midbass imaging?

[keep_hope_alive Premium Member]

I hear ya dude. Foam weatherstripping is my budget trick. I keep a box with a variety of widths and thicknesses on hand for installs.

 

[VWBobby 10+ year member]

In the systems I've installed, I've always taken a little time to mount the speaker on-axis to the driver's ear. Sit in the vehicle and visualize what angle the speaker must be to be pointed straight at your ear or near the headrest. Use dowels or hold the speaker by hand (or a helper) and measure the offset on the large side. This will give you the thickness needed for the correct angle. I mount all speakers on axis and keep the tweeters and mid-ranges up high in the door.

Keeping the speakers on axis to the listener also has the advantage of not beaming or canceling out each other firing across the cabin head on. //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif Almost no time alignment is needed also.

 

[keep_hope_alive Premium Member]

Agreed! But aiming is advanced and requires permanent modifications and 20 hours or so, totally worth it though.

I keep my mids and tweets on-axis, midbass is still off axis but I will soon experiment with larger kicks and door pods.

 

[VWBobby 10+ year member]

Exactly. I just thought of something I wasn't exactly correct about..... //content.invisioncic.com/y282845/emoticons/wow.gif.23d729408e9177caa2a0ed6a2ba6588e.gif Some speakers actually work better off-axis because of the beaming effect. I was actually backwards in my post above. I read somewhere recently where they actually measured the sound through a narrow port at various angles and found some speakers beam a lot more head on or around 20 degrees compared to 45 or 60, lets say... //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

Pods are good for speakers that like sealed enclosures, makes a big difference. I've used some poly coned speakers that work well in pods on-axis. Right now I'm running some Aura 8's in door panels at rib cage height. They are on-axis to my ears and sound great, LPF'd at 500hz using a passive xover. I just cut some MDF rings and fiberglassed them in after hot-gluing dowels to hold the rings at the correct angle.

Honestly, I have about 5 hours into the whole project.

 

[Chaotic_Thought 10+ year member]

On a positive side note, my 1/0 came in this morning.

 

[trumpet 5,000+ posts]

I don't know what CDT mids you have but in my experience the CL-6 mids are very light on midbass impact. It helps immensely to reinforce those frequencies with a good subwoofer that can sound good playing bass guitar, kick drums, and so on.

Please don't build a sealed enclosure for your mids. While someone might get lucky and get good results, this is a bad idea. Use the door as the enclosure. I have a write-up on my site for how to do this or you can look up basically any experienced installer's build thread(keep_hope_alive, for example) to see ideas to accomplish this.

Two years is a long time to suffer a disappointing sound system. For less than $100 in materials you could treat both doors and get much better midbass without upgrading the speakers.

 

[keep_hope_alive Premium Member]

i agree that sealed door pods should only be done with speakers designed for such an install - i.e. raw drivers, not standard car audio components. my sealed pods will be for some Silver Flute 6.5's and i'll also experiment with Dayton Reference woofers. i'll measure the actual T/S and model the enclosures for adequate volume. I may also incorporate an aperiodic vent to the door cavity. i'd like to have a removable speaker baffle so i can try a variety of speakers without changing the actual pod. i did this in my kicks and it was very handy.

 

[Why So Cereal? 5,000+ posts]

i agree that sealed door pods should only be done with speakers designed for such an install - i.e. raw drivers, not standard car audio components. my sealed pods will be for some Silver Flute 6.5's and i'll also experiment with Dayton Reference woofers. i'll measure the actual T/S and model the enclosures for adequate volume. I may also incorporate an aperiodic vent to the door cavity. i'd like to have a removable speaker baffle so i can try a variety of speakers without changing the actual pod. i did this in my kicks and it was very handy.

make sure to post up some results. i'm looking into both of those exact mids, and they will probably be in pods

 

[VWBobby 10+ year member]

I'm tuned in for any results you have.//content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif A removable or block-able vent would be great to have for testing various drivers and still be able to adjust the 'enclosure'.

 

[keep_hope_alive Premium Member]

it will happen soon - i'm getting fed up of having brand new drivers sitting in boxes and not in my car. //content.invisioncic.com/y282845/emoticons/furious.gif.fc81ca146dbff91fede3ed290dbc4f4c.gif

but i plan on incorporating these in stages. i think the kicks will be done first - to accommodate anything 7" and smaller. then i'll run a kick midbass while i experiment more with full range 2" drivers at the apillar and dash. then i'll build the pods by taking the lower half of my door panel and making a decently large enclosure (considering) and I agree the door aperiodic vent should be removable. i typically use two speaker grills to sandwich fiberglass between - a wood circle could be fitted instead.

of course, i'll take more pictures than necessary and RTA everything. //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

 

[VWBobby 10+ year member]

Sounds like a fun project. //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif Just so you don't have to re-invent the wheel.....I'll tell you what BMW did to install the speaker systems in the Harmon-Kardon setups. 6.5" speaker down in the door near kick panel, 3" full range in door about 8" above driver/passenger lap area firing straight across the cabin. A set of tweeters up in the a-pillars. 6 more speakers for rear fill. Personally, I don't think the sound could be improved much - unless I replaced all the drivers with ones that have a natural roll-off that blends with the next speaker in the chain. It really does sound that good.//content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

 

[keep_hope_alive Premium Member]

I have considered upper door mids in lieu of kick mids. I haven't heard one of those setups do two seats well. My goal is 2 seats with symmetric or minimal T/A

 

[its_bacon12 10+ year member]

I have some unknown model CDT comps in the doors of my 03 F150 ext cab. When sitting in a normal driving position, the midbass response is rather lackluster. However if i move my head more towards where the head unit sits in the dash, the midbass response improves dramatically. Now i know i am moving more on axis to the drivers, and that the doors are not deadened, but what can be done to move the midbass focus higher in the cab?

Cars are an absolute nightmare when it comes to audio. Chances are you either are experiencing cancellation due to reflections or specific nodes in your car. The frequencies you hear when you move your head, but don't hear otherwise, are likely positive interference. Midbass seems about the right frequencies for that to happen, similar how bass experiences this in home environments.

 

[hispls 5,000+ posts]

Lots of good suggestions here IMO. I would be shocked if you experimented with ALL of them and still weren't happy.

Also I don't think the equipment is the problem and throwing different mids in there would likely do little or nothing to solve what is clearly an accoustic problem with the vehicle and speaker locations.

 

[zako 10+ year member]

I have some unknown model CDT comps in the doors of my 03 F150 ext cab. When sitting in a normal driving position, the midbass response is rather lackluster. However if i move my head more towards where the head unit sits in the dash, the midbass response improves dramatically. Now i know i am moving more on axis to the drivers, and that the doors are not deadened, but what can be done to move the midbass focus higher in the cab?

What you're observing seems like a symptom of a car with no time correction for the front midbasses. When you move your head to the center of the vehicle, the distance from your ears to your speakers is the same for each speaker, and so the speakers are roughly in an acoustic phase. When you move your head away towards the normal driving position, the speakers are a little out of phase. Low frequencies are the ones that are most affected by the phase issues. If you don't like it, buy a stereo or a processor with time correction. Pioneer is coming up with a unit that automatically tunes TA and equalizer soon, this may be worth looking into.

Some people also mentioning aiming your midbasses. My guess is that aiming midbasses differently will not affect the frequency response in the low frequencies, but it can affect the frequency response towards the upper frequency limit of the driver. All drivers experience a phenomenon called beaming, which basically reduces the dispersion of sound at the upper end of driver's limit. For 6.5 inch drivers this should start somewhere above of 2-3KHz, well above the midbass range.

Of course, all of this could be wrong and you are experiencing the work of some other sonic gremlins..