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Old 7th July 2010, 21:24   #16
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Now i need to power a minimum of 120W RMS so that my Midbass is around the 107 db mark. Am i right in my understanding now ?
no - you need between 64 and 128 but closer to the 64

to get to the approximate figure we need 128-64 and then divide that by three = 21 watts then you add that to the first 64 and get 85 watts

but it is a logarithmic function so i assume that navins method of calculation would be more accurate - whereas my method is a bit of a guideline (despite being a thumbsuck) but yes according to my method you need 85 watts and according to navins method you need 75 watts - so im going to call the extra in my method a little "headroom" but you dont need as much as you imagine

again this is before other things like distance etc come into effect - remember all these calculations are at one meter - so as you go above one meter you need to increase the power accordingly ..... while if its closer than one metre you need to decrease the power accordingly

Deralte-ji - agreed with most of what you say - he made the mistake of thinking that the sensitivity adjusts but its a constant - whereas its output that adjusts according to power .... and i was getting confused by your wording but yes you do have a point upon your explanation

Last edited by naughty001 : 7th July 2010 at 21:28.
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Old 8th July 2010, 11:03   #17
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according to my method you need 85 watts and according to navins method you need 75 watts
10 log (85/75) = 0.54 db. Trust me you wont hear a 1db increase is loudness leave alone 0.54db.
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Old 8th July 2010, 12:24   #18
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10 log (85/75) = 0.54 db. Trust me you wont hear a 1db increase is loudness leave alone 0.54db.
i reckon that 1 db is about what you would just about percieve as a change in level if you have 20/20 hearing so i would suggest that this then depends on how good your hearing is

either way the differences land up being academic and i wont split hairs but i will state that i would probably prefer the midrange to be a bit louder than the treble ie even with the treble being slightly sparkly (note not harsh or sibilant) i still love clean and clear midrange .... so i would want the mid to get more power than the tweeter anyway and i wouldnt mind if the sound is noticeably skewed toward that clean clear midrange

thats merely a personal preference but i would fine tune that after more or less matching levels - and then tweaking from that after listening a bit - but then again i did run a pair of tweeters off a claimed 200 watts RMS per channel amplifier even though i was dropping levels by a huge amount but it survived and it managed to sound brilliant (not literally) while doing so

i dont know why but when it comes power from an amplifier i like to err on the side of excess and overkill .... but then again that way because even for SQ i love to have effortless volume levels and power when required and maybe this stems from having grown up around lots of live music i like to have that level thats around as loud as the live performance whenever its possible
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Old 8th July 2010, 19:09   #19
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Thanks a lot Guru's i did learn quite a bit over your thoughts.

I would want your comment on the following specs:

This is the Spec of an Amp that has differential crossovers.

High-pass filter crossover frequency (Hz): 40-450
High-pass filter edge steepness (dB/Octave): 12
Low-pass filter crossover frequency (Hz): 65-4500
Low-pass filter edge steepness (dB/Octave): 12

This is for the Midbass:
Let me know If i can bandpass in the Amp itself (Without using the Active XO of HU - i mean i ll just HPF at 80 HZ from the HU)

Can i use this Amp to bandpass between 80 Hz to 3K Hz?

Last edited by Mi10 : 8th July 2010 at 19:24.
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Old 9th July 2010, 09:26   #20
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Originally Posted by Mi10 View Post
Thanks a lot Guru's i did learn quite a bit over your thoughts.

I would want your comment on the following specs:

This is the Spec of an Amp that has differential crossovers.

High-pass filter crossover frequency (Hz): 40-450
High-pass filter edge steepness (dB/Octave): 12
Low-pass filter crossover frequency (Hz): 65-4500
Low-pass filter edge steepness (dB/Octave): 12

This is for the Midbass:
Let me know If i can bandpass in the Amp itself (Without using the Active XO of HU - i mean i ll just HPF at 80 HZ from the HU)

Can i use this Amp to bandpass between 80 Hz to 3K Hz?
does the amp allow you to use the hi pass section and low pass section simultaneously?

if not then yes you can hi pass at the headunit at 80hz and then low pass at the amp at 3khz to give you the bandpass between 80hz and 3khz

but if i was you i would look at the headunit you are purchasing and see if the headunits crossover doesnt allow for a bandpass - i rather suspect it might

as an example my alpine 9887 allows me to do that type bandpass for the mid pre-outs and then a high pass for the tweeter pre-outs - but my 9887 is restricted in that the adjustments are not infinite and are at specified points but im sure i would be able to do a 80hz to 3khz bandpass on my mid pre-outs ..... in this instance you could actually bypass the crossover on the amplifier and then to top it all off the alpines crossover allows me a choice of slope between 6/12/18/24 db/octave and i can also apply T/A to these channels individually if i like . Sorry if it seems like im showing off but many people dont like the alpine BUT those are the ones who havent really examined its capabilities

it is likely though that there are many kenwoods and clarions and pioneers and even possibly many more brands that could do similar so im not writing those off either (before anyone jumps on me for favoring the alpine) - its just that i can describe what the alpine does cos i have one
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Old 9th July 2010, 11:16   #21
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Originally Posted by Mi10 View Post
Can i use this Amp to bandpass between 80 Hz to 3K Hz?
Amps tht allow this have a HP/LP/BP switch.
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Old 9th July 2010, 13:34   #22
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Originally Posted by naughty001 View Post
does the amp allow you to use the hi pass section and low pass section simultaneously?

if not then yes you can hi pass at the headunit at 80hz and then low pass at the amp at 3khz to give you the bandpass between 80hz and 3khz

but if i was you i would look at the headunit you are purchasing and see if the headunits crossover doesnt allow for a bandpass - i rather suspect it might
True Nitin. Was just Contemplating between a High end HU (and mediocre Amps) and High end Amp (and mediocre HU)

Navinji would certainly prefer Best of both options . But i am a normal citizen (who has crazy ambitions..lol) belonging to the salaried class. So Vitamin M does matter to me

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Amps tht allow this have a HP/LP/BP switch.
I think the JL 450/4 V2 has it sir. Problem is it weights 19 pounds and my friend will have to leave half his belongings in the Airport, if he is geting me this
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Old 9th July 2010, 13:37   #23
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I think the JL 450/4 V2 has it sir. Problem is it weights 19 pounds and my friend will have to leave half his belongings in the Airport, if he is geting me this
There are medium-budget amplifiers available in India which have band-pass filters.
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Old 9th July 2010, 14:17   #24
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Agreed! JBL 1004/ Kenwood 8405 are 2 VFM options.
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