Total Midbass Confusion

[cvame 0]

Hello guys, new to this forum. Im in search of good midbass to fill between my mids and sub. Ive read many many many posts and articles on midbass, here and on a lot of other car audio forums. I am not an electrical engineer/car audio guru of any sorts, but i like to do my own installs. It seems to me that the subject of midbass is the most difficult to understand for us "noobs". Most threads start simple "with what is a good midbass driver" then goes into a debate with the much more advanced audio guys on octaves, peaks, kiple ratings , Q's, Vas, etc... I realize that saying "brand x driver is definately what you need' is impossible to do with all variables involved in todays car audio. Does any one know where a "midbass-challenged" person like myself can go to get remedial-preschool level explinations? Or advice on my level of install? I like SQ but not a total audiophile, just want well rounded sound. Im not going to enter any sound challenges or anything. lol

Sorry to muddy up the waters here with such a noobie question, but hey we are all noobies at some point in time, right?

Thank you

[ssh 924]

Im in the same boat

[KU40 173]

You are in the right place to start. If you have any specific questions, ask them.

[DeadlyMelody 0]

It helps to know what your budget is, the vehicle your putting this in, and what you have in your system already.

[cvame 0]

It helps to know what your budget is, the vehicle your putting this in, and what you have in your system already.

Sure, its a 2004 Ford F250 Superduty Crew Cab. I currently have Fosgate Power components with a 4 channel amp, and Two Fosgate 10' subs with a 600 watt momo block. Im considering adding another 2 channel amp to power two 8" midbass drivers in the front doors to fill in the noticable gap between the mids & subs. Since Fosgate doesnt make midbass drivers, ive been considering JL ZR800's. But ive seen alot of threads where people are using brands ive nevr heard of, nor know where to find them. Brands like "Peerless, CDT, Anarchy, Seas". They all have different capabilities, but how do they compare to a JL Audio ZR800? Because the price difference in these other brands is too good to pass up.

Thank you

[ulrisa 26]

I think the best place to start is to deaden your doors. Seal all of the holes (except the drain hole). It adds A LOT of midbass. Then I would start working with drivers. I love my Ascendant Audio Carbon Fiber Mids, but they are all I have experience with. If you can, try aiming the speakers in different directions and see what you like. I personally like them aimed towards the opposite passenger's ear level. Also, I've heard changing the phase and timing (I don't have that capability yet) can reduce a lot of cancellation so midbass will be a lot louder and such.

Hope this helps.

[Impious 1,476]

The remedial version is this: All of those factors you mentioned can't be ignored. They all need to be considered when selecting a driver. How much and how important different factors are is going to depend on different variables. The skinny is that if you are not a discerning audiophile, chances are good we could toss out a selection of 5 drivers, you could pick your favorite based on aesthetics alone (Ooh, that one looks pretty!) and you would end up a happy camper.

However, I would want to find out more about your current installation, setup and equipment before recommending you spend money and time installing midbass drivers.

Where are your current speakers installed? Do you have sound deadening applied? What are your current speakers (not just brand, but model)? What are your current crossover settings for the mids and subs? What subwoofers are you using? What do you feel you system is "missing"? What headunit are you using, and does it have any equalizer adjustments?

[smashedz28 110]

im tuned in here.

[ssh 924]

Not to threadjack but it's related, How important is the position/placement of midbass drivers? Can they be put in small sealed enclosures behind the driver and passenger seats?

[cvame 0]

Where are your current speakers installed? Do you have sound deadening applied? What are your current speakers (not just brand, but model)? What are your current crossover settings for the mids and subs? What subwoofers are you using? What do you feel you system is "missing"? What headunit are you using, and does it have any equalizer adjustments?

Sure no problem. Thanks alot guys, i really appreciate all the help with this.

Head Unit: JVC KW-XG700, with 3band eq and a sub setting.

Im currently shopping to an upgraded deck like Alpine,Kenwood or Pioneer.

Components Front&Rear: Fosgate Power T1652-S {100rms} - Powerd by an Infinity Reference 475A {75rms X4} (soon to be replaced by a Fosgate Power T600-4 @100rmsX4)

The speakers are crossed over with the supplied crossover box, i honestly dont know what frequency that is. The front set are in the factory door locations with the tweeters in the door "A"wing panel-on axis. The rear set is in the rear quarter panel stock locations, with the tweeter next to the 6.5" faceing forwards.

Subs: Two Fosgate Punch P2 10" 4ohm single voice coil (due to shallow depth) wired parallel - Powered by a Fosgate Punch 600.1bd mono block.

Subs are behind the rear bench seat in a very sealed box 3/4"mdf built to Fosgates specs. I have the crossover on the amp turned to "250" because any lower makes the gap even more obvious.

Misc. Info: I have not yet deadened the doors. I was going to during the door pod build. I added a line driver because the JVC pre amp was'nt putting out enough power, i had to trun the gains all the way up. I also had to add 2 ground loop isolators, even after moving patch cables far away from power wires.

What my system is missing is midbass, there is a distinct gap between the mids & sub bass. Its the bass that you can hear from a good pair of properly installed 6x9's- if that makes sense? Deep vocals, bass drum kick?

My hope is to make some front door pods and install some 8" midbass drivers (along with the 6.5" mids, sealed pod if needed) I can also get a nice 2 channel amp to power them off the split front channel or mono? If it does the trick ill get two more and put them in the back doors too, with a 4 channel amp. Either way, sitting up front in a crew cab you can hear the gap (or void) better than in the back closer to the subs. Or am i just crazy??

Does this information help? Again thank you guys for the replies...

[Impious 1,476]

Not to threadjack but it's related, How important is the position/placement of midbass drivers? Can they be put in small sealed enclosures behind the driver and passenger seats?

Long subject. Unimaginably long subject. I'll try to condense it down into a digestible version.

We localize midbass in the lateral plane only (i.e. left to right). We don't localize it on a vertical plane (high and low), and we don't localize it "front to back".

Midbass is localized by way of what's known as Interaural Time Difference (ITD). That is, the brain localizes midbass laterally due a difference in the time arrival of the sound wave between the left ear and right ear. ITD dominates our localization ques in the frequency bandwidth where the wavelengths of the soundwave are longer than the distance between our two ears. Generally the more ITD you can generate, the wider the potential imaging.

From this very basic knowledge, a couple things can be extracted. First, any midbass location that results in identical ITD will be indistinguishable to the ear....above your head, below your head, in front of you, behind you, it doesn't matter......as long as the ITD stays the same, your ears and your brain won't know the difference. Second thing we should notice is that worst location for a midbass is at a location that results in an ITD of zero; that would be directly in front of you, direct behind you, or directly above you. Related to this, since "imaging" in the lateral plane is a function of ITD, the "best" midbass location is a location that results in maximum ITD (i.e. the wider you can get the speakers, the better).

Now, a few caveats to this:

First, hearing rattling/buzzing/etc as a result of the midbass speakers exciting panel resonances (door panels, etc) or other noises will ruin the illusion. Second, the speakers must be operated within the bandwidth where ITD is the mode of localization. If you operate the driver outside of this bandwidth (this includes driver distortion, etc), then other factors will begin to contribute to our localization of the sound. Proper time alignment of the midbass drivers will need to be maintained with the other drivers in the system as well as between the midbass drivers themselves. Lastly (I think lastly, I'm typing this up semi-quickly), this does not take into consideration the effects of other factors such as reflections or other anomalies.

In the midbass region, the physical aiming of the driver doesn't matter. The wavelengths are very large in comparison to the diameter of the cone. What this means is that the frequency response on-axis and off-axis is going to be identical. You don't need to worry about trying to aim the drivers at the listener or anywhere in particular. There is going to be no difference in response between being directly on-axis and 60* off-axis, for example. Drivers operating within a bandwidth where the sound is non-directional (i.e. no difference between on-axis and off-axis sound) are said to be in their "piston range".

So, what did we learn from this very brief primer to midbass? Yes, you can mount midbass drivers behind you....your brain doesn't know the difference. Mount the drivers as wide as possible to maximize ITD. Aiming the drivers doesn't matter.

[ssh 924]

Not to threadjack but it's related, How important is the position/placement of midbass drivers? Can they be put in small sealed enclosures behind the driver and passenger seats?

Long subject. Unimaginably long subject. I'll try to condense it down into a digestible version.

We localize midbass in the lateral plane only (i.e. left to right). We don't localize it on a vertical plane (high and low), and we don't localize it "front to back".

Midbass is localized by way of what's known as Interaural Time Difference (ITD). That is, the brain localizes midbass laterally due a difference in the time arrival of the sound wave between the left ear and right ear. ITD dominates our localization ques in the frequency bandwidth where the wavelengths of the soundwave are longer than the distance between our two ears. Generally the more ITD you can generate, the wider the potential imaging.

From this very basic knowledge, a couple things can be extracted. First, any midbass location that results in identical ITD will be indistinguishable to the ear....above your head, below your head, in front of you, behind you, it doesn't matter......as long as the ITD stays the same, your ears and your brain won't know the difference. Second thing we should notice is that worst location for a midbass is at a location that results in an ITD of zero; that would be directly in front of you, direct behind you, or directly above you. Related to this, since "imaging" in the lateral plane is a function of ITD, the "best" midbass location is a location that results in maximum ITD (i.e. the wider you can get the speakers, the better).

Now, a few caveats to this:

First, hearing rattling/buzzing/etc as a result of the midbass speakers exciting panel resonances (door panels, etc) or other noises will ruin the illusion. Second, the speakers must be operated within the bandwidth where ITD is the mode of localization. If you operate the driver outside of this bandwidth (this includes driver distortion, etc), then other factors will begin to contribute to our localization of the sound. Proper time alignment of the midbass drivers will need to be maintained with the other drivers in the system as well as between the midbass drivers themselves. Lastly (I think lastly, I'm typing this up semi-quickly), this does not take into consideration the effects of other factors such as reflections or other anomalies.

In the midbass region, the physical aiming of the driver doesn't matter. The wavelengths are very large in comparison to the diameter of the cone. What this means is that the frequency response on-axis and off-axis is going to be identical. You don't need to worry about trying to aim the drivers at the listener or anywhere in particular. There is going to be no difference in response between being directly on-axis and 60* off-axis, for example. Drivers operating within a bandwidth where the sound is non-directional (i.e. no difference between on-axis and off-axis sound) are said to be in their "piston range".

So, what did we learn from this very brief primer to midbass? Yes, you can mount midbass drivers behind you....your brain doesn't know the difference. Mount the drivers as wide as possible to maximize ITD. Aiming the drivers doesn't matter.

thank you Impious for that, this is one of those things i'll be copying and saving on my computer for future reference.

[cvame 0]

@ Impious Thats very interesting. Not to hijack my own thread (if thats possible, lol) does the same theory apply to sub bass as well? If yes, then my system must be totally screwd up because when sitting in the front seats of my crew cab, its obvious the bass sound is comming from the rear. Is that due in part to the large cabin space ,or is my imaging off that bad? Could this be why i crave midbass so bad?

[Cant Get Enough 6]

Your hearing the direction of the subs becauseyour crossed over too high, delving into the cloudy frequencies which actually cover the midbass your speakers are producing. I have a recording studio and must clean between 150 to 400 Hz (cut too much and your sound can become thin) on most if not all bass instruments to allow the mid and sub bass to envelope the listener not to distinguish direction. Providing clean rich bass. I have T1652-s front, T154's rear on a T6004 and get excellent results with all the midbass I nedd supplemented with a pair of P3's on a T6002 providing all missing sub frequencies. I also along with my passive crossover on the T1652-s I shelve them at 80 Hz

On another note bass frequencies are between 25 to 300 Hz wher the midbass lies between 120 and 150 Hz so I wouldn't set a subwoofer crossover any higher than 150 Hz and I personally set mine at 100 Hz leaving my 6.5 to handle the rest but if you really want lo add, try a single 8" and cross it over cutting 60 Hz and lower and 150 Hz higher and set the gain too fill out the midbass but not too much so you dont muddy the overall sound

Edited June 29, 2010 by Cant Get Enough

[cvame 0]

Thank you "cant get enough". After reading countless posts on this stuff for the past 3 weeks i can almost understand everything you said. lol. I have my subs at the 250 number on my amp because thats where it sounded good. Im still trying to fully understand the Hz numbers related to what effect it has. Thank you for explaining that midbass is between 120-150 Hz. Ive been told midbass is between 60 - 500Htz before, which i thought was kinda big gap. Is there a chart somewhere that i can see that shows what the Hz ranges are for each type of sound? (highs-mids-midbass-sub) That would help me alot., because all i do now is switch the button on the amp to"HP,AP, or LP" depending on the speaker and then turn the crossover knob till it sounds good.

On your T1652-S, did you use the crossover that came with them? All i did was wire the supplied crossover in line and set the amp to "all pass".

I also have mine in the door IB , with no dynamat yet. You think thats a possible problem?

I really appreciate the advice.

[Cant Get Enough 6]

Thank you "cant get enough". After reading countless posts on this stuff for the past 3 weeks i can almost understand everything you said. lol. I have my subs at the 250 number on my amp because thats where it sounded good. Im still trying to fully understand the Hz numbers related to what effect it has. Thank you for explaining that midbass is between 120-150 Hz. Ive been told midbass is between 60 - 500Htz before, which i thought was kinda big gap. Is there a chart somewhere that i can see that shows what the Hz ranges are for each type of sound? (highs-mids-midbass-sub) That would help me alot., because all i do now is switch the button on the amp to"HP,AP, or LP" depending on the speaker and then turn the crossover knob till it sounds good.

On your T1652-S, did you use the crossover that came with them? All i did was wire the supplied crossover in line and set the amp to "all pass".

I also have mine in the door IB , with no dynamat yet. You think thats a possible problem?

I really appreciate the advice.

I use the crossovers supplied for the speakers for controlling the frequencies between the 6.5's and the tweets then my HU has a high pass shelf which I set at 80 Hz cause 55 Hz for the passive is a little too low for the gain level I wan't to set with my T6004 that I set too all pass but if you dont have an HU with a shelf you could use the amps crossover. Sound dampening will always make things better (not crucial though). Above 150 to about 500 hz is the cloudy/muddy range in the spectrum which I learned while studying recording but also makes the mix fat or thick not enough will make your music sound thin fine line between too much and not enough. If you've ever noticed certain CD's make you want to turn the treble up or down this is usually cause of a engineer's bad mix in this frequency range.

here's from one of my books highs = above 3.5 Khz mids= between 250 Hz and 3.5 Khz Lows= below 250 Hz

and these are divided into 8 subcatagories ( sub bass "rumble" = below 60 Hz ) ( bass "thump"=60 to 120 Hz ) ( mid bass "roundness"= 120 to 150 Hz) ( high bass "fullness or muddiness"= 150to 250Hz) (lower midrange "the Oohzone" = 250 Hz to 1.5 Khz) ( upper midrange "projected"= 1.5 to 3.5 Khz ) (highs "presence or piercing""= 3.5 to 6 Khz) ( high highs "brilliance or searing"= above 6 Khz)

Edited June 29, 2010 by Cant Get Enough

[cvame 0]

Thanks a Million "Cant get enough"!!!! That is just what i needed to get a better understanding, It cleared up so much for me. So when someone says "cross those over at 120-150Hz", i turn the knob back & forth between those numbers only, right? So when you set a speaker at a certian crossover number, say 120HZ, does it only allow frequencys from 120 and below only? Or 120 and up? Or does it only allow the frequencys at 120 to pass?

Sorry for so many questions at once, but ive had a car audio break through lol.

Thank you again!

[ssh 924]

depends if its a low pass filter (lpf) or high pass filter (hpf), lpf allows hz below filter to pass and reduces the higher frequencies. hpf does the exact opposite, allows higher frequencies to pass and reduces lower frequencies.

[cvame 0]

Aaahh OK, Thats what i believed them to do but wasnt sure. Thank you for explaining that. Does same go for mid-range & mid-bass levels too? I mean what keeps a midbass driver set at say "130Hz" from running the low sub frequencys like 30Hz that could damage them?

Edited June 29, 2010 by cvame918

[cobra93 47]

You need a band pass crossover ( a high pass and low pass crossover working in combination with each other = the pass band or band pass ) .

This will allow you to control the frequencies you are sending to the speakers in question, in your situation mid bass speakers.

The crossover(s) could be on your head unit, a stand alone crossover or on your amplifier.

Your sub amp may have a subsonic or infrasonic filter, this will pass frequencies higher than what you set it at to your sub, while the low pass filter ( set at 250 hertz on yours ) will send frequencies lower than than 250 hertz to your sub.

That is a very general description, not taking into account the order of the x-over slope, or the fact that the freq. you set it at (on the amp) is "x" decibels quieter due to the slope of the x-over.

I hope I didn't screw you up on that last sentence.

[Impious 1,476]

Your hearing the direction of the subs becauseyour crossed over too high, delving into the cloudy frequencies which actually cover the midbass your speakers are producing. I have a recording studio and must clean between 150 to 400 Hz (cut too much and your sound can become thin) on most if not all bass instruments to allow the mid and sub bass to envelope the listener not to distinguish direction. Providing clean rich bass. I have T1652-s front, T154's rear on a T6004 and get excellent results with all the midbass I nedd supplemented with a pair of P3's on a T6002 providing all missing sub frequencies. I also along with my passive crossover on the T1652-s I shelve them at 80 Hz

On another note bass frequencies are between 25 to 300 Hz wher the midbass lies between 120 and 150 Hz so I wouldn't set a subwoofer crossover any higher than 150 Hz and I personally set mine at 100 Hz leaving my 6.5 to handle the rest but if you really want lo add, try a single 8" and cross it over cutting 60 Hz and lower and 150 Hz higher and set the gain too fill out the midbass but not too much so you dont muddy the overall sound

I can't say I've ever seen a broadly accepted definition for "midbass". Just a simple google search for the definition of midbass results in 3 different frequency ranges from 3 different sources. The definition of "midbass" is going to vary depending on the source. There's no authority, that I'm aware of, that can or has defined the "official" range of frequencies that encompasses "midbass". Everyone's opinion and definition will vary. And just an FYI to others, when most people on the forums are discussing "midbass", as well as most manufacturers in our hobby, they are not talking about such a narrowly defined range.

Here are the google search results;

Definitions of midbass on the Web:

• An area of the low frequency range, usually represented from approximately 80 to 500 Hz.
  www.htsa.com/glossary.aspx
• The middle of the bass part of the frequency range, from approximately 50 to 100 Hz (upper bass would be from 100 to 200 Hz). Also used as a term for loudspeaker drivers designed to reproduce both bass and midrange frequencies.
  www.eliteavi.com/hometheaterglossary.html
• The audio frequencies just above the Sub-bass range from around 100Hz up to 400Hz.
  www.wantsound.com/glossary.htm

Regardless, our identification of sound and localization cues has little to do with what frequency range we arbitrarily define as being "midbass", and everything to do with the wavelength of the frequencies in relation to the dimensions of our head and the physiology of human hearing. If the slope of the crossover is decently steep, a subwoofer with a crossover point of 250hz should be pretty well within the realm of what I described above. That said, I wouldn't recommend a 250hz crossover point for a subwoofer for a number of other reasons.

Without hearing the system, there are a number of reasons why the subwoofer might be obviously identifiable as being "behind" you. First would be any rattles/buzzing/humming/etc that may be coming from panels behind the listener. Second would be any mechanical noises that subwoofer might be producing. Third would be tactile sensations....for example, feeling the vibration of the back of the seat. That's a quick but certainly not comprehensive list of a few reasons.

[Impious 1,476]

I use the crossovers supplied for the speakers for controlling the frequencies between the 6.5's and the tweets then my HU has a high pass shelf which I set at 80 Hz cause 55 Hz for the passive is a little too low for the gain level I wan't to set with my T6004 that I set too all pass but if you dont have an HU with a shelf you could use the amps crossover.

There is a specific type of filter that is called a "shelf", and it is different than a standard HPF or LPF. I would be seriously surprised if your HU included an actual shelf filter. In fact I'd be very interested in know what HU that was as I don't know of any, and very few car audio processors actually have shelving capabilities.

The graph of a standard HPF or LPF look like a gently rolling hill; a shelf filter looks like, well, a shelf (hence the name).

[Impious 1,476]

Ive been told midbass is between 60 - 500Htz before, which i thought was kinda big gap.

Depends on who you talked to

I wouldn't have many qualms with that range being loosely defined as "midbass".

Is there a chart somewhere that i can see that shows what the Hz ranges are for each type of sound? (highs-mids-midbass-sub)

There isn't a universal chart that everyone in the audio industry uses to define those ranges. They are fairly arbitrary and specific to whatever source you are referencing. 120-150hz is by far the most narrow I've seen, and nobody else in this hobby is going to use such a narrow definition. So don't get confused when people on the forums or manufacturers use a completely different (and less stringent) definition for "midbass". There was actually another thread not long ago on this exact topic; What is considered Mid Bass? - SSA Car Audio Forum

So when someone says "cross those over at 120-150Hz", i turn the knob back & forth between those numbers only, right?

It depends on their reasons for saying that. There are some good reasons, and some not so good reasons.

First and foremost, there is no set rules when it comes to setting crossovers in car audio. Well, I take that back....there is one rule. That rule; Set them to where ever sounds best. It's that simple. Really, that simple. No one on the internet can tell you where to set your crossovers points, there's far too many factors involved that can't be adequately analyzed over the internet. It's just not possible. There are a few caveats to this ofcourse. One would be the potential for physical damage to the driver due to overexcursion....this can be analyzed pretty well from modeling the drivers and noting their excursion over the bandwidth at a given power level. The other would be distortion. If a driver has been properly measured to exceed acceptable distortion performance, then crossing the driver so that it stays out of this range would be desirable. But pretty much, outside of that, it's whatever sounds best to you in your system.

So when you set a speaker at a certian crossover number, say 120HZ, does it only allow frequencys from 120 and below only? Or 120 and up? Or does it only allow the frequencys at 120 to pass?

Crossover Slope Basics

Read the link. If it's still unclear, feel free to ask and we can fill in the gaps.

[Impious 1,476]

Well, this thread got a bit sidetracked.

Back tracking to your original question; I would first try solidifying the installation of your current mids before adding any additional speakers. You will want to seal any holes in your inner door to properly isolate the front wave from the back wave of the mid. Sound dampening the door to reduce rattles and resonance can be helpful as well to enhancing performance in the midbass.

I may have missed it, but where are your speakers currently highpassed?

[cvame 0]

I think my car audio break through was just broken up...lol No, im hanging on the best i can with you guys. I really appreciate the lessons, thank you. Im sure that there are others reading this that are in the same boat as me but were afraid to ask such remedial questions.

So if i set the amps crossover to 150, and set the amp filter to "LP", the speaker will play 150Hz down to 30Hz? And if i set the amp filter to "HP", then the speaker will see 150Hz up to 3.5Khz?

And to keep my midbass in a certian range like say 150-250Hz , id need to include a "band pass crossover" also?

Am i interpeting this correctly, or at least in the same ballpark?