that unfortunately. I'm not ready to go ported in the doors. 8" was a big step for me. 8" is also a physical depth limit for me. 3.5" is all I get before I have a speaker sticking out into my cabin and no longer hidden behind an already modified door panel.

I'm leaning more and more towards the 6.5"-8" midrange in the kicks. The good thing about horns is that currently I'm crossing them at 800hz, so I have a lot of wiggle room in terms of extending that crossover if I add a midrange. I can cross somewhere around where beaming starts. Recently I've been leaning towards higher efficiency options like Purifi's new "Preview" 6.5" (89db@1w), or Acoustic Elegance TD6M (93db@1w). Even the purifi should be able to put out 112db @ 256w for 200-2khz. But don't get me rambling about high sensitivity mids ... For the record I'm not into the SPL or SQL side of life, I'm just a huge fan of dynamic range and having everything sound good when it is time to turn up the volume.

P.S. I've seen you post in the CA SQ group on Facebook. I'm from Oakland but I don't get to get out to any of the events due to work and family. Car Audio is my guilty pleasure that I sneak in during the hours in when everyone is sleeping, napping, or out for the day. I'd love to hear your car sometime.

[nadams5755]

P.S. I've seen you post in the CA SQ group on Facebook. I'm from Oakland but I don't get to get out to any of the events due to work and family. Car Audio is my guilty pleasure that I sneak in during the hours in when everyone is sleeping, napping, or out for the day. I'd love to hear your car sometime.

if you can sneak away for a day, there's a couple meca events coming up in the bay area. montery/seaside 8/7 - https://mecaevents.com/events/2967. a bit closer to home in sept, there's CA state finals in modesto. https://mecaevents.com/events/3025

the latter event should have a bigger group and field of vehicles. state finals 4x should be upwards of 30 cars.

we have the occasional fritters and frequencies meet-ups on saturdays, they'll be posted on the CASQ group. kinda late notice though. they tend to be in east-bay like dublin/livermore.

[chithead]

This is an interesting read. Curious to read the results of your testing and experimentation.

Recently picked up a Jeep with the dash and overhead pods for speakers. The dash pods are way too small for a decent 6.5" - but DavidRam did something really cool and installed aperiodic vents into the rear of them for his 6.5" mids. I went the opposite, and determined since the overhead pods have more volume, to put the 6.5" there, and went smaller with a 5.25" in the dash pods. From the factory though, they are vented. Actually am debating on trying to retain the port, at least with the 6.5" pods. The output is quite impressive with them from the factory 4" speakers. Definitely has raised my curiosity with vented mid bass.

[goatpanda]

This is an interesting read. Curious to read the results of your testing and experimentation.

Recently picked up a Jeep with the dash and overhead pods for speakers. The dash pods are way too small for a decent 6.5" - but DavidRam did something really cool and installed aperiodic vents into the rear of them for his 6.5" mids. I went the opposite, and determined since the overhead pods have more volume, to put the 6.5" there, and went smaller with a 5.25" in the dash pods. From the factory though, they are vented. Actually am debating on trying to retain the port, at least with the 6.5" pods. The output is quite impressive with them from the factory 4" speakers. Definitely has raised my curiosity with vented mid bass.

Interesting, I didn't know the newer Jeep overhead pods looked like that. If you're curious to try vented midbass, the Silver Flute 4ohm 6.5 is a great candidate, that's what I'm using as my ported underseat midbass. They're cheap, surprisingly well-built and model great in tiny ported enclosures. Due to space constraints under the seats, I'm limited to ~0.145 cu.ft net with an external port that tucks under a seat bracket. Port tuning is around 70hz, with a 2" x 8-ish" port (I forget the specifics). I currently have them crossed at 78hz 24db. They don't play low, but they have really good sensitivity and output, very snappy midbass. With a larger enclosure and lower port tuning they would be able to dig deeper. You can see these weirdos on page 2 of my build thread: https://www.caraudiojunkies.com/show...le-Build/page2

[chithead]

Absolutely! Your build is one of the main reasons I'm seriously considering these ported mid bass enclosures.

[goatpanda]

Absolutely! Your build is one of the main reasons I'm seriously considering these ported mid bass enclosures.

Oh nice! If you can, maybe try to build something temporary to see if you like it or not. What works for me under the seats of a Golf might not work for you above your head in a Jeep. It would suck if you chopped up the factory pods, only to discover you hate it!