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Old 20th September 2005, 18:11   #1726
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Does it mean that all 4 channels can be run frequencies above 80Hz ? And that we can leave the LPF redundant if we are not adding a sub?

So, tell me if I understand this right - There is a Filter for each channel in a 4 channel amp with HPF and LPF - This same filter can be set to LOw pass/ Highpass for all/any channels depending on the speaker?

Hope I'm clear enough........
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Old 20th September 2005, 18:24   #1727
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Quote:
Originally Posted by aseem
In this case you would use the HPF filter for both the front and the rear channels. As the rear co-axials are not optimized for low frequencies. By setting LPF on the rear speakers, you can distort the tweeters on the rear speakers!
Rear co-axials are optimized like the front speakers to operate above 80 hz frequencies. LPF is used only for subs!
If you use an HPF for all channels, with no subwoofer, that means all frequencies below the point of setting (in this case 80hz) are lost. This is not a good idea. I find that running 6X9's on full range will give you a good amount of bass. Maybe the front channel can be cut off at 65/70hz.

By setting LPF on the rear channel you will not distort the tweeter. That is incorrect. There is a passive crossover built on the rear coaxials. This passive crossover (a capacitor) does not allow low frequencies to pass to the tweeter. When you set a co-axial speaker to LPF, the tweeter simply wont work!

Quote:
Originally Posted by SoundManiac
Does it mean that all 4 channels can be run frequencies above 80Hz ? And that we can leave the LPF redundant if we are not adding a sub?

So, tell me if I understand this right - There is a Filter for each channel in a 4 channel amp with HPF and LPF - This same filter can be set to LOw pass/ Highpass for all/any channels depending on the speaker?

Hope I'm clear enough........
If you are using 4 speakers and no sub with an amp...

I find the best results (simplest results) can be had by keeping the filter "off" for the rear and the HPF "on" for the front and HPF frquency at 60-70Hz.

To elaborate on your question, most good amplifiers have a switch that allows you to choose low pass, high pass or off on each PAIR of channels.

However certain economy amplifier will provide just a LPF in the rear (assuming that you will either run a full range rear speaker, or a subwoofer)
and an HPF in the front (assuming that you will run either a full range speaker or a mid-high speaker in the front)
This is mostly done to cut costs.

I hope this clears everything for you
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Old 20th September 2005, 18:31   #1728
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Quote:
hope this clears everything for you
You bet it does!!!

Just another supplementary....

Quote:
However certain economy amplifier will provide just a LPF in the rear (assuming that you will either run a full range rear speaker, or a subwoofer)
and an HPF in the front (assuming that you will run either a full range speaker or a mid-high speaker in the front)
What about sony 504?

Can we switch off the filter for rear? And later on when we add a sub, set the filter to LPF?
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Old 20th September 2005, 18:34   #1729
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Quote:
Originally Posted by SoundManiac
What about sony 504?

Can we switch off the filter for rear? And later on when we add a sub, set the filter to LPF?
Currently I am assuming you use the rear channel of the 504 to drive your rear speakers. I recommend you keep the LPF/hpf off. Just keep it in Off mode.

Later on you may use this channel to only drive your subwoofer. In that case the LPF would be On.

When you do get the sub, do you plan to buy another amplifier, or do you plan to run 4 speakers and a sub off the 504?
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Old 20th September 2005, 18:47   #1730
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Quote:
Originally Posted by SoundManiac
Had some doubt wrt to the HPF and LPF usage of amps.

Say I have a 4 channel amp sony 504 with both HPF & LPF

Query is - How is the HIgh pass Filter used for front channels? (I am an aboslute novice and have no idea at all of how speakers are connected!!)

I imagine that the 2 channels going to the front speakers will have a HPF set so as to send High frequencies to them. Doubt is that if i use a compo system - Tweets will be fine with Higher frequencies but what about the mid bass speakers? What about their sound if only high frequencies are fed through the front channels?

Or is it that I'm missing something totally basic?

Whatever be the case, please enlighten me on the count.

P.S. Checked out Buffetfans system in the Baleno and it sounds really good! Thanks buffet for your help!!
I switched off the filters in my system as I wanted the speakers to provide Bass too...I may not take the sub with me on long drives and will then find it painful to reach behind the seats to tinker with the filter settings again...
so what you heard in my car was with the filters offf...

components will come with a crossover that acts as the filter to redirect the corect frequencies...so I guess no need to put HPF on in the front too...if there is no sub and you want the sound from Front...you may find it devoid of bass...and if you power the rear speakers for bass..the sound stage shifts a bit...

Last edited by Buffetfan : 20th September 2005 at 18:50.
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Old 20th September 2005, 18:51   #1731
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Quote:
Originally Posted by Sam Kapasi
Currently I am assuming you use the rear channel of the 504 to drive your rear speakers. I recommend you keep the LPF/hpf off. Just keep it in Off mode.

Later on you may use this channel to only drive your subwoofer. In that case the LPF would be On.

When you do get the sub, do you plan to buy another amplifier, or do you plan to run 4 speakers and a sub off the 504?

Thanks so much sam! That clears all my doubts.....

And no, I don't have my system installed yet! The queries were for right information. As for my setup, I'll be trying out my aiwa 3 way speakers 150Watts RMS 6 Ohms impedance (from my Old home audio setup) for the rear. Lets see if it works out.....and if they do work then how about the filter setting - there arose the query.
But now i figure it out - rear filter would be off!

Later on when i decide to go in for a sub, I would be buying another amp a sony 502 may be. I wont bridge my front compos and the rears speakers on the front channel (as I would loose fader effect)

Hey! but do i get it right why you ask this query? What about the filter setting if all 4 speakers(front compos and rear) run on 2 channels and the other two are bridged for the sub? Yeah but what then? Filter off on the front two channels and LPF for the sub?
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Old 20th September 2005, 18:58   #1732
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no there are 2 ways to do it then.
Either filter off on the front two channels and a passive crossover for the rear, or filter off on the rear, connect the woofer in tri mode and you can still have fader effect, but the woofers a little overworked and so's the amp.

Forget it, you're on the right track here
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Old 20th September 2005, 19:15   #1733
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Quote:
Originally Posted by Sam Kapasi

By setting LPF on the rear channel you will not distort the tweeter. That is incorrect. There is a passive crossover built on the rear coaxials. This passive crossover (a capacitor) does not allow low frequencies to pass to the tweeter. When you set a co-axial speaker to LPF, the tweeter simply wont work!
Sam I dont feel what I had mentioned was totally incorrect. I am aware of the crossover built in the coaxials, however I believe for tweeters a minimum of a 2nd order crossover should be use in order to prevent the tweeter from seeing any bass frequencies and to be safe, since they are most susceptible to damage. Am I totally off track?
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Old 21st September 2005, 10:15   #1734
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Quote:
Originally Posted by aseem
For the subwoofer I have consulted Gunbir and he suggested Hertz ES 300 D for the sub. This sub has 350 watts RMS, has a paper cone (as opposed to Aluminium), has dual voice coil (I am planning to connect this in parallel to run the amp in 2 ohms). I have read that paper cone is superior to Aluminium cone as its less prone to scratches and has a warmer sound. Experts is this a good setup?
Secondaly coming to the box design... after a brief research there are basically three designs that are common:
1) Boxed
2) Ported
3) Bandpass
...Boxed sub would make most sense. Since I have never experienced this before, experts please chip in with what you feel will most suffice my requirements!
1. Which Aluminum sub are you comparing teh Hertiz woofer to?
2. I assume ther Hertz is doped paper. Aluminum drivers (subs, midranges, tweeters) in general can expereince breakup at higher frequencies and I too usually prefer doped paper to many other matierials (incl polyproplene, metals, kevlar, carbon fiber etc..) that is not to say that other drivers are bad it is just a preference.
3. I would suggest that you choose between bass-reflex (also called ported) and sealed. Bandpass bass often gives one noe bass and while is can be very efficient the quality of bass is not as good as bass-reflex or sealed. sealed bass is great but is least efficient (need more power and bigger wofoers for same SPL). If you are buildig a box you could build a sealed box and if you find the bass level not adequate convert it into a bass reflex box (taking into consideration that sealed boxes are usually smaller than bass reflex boxes).

that said do you ahve the T/S specs of the driver. The primary specs to note are Fs, Qts, and Vas. Other specs would be BL, Cms, Mms, Mes, MMs, Xmax (linear one-way), and Sens/Eff. Some drivers work better in sealed boxes and other are designed for bass reflex boxes.

Lastly if you areally want bass that will have the definition of sealed bass and some of the efficieny of bass-reflex you could consider transmission line but these boxes are huge and you can kiss your trunk good bye.
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Old 21st September 2005, 10:17   #1735
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Quote:
Originally Posted by aseem
The reason I chose this amp however was the fact that it has 200W RMS in bridged mode as opposed to the Sony 504 and JBL 50.4 which have around 120W RMS. !
120W and 200W is less than 3db difference....see
http://www.team-bhp.com/forum/showth...?t=7500&page=4 (want to buy a good car audio system)
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Old 21st September 2005, 10:26   #1736
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Quote:
Originally Posted by aseem
Sam I dont feel what I had mentioned was totally incorrect. I am aware of the crossover built in the coaxials, however I believe for tweeters a minimum of a 2nd order crossover should be use in order to prevent the tweeter from seeing any bass frequencies and to be safe, since they are most susceptible to damage. Am I totally off track?
most coax drivers have a 6db/octave filter (single cap) at 8kHz or above. the 6db filter is simple and small and cheap and btw also has excellent transient response and low phase shift.

now if your amp has a LPF filter at say 1K only freq. below 1K are being sent to the tweeter. By 1k the tweeter filter (at 6db/octave) has attenuated freq coming to the tweeter by 18db (6db at 4k, 12db at 2k, 18db at 1k) maybe a bit more. since this is normal for the tweeter the tweeter will produce little if any sound.
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Old 21st September 2005, 12:00   #1737
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What about the filter setting if all 4 speakers(front compos and rear) run on 2 channels and the other two are bridged for the sub? Yeah but what then? Filter off on the front two channels and LPF for the sub?
You will not have fader control then (shifting power between front and rear)...

Many HUs come with filtering option...the 9750 I had i my car has an option to put a HPF filter to the speakers...but it happens with all 4 simultaneously and is useful if you have a separate Sub (it also has a separate volume/level (12 levels) control for the sub on the HU). There is another settign where you can use the rear for Bass and the front for the rest

Last edited by Buffetfan : 21st September 2005 at 12:01.
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Old 21st September 2005, 12:38   #1738
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9750 have two modes

NW : High - Mid - Low (active)

Its front stage active with subwoofer at the back, You dun need passive crossovers, you need 5 Channel amplifier, two channel running tweeters, two channel running midbasses and one channel on subwoofer. Make sure you need to have right crossover points on head unit. And amplifier gains matched. No fader works in this case.

STD : Front - Rear - Subwoofer

You have to use passive network. and you need same 5 channel of amplification. two powering front...two rears and one sub...fader works in this case.
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Old 21st September 2005, 13:01   #1739
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or you could run the front and rear outputs (std mode) into an active XO and have an active system with fader.

http://www.crutchfield.com/S-is4Y474...?g=82600&avf=N

Last edited by navin : 21st September 2005 at 13:07.
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Old 21st September 2005, 13:55   #1740
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Hello boys, I am back. My dad was not keeping well and I had to take a break.
I had not thought of this at all. Maybe I can use the HPF for the JBL 426s and let the 936s go full range. Will that have any advantage?
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