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View Full Version : 2 ohm of 4 ohm for components preference



OlogyAudio
07-24-2007, 03:36 AM
Would you rather have a 2 ohm or 4 ohm component set, everything else equal?
http://i8.photobucket.com/albums/a44/OlogyAudio/FG6p5IMGP3904.jpg
http://i8.photobucket.com/albums/a44/OlogyAudio/FG6p5tsfr.jpg

Right now I'm working on 2 and 4 ohm versions of that unit with less mounting depth and I'm liking the 2 ohm version better myself but I can tailor the 4 ohm to perform similarly... :yumyum:

Just a few cosmetics and minor changes to go on the 8 ohm so I'm finishing up the car audio motor designs now ;)

I'm looking at these t/s and drooling a bit:
Qes: .75
Qms: 3.12
Qts: .604
Fs: 49hz
mms: 13.7g
cms: .77mm/N
Re: 1.82 ohms
BL: ~3.2 Tm
Le: 0.1mH
Sd 128 cm^2
Xmax 7mm
RMS Pe: ~125W


The home audio version in the picture has 12 mm of xmax and RMS Pe of 200W.

PS. Matt is out of the picture and the other projects are moving forward although slowly so I’d rather not get off topic here… If you have other questions just send me a pm.

genxx
07-24-2007, 07:04 AM
I voted don't care. I can make either work if need be. Even an 8ohm. That is a luxuary though just because I have 10 amps to choose between. Benefits to both 2 and 4ohm.

Babs
07-24-2007, 09:06 AM
Beautiful driver!!

Yeah that mounting depth would be my constraint for sure.. Anything deeper than 3" is a questionable challenge for my install. I don't know if that's usual for door installs though, but I'd imagine my case is a bit tighter than average cars. 07 Subie.

teamquakecelica
07-24-2007, 06:05 PM
WOW... can I get some demo's?

Ryan

Spooby
07-24-2007, 06:07 PM
If its the same driver but with a difference VC then I don't care. It just comes down to what amplifier I have in front of me at the time of install.

OlogyAudio
07-25-2007, 12:19 AM
If its the same driver but with a difference VC then I don't care. It just comes down to what amplifier I have in front of me at the time of install.

The 2 ohm design I have is a little more sensitive.
The 4 ohm design I have is about 1dB/w less sensitive but has about 10hz more extension IB and a little more of a peak when in a small sealed kick.
Thereís a 2nd higher sensitivity 4 ohm design thatís suited very well for home audio :-D but thatís of less use with the 8 ohm higher excursion version available.

I could get the identical t/s with edge wound coils but that costs more ;) so thereís no reason for that...

Flipx99
07-25-2007, 12:24 AM
Anything over 2.5 is too deep for me.

Best of luck and glad to see you are still around.

OlogyAudio
07-25-2007, 03:09 AM
Anything over 2.5 is too deep for me.

Best of luck and glad to see you are still around.

What about if a .75" spacer is provided if it was 3" to start with?
Any input on the screw holes?

Thanks :) I'm still around it's just been a bit hectic and Matt is out of the picture.

Spooby
07-25-2007, 05:17 AM
Are those screw holes reinforced? If so I think its pretty cool, and a bit useless at the same time. It still doesn't prevent the occasional "opps I just poked a hole through the cone" accidents.

Also the T/S differences aren't different enough for me to change my decision on the poll. Just my 2cents though.

OlogyAudio
07-25-2007, 11:48 AM
Are those screw holes reinforced? If so I think its pretty cool, and a bit useless at the same time. It still doesn't prevent the occasional "opps I just poked a hole through the cone" accidents.

Also the T/S differences aren't different enough for me to change my decision on the poll. Just my 2cents though.

That is simply how the basket came from factory, however I'm thinking of countersinking the screw holes a bit more just for cosmetics... It won't matter much in car audio I guess but for home audio it will have an impact.

I was thinking along the lines of having the multi- vehicle screw hole drill configuration for the car audio version but I'm not sure if that will work out on this flange :crap: so that won't do...

Any input into a mesh grill? No Grill, Mesh grill built in to the driver, separate grill?

MiniVanMan
07-25-2007, 11:50 PM
On the low end I'd rather have the extension than the sensitivity. Especially in an infinite baffle type situation where excursion is going to come into play very quickly.

I'm guessing the specs you listed are for the 2 ohm version. If that's the case, it looks like the driver will run out of Xmax at around 80 hz. Very respectable in a door (I modeled at 89 liters for a leaky, closed box). So, even though you're getting more power to the driver due to the 2 ohm load, you'll still be hampered by the driver running out of excursion. For me that's a recipe for disaster in the power crazed car audio world.

So, I'd rather have the extra 10 hz on the bottom end, and give up the 1 db of sensitivity. 10 hz at that point is a 1/4 of an octave, and pretty considerable.

Either way it looks like they'll be nice drivers.

OlogyAudio
07-26-2007, 12:34 AM
On the low end I'd rather have the extension than the sensitivity. Especially in an infinite baffle type situation where excursion is going to come into play very quickly.

I'm guessing the specs you listed are for the 2 ohm version. If that's the case, it looks like the driver will run out of Xmax at around 80 hz. Very respectable in a door (I modeled at 89 liters for a leaky, closed box). So, even though you're getting more power to the driver due to the 2 ohm load, you'll still be hampered by the driver running out of excursion. For me that's a recipe for disaster in the power crazed car audio world.

So, I'd rather have the extra 10 hz on the bottom end, and give up the 1 db of sensitivity. 10 hz at that point is a 1/4 of an octave, and pretty considerable.

Either way it looks like they'll be nice drivers.

Oops. I was a little unclear. By 10hz lower I meant a 10hz lower f3 IB, anechoic. The xmax is going to be 7mm for both the 2 ohm and 4 ohm units simply due to depth restrictions.
The 4 ohm is excursion limited under about 95hz
the 2 ohm is excursion limited under about 97hz
Both units on the other hand will operate within their linear bounds so long as there is a LR4 highpass at 63hz in place at full rated power and there is no serious abuse. There is a little extra room to keep it from bottoming too easily though.
Power handling drops to about 70 watts with a LR4 @50hz.

In .3 cuft sealed no highpass is required with 70 watts
in .15 cuft sealed no highpass is required at full rated power.

Qts: .729
Vas: 17.9l
Fs: 49.5hz
Re: 3.02 ohms
Le: ~.07-.1mH
Qms: 3.12
Qes: .95
Sd: 128
Subject to change, and it will a bit on account of the Re...

MiniVanMan
07-26-2007, 02:50 AM
Oops. I was a little unclear. By 10hz lower I meant a 10hz lower f3 IB, anechoic. The xmax is going to be 7mm for both the 2 ohm and 4 ohm units simply due to depth restrictions.
The 4 ohm is excursion limited under about 95hz
the 2 ohm is excursion limited under about 97hz
Both units on the other hand will operate within their linear bounds so long as there is a LR4 highpass at 63hz in place at full rated power and there is no serious abuse. There is a little extra room to keep it from bottoming too easily though.
Power handling drops to about 70 watts with a LR4 @50hz.

In .3 cuft sealed no highpass is required with 70 watts
in .15 cuft sealed no highpass is required at full rated power.

Qts: .729
Vas: 17.9l
Fs: 49.5hz
Re: 3.02 ohms
Le: ~.07-.1mH
Qms: 3.12
Qes: .95
Sd: 128
Subject to change, and it will a bit on account of the Re...

It looks like the 2 ohm version could very well be a winner. Especially in car audio. I'm not normally a fan of 2 ohm drivers, as people are not usually aware of the real differences between them, and the sacrifices a lower impedance driver has to make. However, it seems you're approaching it pretty well.

I think a driver like this, if it performs, will do very well, if cost can be kept down.

What kind of coil are you using? That magnet is huge. Is Xmax being limited by the cone, or the coil? What's difference with the 8 ohm version, and what is keeping the 2 ohm or 4 ohm from the 12 mm Xmax the 8 ohm version is evidently going to boast?

OlogyAudio
07-26-2007, 03:53 AM
It looks like the 2 ohm version could very well be a winner. Especially in car audio. I'm not normally a fan of 2 ohm drivers, as people are not usually aware of the real differences between them, and the sacrifices a lower impedance driver has to make. However, it seems you're approaching it pretty well.

I think a driver like this, if it performs, will do very well, if cost can be kept down.

What kind of coil are you using? That magnet is huge. Is Xmax being limited by the cone, or the coil? What's difference with the 8 ohm version, and what is keeping the 2 ohm or 4 ohm from the 12 mm Xmax the 8 ohm version is evidently going to boast?

Ultimately depth is the restriction keeping the xmax down to 7mm on the 2/4 ohm units down from 12mm on the 8 ohm. The cone profile is a little on the deep side and the basket is quite substantial. I could see about sandwiching the motor up inside of the basket a few mm and I can look into a split coil design for this unit and try to squeeze as much xmax out of the depth and flux as possible, however I want to keep the xmax and xmech far enough apart (I won't run into people slamming a voice coil into steel too often that way).

Both the home and car versions are designed for high value.


As it stands the home version is an extended pole overhung driver. There is a short path in the motor that is a whopping 6mm thick as well.

Xmax is limited by the coil @ 7mm and its hard to say @12mm... I'll have to see :-D

Gary S
08-29-2007, 04:17 PM
Dylan - first of all, glad to see you here, and still working on this project... I'm sick and tired of mediocre, overpriced component speakers... let the component speaker wars begin.

About the ohm load... there are a couple things to consider:

1) Watts are cheap - car amplifiers are affordable these days... if people want more SPL, more power is in reach.

2) 4-ohm has become a standard, and as you pointed out, not much difference in the ohm load... to gain anything, you have to give something else up, so it's kind of a wash - no free lunch. Also, I think making them 2-ohm could cause confusion... there are too many people confused over car audio as it is.

3) On the other hand, gimmicks can sell... lots of people look for something different and ask for 2-ohm drivers.

I'm sure I will want a set either way. Keep up the good work and don't let anything stop you.