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Old 28th March 2006, 21:50   #31
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Quote:
Originally Posted by Autophile
There are no problems using a car bass driver in home B&T. There are lot of DIY people in the US using ID Drivers for Home subwoofers. One of them is Mr. Bruce Edgar of Edgar Horns (one of the exquisite horn loaded speaker brands)
I am also not a big fan of dudes who make home audio loudspeakers for a stereo setup with a seperate subwoofer.

Anyway, how can one explain that a car sub will do equally well in a home and a car, as long as your room isn't the size of your average car passenger cabin, or trunk.

So typically a SQ driver is designed keeping in mind that the response has to remain flat after accomodating for the fact that in the in-car response of the subwoofer driver, the 'tail' of the curve lifts up when it operates in a small-volume environment i.e. the car. So, at the frequency corresponding to the largest dimension of the cabin (or trunk, as the case may be), there is going to be a 6db boost at that and lower freqencies, also referred to as cabin or acoustical gain. So when faced with the scenario of the room, the frequency at which this is going to occur is way above the band in which the driver plays. The subwoofer is expecting some assist from the room at the lower frequencies and there isn't any. So the driver is playing the lower frequencies at a lower spl than in a car. The sub in the picture doesnt appear ported either. And the sub is too much up against the rear wall, so I doubt there's a rear firing one. So without any equalization for correcting the response, the sub isn't going to be the same great sub that the IDQ is when it is in the car. And good subs shouldnt be equalized. I can't see where I must be going wrong, but I have never come across some LF driver doing it right in both circumstances.
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Old 29th March 2006, 11:53   #32
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Bruce Edgar horns Hardly need much help. I have heard his stuff since the 80s. see the Speaker Builder publications from 1980-86 and his stuff is all over that magazine.

The ID sub really bring up the last octave. At these frequencies the sub get no help from the car (the car's cabin size translates to a hum around 50-80Hz). Bruce normally uses stereo subs.

vivek, listen to the Sumokoo.
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Old 29th March 2006, 13:19   #33
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I will ask Palesha if his subs are available in Bangalore. By the way, I think he has some Dynaquest sub drivers.
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Old 29th March 2006, 14:51   #34
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Quote:
Originally Posted by navin
Bruce Edgar horns Hardly need much help. I have heard his stuff since the 80s. see the Speaker Builder publications from 1980-86 and his stuff is all over that magazine.

The ID sub really bring up the last octave. At these frequencies the sub get no help from the car (the car's cabin size translates to a hum around 50-80Hz). Bruce normally uses stereo subs.

vivek, listen to the Sumokoo.
Navin at 50-80 Hz there is music...and you can very well listen to that depending upon the quality of subwoofer. And it is not really a hum.

ID Subs have linear response curve in sealed boxes no peaks and dips at any frequency till 80-100Hz
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Old 29th March 2006, 16:04   #35
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Quote:
Originally Posted by Autophile
Navin at 50-80 Hz there is music...and you can very well listen to that depending upon the quality of subwoofer. And it is not really a hum.

ID Subs have linear response curve in sealed boxes no peaks and dips at any frequency till 80-100Hz
Sorry I meant hump not hum. I was talking about the midbass hump most sedans have. Again sorry for the typo.
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Old 29th March 2006, 17:36   #36
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Vivek, for 10000/- i think you should MAKE a subwoofer for your home. Most branded "imported" subwoofers will have a terrible one at that price.

Last edited by Sam Kapasi : 29th March 2006 at 17:38.
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Old 29th March 2006, 21:48   #37
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Well Sma he needs a good driver with say Fs in the mid 20s, Qts about 0.3-0.4 and Vas about 60 liters and a Xmax of 9mm linear one way etc... the drivers I know are not available locally. A good sub will run about 5K then a 150W plate amp will run about 4-5K and the box will cost atleast 3K. ofcouse this sub will outperform most 10-15K subs but the budget is a bit small.

Peerless India makes a copy of the Peerless 831727 (circa 1990) that Cream used to use in his 10" sub but I am not sure if it is available anymore. Sam can you wake Cream up. My mobile address book died when I flashed the ROM.
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Old 30th March 2006, 10:49   #38
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Got your point, Sam!

Now listen to this. One of our Bangy DIY boys (Ajayan Nair aka Ajju on diyaudio.com, Navin knows him) has made a subwoofer for a restaurant using the JBL 1202 car sub. He says it turned out to be pretty good. He asked me to come and see it. JBL car subs, I believe, have Qts figures close to that of home subs. He also suggested I check out figures of the 1204.

Angshu Das (Navin, you remember him?) said Peerless India sub drivers are available with Dev Electronics in Mumbai. He said he would try to find the phone number for me.


The reason I do not want to try too many things with the Boltons is that it may not be worth the effort. If I have a good quality driver, then I could start designing around it.

It will be nice if Cream can spare sub drivers, if he has them.

Last edited by Vivekphadnis : 30th March 2006 at 10:52.
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Old 31st March 2006, 10:41   #39
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Vivek, Cream lives in Mumbai even if he spare a sub or get you a driver how do we get it across safely.

beyond the basic T/S specs I would also like to know Bl amd Cms. If the JBL subs work there is nothing like it. I know Ajju and Angshu. Small world. Just ask Sam.
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Old 31st March 2006, 14:23   #40
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Getting it to Bangalore safely from Mumbai would indeed be a problem.

Sam, is it possible to let us have the T/S parameters of the JBL 1202 and 1204 and maybe any other 10 or 12 inch sub driver.

I was wondering if say two Bolton 12 or 15 inch drivers will not work with a high wattage amp. You know sheer size and power.
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Old 31st March 2006, 15:55   #41
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do you have any accurate specs on the Boltons.
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Old 31st March 2006, 17:45   #42
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I have measured the parameters for my bolton 8 inchers but i am not sure if they are correct. I could try the same method if I get new drivers.
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Old 1st April 2006, 10:18   #43
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Are you using the Mass Method. I find that quick and reasonably accurate. do youhave LMS or something?
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Old 1st April 2006, 13:23   #44
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Quote:
Originally Posted by Vivekphadnis
Sam, is it possible to let us have the T/S parameters of the JBL 1202 and 1204 and maybe any other 10 or 12 inch sub driver.
Actually i recently posted this - in a recent thread. I remember it was a picture and Navin rebuked me for that horizontal scrolling bit. I am sure you will find it.
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Old 1st April 2006, 13:44   #45
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I use speaker workshop. I have not measured the Vas of the 8 inch boltons. Is there a good page which explains how to do it in a simple manner?

Sam, I will do a search.
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