4-8s versus 1-15"
11-08-2003, 04:15 PM
#1
1000 Watt CAFz'r
Thread Starter
Join Date: Oct 2003
Posts: 1,783
I’m going to tell a little story, get a pillow if you need one.
This past week I’ve had the opportunity to test 2 subwoofer configurations in my car. My car has 4 Focal 21V2 8” subs installed in separate13 liter sealed enclosures for each driver. All 4 subs are wired in parallel giving a 1 ohm load to my amplifier. The “test” subwoofer was an Adire Audio Brahma 15 in an approximately 2+ cubic foot enclosure. I don’t know the exact volume, but for this test it proved to be adequate for my evaluation. Before you woofer gurus jump in and start preaching about box volume, I’d like to say that the Brahma could have sounded better in a properly tuned box. My test, however, was focused on the driver’s ability to reproduce dynamics, not tonal balance or SPL. The Brahma had both it’s voice coils in parallel producing an equal 1 ohm load on my amplifier.
The cone area for the 2 setups was really close. The Focal 21V2 has a cone area of 189 sq. cm each for a total of 756 sq. cm for the 4 combined. The Adire Audio Brahma has a cone area of 749 sq. cm. Pretty darn close in my book.
So here we have 2 subwoofer setups with similar cone area loading the exact same amplifier with pretty well the same impedance load.( Reactive impedance would be a bit different)
The amplifier used was my Audison VRx1.500. It was connected to 2 Optima yellow tops with 2- 1 farad capacitors hooked up to the capacitor input terminal on the amp. Loaded at 1 ohm, it puts out 2000 watts RMS. Both subwoofer setups were crossed over at 80 Hz and had a 30hz subsonic filter applied.
The Adire Audio Brahma is one mean subwoofer. I haven’t had the opportunity to test this sub enough to clearly evaluate it’s potential in my SQ setup, but I will say that it plays pretty loud and deep. Transients are NOT its strong point. It plays tones very strongly. Bass guitar and techno tone sweeps are very firm, but impacts and kick drums are a bit weak for my taste. I best describe it as a lack of speed.
The 4 Focal 8s are very fast. I’m not new to using small drivers for bass, and this is where small drivers show their speed. The 8s don’t play as strong deep down as the Brahma (mostly due to less cone excursion-Brahma Xmax about 20mm verses the 21V2 Xmas of 9mm) but they certainly don’t leave you disappointed down low. They can play the low notes, just not with the authority of the Brahma. Transients are on a completely different level with the 8s. The speed and impact is breath taking. This is my kind of bass, with kick drums leaving a firm imprint on your chest. Putting 500 watts RMS to each 8” sub will do that though.
So without getting too technical or analytical of each subwoofer setup, I hope you have an idea of what the differences are to your ears. I’ve always loved really deep earth-shaking bass, but I’m a sucker for the tight stuff. What I’d really love to do would be to use the 15 below 40hz and the 8s above. But then of course I’d lose my back seat and have to add another amplifier.
What I’d really love to try would be 16 of the Focal 5WS mini subwoofers. Of course I’m sure a few of you are snickering right now about a 5 ¼ “ subwoofer.
Adam
This past week I’ve had the opportunity to test 2 subwoofer configurations in my car. My car has 4 Focal 21V2 8” subs installed in separate13 liter sealed enclosures for each driver. All 4 subs are wired in parallel giving a 1 ohm load to my amplifier. The “test” subwoofer was an Adire Audio Brahma 15 in an approximately 2+ cubic foot enclosure. I don’t know the exact volume, but for this test it proved to be adequate for my evaluation. Before you woofer gurus jump in and start preaching about box volume, I’d like to say that the Brahma could have sounded better in a properly tuned box. My test, however, was focused on the driver’s ability to reproduce dynamics, not tonal balance or SPL. The Brahma had both it’s voice coils in parallel producing an equal 1 ohm load on my amplifier.
The cone area for the 2 setups was really close. The Focal 21V2 has a cone area of 189 sq. cm each for a total of 756 sq. cm for the 4 combined. The Adire Audio Brahma has a cone area of 749 sq. cm. Pretty darn close in my book.
So here we have 2 subwoofer setups with similar cone area loading the exact same amplifier with pretty well the same impedance load.( Reactive impedance would be a bit different)
The amplifier used was my Audison VRx1.500. It was connected to 2 Optima yellow tops with 2- 1 farad capacitors hooked up to the capacitor input terminal on the amp. Loaded at 1 ohm, it puts out 2000 watts RMS. Both subwoofer setups were crossed over at 80 Hz and had a 30hz subsonic filter applied.
The Adire Audio Brahma is one mean subwoofer. I haven’t had the opportunity to test this sub enough to clearly evaluate it’s potential in my SQ setup, but I will say that it plays pretty loud and deep. Transients are NOT its strong point. It plays tones very strongly. Bass guitar and techno tone sweeps are very firm, but impacts and kick drums are a bit weak for my taste. I best describe it as a lack of speed.
The 4 Focal 8s are very fast. I’m not new to using small drivers for bass, and this is where small drivers show their speed. The 8s don’t play as strong deep down as the Brahma (mostly due to less cone excursion-Brahma Xmax about 20mm verses the 21V2 Xmas of 9mm) but they certainly don’t leave you disappointed down low. They can play the low notes, just not with the authority of the Brahma. Transients are on a completely different level with the 8s. The speed and impact is breath taking. This is my kind of bass, with kick drums leaving a firm imprint on your chest. Putting 500 watts RMS to each 8” sub will do that though.
So without getting too technical or analytical of each subwoofer setup, I hope you have an idea of what the differences are to your ears. I’ve always loved really deep earth-shaking bass, but I’m a sucker for the tight stuff. What I’d really love to do would be to use the 15 below 40hz and the 8s above. But then of course I’d lose my back seat and have to add another amplifier.
What I’d really love to try would be 16 of the Focal 5WS mini subwoofers. Of course I’m sure a few of you are snickering right now about a 5 ¼ “ subwoofer.
Adam
11-08-2003, 06:13 PM
#2
500 Watt CAFz'r
Join Date: Apr 2001
Posts: 774
Originally posted by PEI330Ci:
I’m going to tell a little story, get a pillow if you need one.
The Adire Audio Brahma is one mean subwoofer. I haven’t had the opportunity to test this sub enough to clearly evaluate it’s potential in my SQ setup, but I will say that it plays pretty loud and deep. Transients are NOT its strong point. It plays tones very strongly. Bass guitar and techno tone sweeps are very firm, but impacts and kick drums are a bit weak for my taste. I best describe it as a lack of speed.
The 4 Focal 8s are very fast. I’m not new to using small drivers for bass, and this is where small drivers show their speed. The 8s don’t play as strong deep down as the Brahma (mostly due to less cone excursion-Brahma Xmax about 20mm verses the 21V2 Xmas of 9mm) but they certainly don’t leave you disappointed down low. They can play the low notes, just not with the authority of the Brahma. Transients are on a completely different level with the 8s. The speed and impact is breath taking. This is my kind of bass, with kick drums leaving a firm imprint on your chest. Putting 500 watts RMS to each 8” sub will do that though.
Adam
I’m going to tell a little story, get a pillow if you need one.
The Adire Audio Brahma is one mean subwoofer. I haven’t had the opportunity to test this sub enough to clearly evaluate it’s potential in my SQ setup, but I will say that it plays pretty loud and deep. Transients are NOT its strong point. It plays tones very strongly. Bass guitar and techno tone sweeps are very firm, but impacts and kick drums are a bit weak for my taste. I best describe it as a lack of speed.
The 4 Focal 8s are very fast. I’m not new to using small drivers for bass, and this is where small drivers show their speed. The 8s don’t play as strong deep down as the Brahma (mostly due to less cone excursion-Brahma Xmax about 20mm verses the 21V2 Xmas of 9mm) but they certainly don’t leave you disappointed down low. They can play the low notes, just not with the authority of the Brahma. Transients are on a completely different level with the 8s. The speed and impact is breath taking. This is my kind of bass, with kick drums leaving a firm imprint on your chest. Putting 500 watts RMS to each 8” sub will do that though.
Adam
I own a Focal 33VX (it lives in a properly built box recommended by Focal) and it is the best sub that I have ever heard. It is fast and tight while playing all the really low notes with authority.
Proper enclosures are KEY to getting great subbass.
11-08-2003, 07:11 PM
#3
So you have four 8's in the appropriate enclosure for sq and then use what you describe as an "adequate" box for the Brahma and then crap on it's transient response abilities?
Maybe you could contact Adire regarding specs for a sq box for the Brahma and THEN post the comparison.
Maybe you could contact Adire regarding specs for a sq box for the Brahma and THEN post the comparison.
11-09-2003, 06:34 PM
#5
500 Watt CAFz'r
Join Date: Jul 2003
Posts: 756
[img]graemlins/thumb.gif[/img] great review..
I have also liked smaller drivers for their ability to deliver those fast 'kick you in the pants' notes. I have usually wound up being disappointed overall though. There are characteristics of 12+" woofers that have always appealed to me. I have never really tried multiple small drivers (like 4 in your case) which sounds like it would certainly make up for the lack of excursion and output of a small driver. I recently purchased an IDQ15 which will be interesting. I certainly don't expect it to hit like an 8, but I'm hoping for reasonably quick response, and high output at very low frequencies. In my previous installs, I have almost always used 10" drivers in sealed enclosures.
Wow, 500 watts each is quite a bit. Have you measured maximum SPL with the four 8's ? I'm curious to see.
I have also liked smaller drivers for their ability to deliver those fast 'kick you in the pants' notes. I have usually wound up being disappointed overall though. There are characteristics of 12+" woofers that have always appealed to me. I have never really tried multiple small drivers (like 4 in your case) which sounds like it would certainly make up for the lack of excursion and output of a small driver. I recently purchased an IDQ15 which will be interesting. I certainly don't expect it to hit like an 8, but I'm hoping for reasonably quick response, and high output at very low frequencies. In my previous installs, I have almost always used 10" drivers in sealed enclosures.
Wow, 500 watts each is quite a bit. Have you measured maximum SPL with the four 8's ? I'm curious to see.
11-10-2003, 06:41 AM
#7
1000 Watt CAFz'r
Join Date: May 2002
Posts: 1,649
You can have it all.............. it's called a 3-way front stage with a single 12" or 15" sub. A 6.5" or 8" front component set will give you that fast and aggressive low end in the midbass region while the sub picks up the duties in the lower end.
11-10-2003, 07:56 AM
#8
50 Watt CAFz'r
Join Date: Aug 2003
Posts: 83
hehe.... don't like my brahma eh adam [img]tongue.gif[/img]
the 4 8's are impressive in your car but there are a few more things to factor in as well.
8's are in their proper enclosure.
you've spent alot of time tweaking the system with the 8's.
we spent about 10 minutes with the brahma
the box the brahma was in is... undersized to say the least.
i'm very very impressed with the brahma. Just wish it was a 12" and i could utilize it in my car better.
It's for sale in the for sale section if anyones interested [img]smile.gif[/img]
the 4 8's are impressive in your car but there are a few more things to factor in as well.
8's are in their proper enclosure.
you've spent alot of time tweaking the system with the 8's.
we spent about 10 minutes with the brahma
the box the brahma was in is... undersized to say the least.
i'm very very impressed with the brahma. Just wish it was a 12" and i could utilize it in my car better.
It's for sale in the for sale section if anyones interested [img]smile.gif[/img]
11-10-2003, 08:05 AM
#9
1000 Watt CAFz'r
Thread Starter
Join Date: Oct 2003
Posts: 1,783
There is a car in Calgary with 2 Focal 21V2 subs in about a 40 liter enclosure being driven off of an Audison VRx amp. That car convinced me to buy the 8s. I've also heard the Focal 33V2, 33KX, and 33WX subs.
Everybody here is going to have slightly different subwoofer tastes and needs. My little test was just for fun. I'll probably do many more with every possible configuration I can imagine. I have access to a lot of drivers. I think everybody should play like this once in a while. I find that I need to prove that I've made the right decision with equipment every now and again. Sometimes I'm proven wrong, then of course it's upgrade time. My point is that you really don't know how something will sound until you try it in person. Specs and figures will only take you so far.
With regards to box volume, the recomended box volumes for my 8s range from 10 to 20 liters. I can tell you from experience that decreasing the box volume from 20 liters will gradually roll off the very low end. The 13 liters I chose was a compromise to fit the subs in my car where I wanted them. Besides, I think that I can make up for the low end roll off with a little EQing, I've obviousely got the power. Adire recomends anything from 1.25 to 2.5 cubic feet for the Brahma 15. A bit above 2 cubic feet clearly pushes it into the SQ range of it's potential.
8Trackboy, send me an 8 track. We can be team-mates. [img]tongue.gif[/img]
500 watts is TOO MUCH! I don't recomend this much power to people with this driver unless they are very aware of the damage it can do. The 8s are mounted in my rear deck; I can see the suspension travel at high volumes. I also don't play music at full volume for very long.(1-2 minutes max) How loud are they? I don't know, but I'll find out some day and let you all know. The disadvantage in mounting the drivers in the rear deck is that I don't get any "corner gain". I'm sure most of you are familiar with the gain in SPL from putting subs facing backwards in the trunk. I chose to put the subs inside the passenger compartment to maximize audible speed. You home audiophiles will understand this more.
As Tom already knows, I have a 3-way front stage with 6.5" bass drivers. So does he last time I checked. What I believe Tom is talking about is crossing over the front stage pretty low, in the 50 Hz region. Then he'd put that 18" Eclipse sub he's been drooling over in the trunk of his "Truck". [img]tongue.gif[/img]
Ultimately, I want all of my speakers to disappear. What I mean is that I don't want to be concious of where any of my drivers are. Playing with the subwoofer cross-over frequency is a pretty good way of finding out where the subs disappear frequency wise. Unfortunately, it's only one of the ways to tune your system. I've been playing with my X.O. frequency, and have gotten close. Next up is the "time" domain...
I'm sure a few of you are tired of my pursuit of perfect phase, so I'll sign off now.
Adam
Everybody here is going to have slightly different subwoofer tastes and needs. My little test was just for fun. I'll probably do many more with every possible configuration I can imagine. I have access to a lot of drivers. I think everybody should play like this once in a while. I find that I need to prove that I've made the right decision with equipment every now and again. Sometimes I'm proven wrong, then of course it's upgrade time. My point is that you really don't know how something will sound until you try it in person. Specs and figures will only take you so far.
With regards to box volume, the recomended box volumes for my 8s range from 10 to 20 liters. I can tell you from experience that decreasing the box volume from 20 liters will gradually roll off the very low end. The 13 liters I chose was a compromise to fit the subs in my car where I wanted them. Besides, I think that I can make up for the low end roll off with a little EQing, I've obviousely got the power. Adire recomends anything from 1.25 to 2.5 cubic feet for the Brahma 15. A bit above 2 cubic feet clearly pushes it into the SQ range of it's potential.
8Trackboy, send me an 8 track. We can be team-mates. [img]tongue.gif[/img]
500 watts is TOO MUCH! I don't recomend this much power to people with this driver unless they are very aware of the damage it can do. The 8s are mounted in my rear deck; I can see the suspension travel at high volumes. I also don't play music at full volume for very long.(1-2 minutes max) How loud are they? I don't know, but I'll find out some day and let you all know. The disadvantage in mounting the drivers in the rear deck is that I don't get any "corner gain". I'm sure most of you are familiar with the gain in SPL from putting subs facing backwards in the trunk. I chose to put the subs inside the passenger compartment to maximize audible speed. You home audiophiles will understand this more.
As Tom already knows, I have a 3-way front stage with 6.5" bass drivers. So does he last time I checked. What I believe Tom is talking about is crossing over the front stage pretty low, in the 50 Hz region. Then he'd put that 18" Eclipse sub he's been drooling over in the trunk of his "Truck". [img]tongue.gif[/img]
Ultimately, I want all of my speakers to disappear. What I mean is that I don't want to be concious of where any of my drivers are. Playing with the subwoofer cross-over frequency is a pretty good way of finding out where the subs disappear frequency wise. Unfortunately, it's only one of the ways to tune your system. I've been playing with my X.O. frequency, and have gotten close. Next up is the "time" domain...
I'm sure a few of you are tired of my pursuit of perfect phase, so I'll sign off now.
Adam
11-10-2003, 08:39 AM
#10
1000 Watt CAFz'r
Thread Starter
Join Date: Oct 2003
Posts: 1,783
Fuel37 is right, we barely popped the Brahma in my car for a quick listen. With an optimized box and eq setup, the Brahma could sound way better. I'm not saying that it is a bad sounding sub. (I'm still very strongly considering buying one to keep playing with) What I wanted to emphasize is that different size woofers will bring certain inherent characteristics to their sound.
I'd probably consider doing what Tom is talking about with the Brahma if I wasn't so hypnotized by my 8s.
Adam
I'd probably consider doing what Tom is talking about with the Brahma if I wasn't so hypnotized by my 8s.
Adam
