Car Audio Advice from the Audio Gurus: Use "Search thread" before posting a new Q!

[DerAlte]

Originally Posted by mohang_j

Navinji, I have gto506 components, can i make an active crossover with band pass between 100Hz to 5kHz for the woofer and high pass from 5kHz+ for tweeters, want to avoid woofer playing kHz+ music.
...

Doing "active crossover" is a non-trivial task, involving one amplifier for each driver - mid-bass and high (and mid, if one wants a 3-way active) . The frequency band that one wants to allow through each driver is set either at the HU (then the HU must have separate outputs for each f band) or at the amp (then the amp must support 'band-pass'). For 2-way components, you will need a 4-ch amp.

You have 2 courses of action:
1. Get the cross-over as a spare (maybe a pair) from JBL
2. Make a new pair of cross-overs - search for XO or Crossover related threads for the values to use (I think 5KHz in too high - should be preferably 4Khz) (you may get ready-made crossovers at SP Road, at Globe or such shops)

[mohang_j]

DerAlte,
Thanks for the immidiate repply

Originally Posted by DerAlte

Doing "active crossover" is a non-trivial task, involving one amplifier for each driver - mid-bass and high (and mid, if one wants a 3-way active)

I already have a subwoofer+amp and i can go for Sony or any other cheap Amp and i have seen people

You have 2 courses of action:
1. Get the cross-over as a spare (maybe a pair) from JBL

Its a discontinued product and even if available it will cost more.


2. Make a new pair of cross-overs - search for XO or Crossover related threads for the values to use (I think 5KHz in too high - should be preferably 4Khz)

will consider that

(you may get ready-made crossovers at SP Road, at Globe or such shops)

Instead i can make my own.

[redfire]

Originally Posted by DerAlte

(I assume the sub phase has already been set appropriately so that it is blending in with the mid-bass in front)
....
Then sit back and enjoy the music - forget about lows, mids and highs!

Many thanks DA for your valuable inputs. Going to car with laptop, fav CD and my tool kit . Will be baselining the levels as you recommended and will start from there. Do you think all the adjustments in he HU should be put to flat? I know and do the same with home audio (in fact the home audio components I use has no complicated things like this), but can we do some tweeks in car as the environment is totally different? What are Band-frequency-Q factor things? How to fiddle with them safely if needed? What about the LPF / HPF in HU and Loudness?

[Bass&Trouble]

Originally Posted by mohang_j

Navinji, I have gto506 components, can i make an active crossover with band pass between 100Hz to 5kHz for the woofer and high pass from 5kHz+ for tweeters, want to avoid woofer playing kHz+ music.
(brought components from Manson but he has misplaced one of the crossovers and the crossover just has one 3.3mfd capacitor and an inductor - don't know the value need to check.Now i have to make passive or active crossover my own.)

I havent explored the JBL crossover but is it a 1st order or 2nd order? You can check this by seeing the PCB tracks - is the inductor in series with the woofer's path?

Now if it indeed is, then it means that the tweeter section is first order. I do not recommend you lowering the crossover frequency for the tweeter. You could blow it with less than rated power. Unless you go one step further and design a 2nd order section for the tweeter.

You also cannot just lower the cut off of the woofer by using a different value inductor. You will have a hole in the response. Best POA would be point (1.) as under.

Originally Posted by DerAlte

You have 2 courses of action:
1. Get the cross-over as a spare (maybe a pair) from JBL
2. Make a new pair of cross-overs - search for XO or Crossover related threads for the values to use (I think 5KHz in too high - should be preferably 4Khz) (you may get ready-made crossovers at SP Road, at Globe or such shops)

[greenhorn]

if you change the inductor , all it needs is a corresponding change in the capacitor in the HPF right ?

I've actually toyed with the idea of using a 6" comp, changing the HPF and LPF values , and then adding a 4" in the dash as a mid range to compensate

[DerAlte]

Originally Posted by mohang_j

...Instead i can make my own.

Brilliant! All the best - we will be waiting to hear the results.

Since you are up to creating your own, perhaps a good starting point would be to reverse-engineer the lone remaining JBL XO. If you can trace out the circuit and values, @bass&trouble will be able to help you make the right one.

[mohang_j]

Originally Posted by DerAlte

Brilliant! All the best - we will be waiting to hear the results.

can somebody help me calculating number of turns & wire gauge for the inductor value.

[cooldude1988765]

Most of you will laugh at my query but i really need this clarified.
I have a wagon r and wanted to know if the sound stage would be improved if i get the rear 6 x 9 installed in a box under the front seats. As most of you know the wagon R has a very small front speaker provision and i cant spend too much on front components either.
I drive most of the time and no one ever sits at the back.

[greenhorn]

I dont think the soundstage will improve , but if you install it in the back, your low frequency response will improve

And i dont think you can put 6x9's in the front.

actually , front components of a series usually cost about the same as the 6x9's

[mohang_j]

Originally Posted by cooldude1988765

Most of you will laugh at my query but i really need this clarified.
I have a wagon r and wanted to know if the sound stage would be improved if i get the rear 6 x 9 installed in a box under the front seats. As most of you know the wagon R has a very small front speaker provision and i cant spend too much on front components either.
I drive most of the time and no one ever sits at the back.

If no one sits at back better go for 4 inch components, 6x9 under seat will give you only bass since mid and high frequencies are directional.

[cooldude1988765]

I already have the 6x9s installed at the back. looking more for the mids than the bass. I am already satisfied with the bass from my sub woofer in the boot.
The only reason why I am thinking of this is because i turn of my front speakers because they sound crappy and the sound (from the 6x9s) feels like it is playing from a distance.

[greenhorn]

maybe you could add an extra tweeter

[cooldude1988765]

Tweeter for mids ???

[DerAlte]

Originally Posted by mohang_j

can somebody help me calculating number of turns & wire gauge for the inductor value.

Desired inductance value (based on the circuit calculation) and Wire gauge (based on what you can get; should be able to take the desired steady state current) should be the starting point.

Then you can use an online coil designer like this one to find out the number of turns and layers.

[DerAlte]

Originally Posted by cooldude1988765

I already have the 6x9s installed at the back. looking more for the mids than the bass. I am already satisfied with the bass from my sub woofer in the boot. ...

What speakers do you have in front currently? I guess this is in the stock location on the upper surface of the dash near the A-pillars.

The sound-stage is basically because of the directionality (what our ears perceive) of mid and high frequencies. The stock location in the Wagon-R is not bad, but you need decent speakers there to get a good sound-stage.

Getting the ovals below the front seats would aggravate the problems, not solve it. Perhaps you could try changing the polarity of the ovals (in the current location) and see if it improves the situation for you.

Putting tweeters might be a simple incremental solution to improve the sound-stage. Ultimately you have to think of getting a decent set of components (4" from Illusion, Blaupunkt, JBL or such).