Alpine Bass Focus

billz428

I have the Alpine HU 9813.
It has a feature for Bass focus.
I have the time delay already set,

Does the Bass Focus affect the time delay?

I did not really understand Alpine instruction.

Any help would be great.

billz428

Yea , I agree but it does not make sense?

It also states in the manual Bass focus settings will alter time delay.

Thanx

billz428

Thanx your explanation does help some.

My head hurts!
I,m going over my manual again.
Is any one out there using this feature?

billz428

These are my settings
Front L- 40in- 1.5 delay

Front R- 60in- 0.0

Rear L- 32in- 2.1

Rear R-56in- 0.3

Sub -32in- 2.1

How do I use these numbers to adjust my Bass Focus?

arun1963

Are those the actual, measured distances between you and the speakers?

billz428

From speaker to my head, this is in a 1998 GMC truck.
There is dual subs but they have a mono signal.
First numbers are in inches, second is the delay setting as from Alpines site.
I can`t figure out the Alpine instructions....

arun1963

Set the sub to 0. Set front left and rear left to 3.1ms. Set front right and rear right to 4.6ms. Try it and see if its better.

billz428

Thanx , I,ll report later .
How did you come to these numbers?
Simple please if your a math genius, as I,m challenged HAHAHAHAHA!

arun1963

You time align in m/s. 1 m/s of time = 13" (appx) in distance, @ speed of sound. Delay everything from the sub. Hence sub is at 0.

You want sound from the four speakers to arrive at your ears at the same time. Even though they are different distances. The settings I gave earlier may not make this happen. Although one of the alpine manuals I read gave that as an option. You can also try the setting below and see which works better.

F right = 60" = 60/13 = 4.6m/s
R right = 56" = 56/13 = 4.3 m/s
F left = 40" = 3.1 m/s
R left = 32" = 2.5 m/s

I think this may work better.

billz428

The earlier setting did not work,lol
I will try these .
Thanx for your time I do appreciate it!

billz428

There is TA and then seperate function and setting. there is Bass focus.
You adjust one and the other changes!
I just going to stick with time alignment and leave the Bass Focus alone.
The TA is easy to set from the web site,plug in distance , the settings are displayed.
I thought for sure some Alpine HU expert that competes could slam dunk this one HAHAHAHAHA!

arun1963

DSkip wrote: »

I never realized how difficult it could be. My pioneer lets you choose units in inches or cm, and lets you set the distance from the listener on each speaker (and each sub) separately. It seems like alpine made it much more difficult than it needed to be. I assume bass focus = TA. Why make it so technical and cause the listener to do computations when its unnecessary?

IMHO the TA feature on the Pio's is more accurate than Alpine. With pio you can set the TA in increments of 1/2". With the Alpines this is 0.1m/s which translates into 1-3/8". Measuring in inches or m/s are just two different ways of doing the same thing.

The 'measured' settings are just a starting point. Exact measured settings, rarely, if ever give you the 'best' sound. For one, the measured PLD between your mids, is normally greater than what sounds best. I.E. your TA would be set for less (reflections are one reason). With your sub to mids, the opposite seems true. Yes it is a bit complicated. Start at the measured distance then play around.

arun1963

billz428 wrote: »

There is TA and then seperate function and setting. there is Bass focus.
You adjust one and the other changes!
I just going to stick with time alignment and leave the Bass Focus alone.
The TA is easy to set from the web site,plug in distance , the settings are displayed.
I thought for sure some Alpine HU expert that competes could slam dunk this one HAHAHAHAHA!

Bass focus on the Alpine seems like BBE on the pio units. It basically boosts the 50-150hz range. Just use TA and keep this disengaged. The second set of settings would be a starting point. You would have to tweak from there on.

Getting 4 speakers to sound like 2 and then getting these in phase, requires TA at two levels. At your hu+processor would be one option. It can get complicated and expensive. Much simpler to ditch the rears and only run fronts + the sub.

No 'Alpine hu expert who competes', can give you the 'slam dunk' numbers for your setup. Three raesons.

1. No sq champ would ever run rears.

2. I have already explained that 'measured' distances are only a starting point. The final slam dunk numbers would be based on the internal accoustics of your cabin as well as your install. You have to tweak and tune your way there.

3. Even if he can, he's not obliged to.

A bit of respect to those WAY ahead of you goes a long way. You'd learn much faster. Mocking them just makes you look silly.

billz428

Thanx for your time Arun, no mocking ment or intended, humor maybe.
Agreed, I,m leaving the bass focus alone, more trouble than worth to me.
The Time delay setting feature is a real asset to this HU.
I will never run another with out it.
Thanks everyone.