Amp for db401 and db691

Tron05

I plan to upgrade my car setup from current all pioneer

i will be retaining my old pioneer HU 3790

I am from India, the car is a Hyundai Santro.

The stock default location is a 4 inch in the dash -- i intend to put in a db401 here

The rear stock is a 5.25 inch..... i intend to put in a db691 on a MDF rear tray.

now i am really confused on how to power them through an amp.

db401 is a 45watt rms @ 4 ohms
db691 is a 100watt rms @ 4 ohms

what kind of amplifier should i look for to power these 4 speakers?
i.e how powerful(rms watt) amp do i need to get??

Also will a higher power amp be harmful for the front db401 ?

jacob.simpson

Bang on buddy, i gifted my nephew in India, Bangalore DB401 just a month ago, my goodness what a differenct it made to the Santro (White 1999 he still keeps it in a mint condition) run the 401 with you HU power more than enough, (To answer your question of over riding your 401 yes any speaker will distort or break if wrongly powered that is even with a underpowered amp if you over ride the amp it may feed distorted signal to the speaker and break them most of the times this is what breaks the tweeter and speakers in general than overpowering - stick within the range) get a good 4/3/2 Ch bridgable amp for the Sub and the Rear 691, you can bridge 2 ch for the sub and run the 691 using the other 2 channels, enjoy the POLK you made the best decision. Post a feedback how it sounds once you complete your set up.

MacLeod

Something in the 75x4 RMS range would be a good match for those speakers.

Tron05

@jacob.simpson: thats good to know about your experience with the db401.

i have not yet tried running it from my HU yet. But, wouldn't running it from the HU underpower it as the HU would provide only 22watts rms.

if only the rear db691 are run through the amp, will it not totally overpower the front?

Also i dont have/intend to get a sub(juz trying to save my bootspace)

@MacLeod: As jacob pointed out, wouldn't there be any distortion/burn outs if the front too are powered with the 75 X 4 watts amp?

jacob.simpson

In that case get an amp with not more than 50 rms each channel, since you may burn out the 401s but it will be bit compromise on the 691 because they will be little undepowered, thats fine as long as you are getting a good brand with a least distortion at peak levels.

MacLeod

Tron05 wrote: »

@MacLeod: As jacob pointed out, wouldn't there be any distortion/burn outs if the front too are powered with the 75 X 4 watts amp?

No so long as you dont push them too hard. Your car is capable of going 100 mph. Is it going 100 mph all the time? Nope. Same with an amp. Music is dynamic and so long as youre listening to it at MUSICAL levels and not cranked up to ear splitting levels, youll never use all the amps power. Besides, the speakers will usually tell you when theyre being overdriven. Just use common sense with the gain setting and volume control and youll be fine.

jacob.simpson

In that case get an amp with not more than 50 rms each channel, since you may burn out the 401s if you go in for higher wattage, but it will be bit compromise on the 691 because they will be little undepowered, thats fine as long as you are getting a good brand with a least distortion at peak levels.
All said thats more than for Santro or even a sedan, dont be fooled by those tiny monsters 401 you will find such difference in sound quality, you will start hearing instruments what you have not heard in the old albums what you have. Enjoy them.:)

Tron05

Call it stupidity or ignorance, here is my question!!

since the HU gives 22 x 4 rms,
Is it possible to bridge the HU outputs to the front speakers like say 44 x 2 rms??

and use the rear pre-amp out from the HU to a 50 x 4 rms amp to power the rear db691 in bridged mode say 100 x 2 rms

so now both speakers are powered to their max rms heheh

jacob.simpson

If you can do As Tron05 says, that will be one hell of a set up.:D

Tron05

^^but is it possible to bridge the HU channels??

Thom

It's not possible.

MacLeod

Its also not 22 watts per channel. More like 10 REAL WORLD watts. Head units are horrible power sources. Do the right thing - get an amp.

Tron05

can anybody tell me the difference between the db690 and db691?? specwise both look juz the same..

MacLeod

Im not 100% but I dont think there is a huge difference. I think Polk just tweaked the DB's a little to get a little better performance out of them. Still basically the same speaker just a little better sounding.

Tron05

Thnx guys for the help..

This is what i have got

Front 4" db401
Rear 6 x 9" db690
Amp: JBL GTO504 (4 channel 55 x 4 rms)
Wiring: Monster Amplifier wiring kit MC-8

The rears are powered from the amp and 2 channels are free...for a future sub maybe....wat wattage sub should i think of..if i decide to add 1?

The soundstage is purely at the rear... the fronts really cant be noticed unless..its faded heavily towards the front.

and the sound is gr8 from the 6 x9" ...cant say that about the db401 though...

cadenceclipse

thats cause their jealous and r screaming for those free channels. just keep the gain down... hook em up man!

MacLeod

Yeah definitely. Hook the front speakers up to the front channels, the rear speakers up to the rear channels and turn the rear gain down a little lower than the front gain. Youre wasting power and not getting the best out of your stuff.

cadenceclipse

actually that'd b the front gain lower...

MacLeod

No it would be the rear gain. You want the rear speakers to play at a lower level than the fronts. That way they work as rear fill. Having them play louder than the fronts would have them working as front stage - which is stupid because THEYRE IN THE BACK!

cadenceclipse

good theory however fronts don't need as much power, 6x9s r more power hungry. c 4 yourself, maybe at same levels will work also..more gain does not mean louder, front r most likely more sensitive, needing less power.. no?

MacLeod

No.

More gain DOES mean louder until clipping. It means that with the gain set lower on the rears, the fronts will be louder than the rears. The gain syncs the amps input with the HU's volume. By having the fronts gain set higher its the same as turning the volume up higher on the fronts than the rears. You PROPERLY set the front gain (set it to where it does not clip) then you set the rear gain below that point. So your gains are set to below clipping and the rears are at a lower level than the fronts and now youve got rear fill instead and an overwhelming rear stage.

And the 6x9's are actually MORE efficient than the 4's but only by 2 db which is small enough that it wont be noticed.

cadenceclipse

more gain only means louder depending on speakers being compared. in this case macs right, i was unaware of 6x9s being more efficient. gain syncs amp input w/ hu output not volume. so anyway set the fronts up then tweak the rears so there not overpowering fronts. in a setup like that u may want more than rear fill anyway from those 6x9s. second thought w/ 55wrms those fronts should do fairly well, id think preference may come into play here.

Tron05

hey guys.... the installer didnt put the fronts on the amp saying that it will blow the speaker...(front 4 inch db401 has 45watts rms and the amp outputs are 55 watts x 4 rms)... isn't that right?

jacob.simpson

I dont think so you should have probs with that connection cause each 401 is rated at a peak of 135. Still best way to do that is contact POLK customer care and they should be able to clarify. And if you are connecting them to the amp dont push them too hard.

Thom

Does the amp have an adjustable high pass crossover? If not, is there a fixed hp frequency?

Tron05

yes..the amp has adjustable cross over settings(LPF,Flat and HPF) and cross over frequency control (12Db/0 octave crossover, variable from 32hz to 320hz)

GSRBOB

You should amp the db401's and just cross em high enough, say around 100-120hz.