Tedious Tuning (Active/passive 3-way front stage)
Thread Starter
Former Vendor
Joined: Nov 2005
Posts: 8,995
Likes: 2
From: Spring Texas
St. Jude Donor '08
Well my Alpine 17MB drivers seem to be dead. I'm going to get a pair of the Peerless woofers and try them out. If the perform as I hope they will, I'll have to re-build my fiberglass mounts since they're slightly bigger than my Alpines.
Thread Starter
Former Vendor
Joined: Nov 2005
Posts: 8,995
Likes: 2
From: Spring Texas
St. Jude Donor '08
Question: with my new Peerless midbass drivers, i'm thinking it's not that essential that they be angled as much as the midrange. If i scoot the mount for the midbass down and forward some, i can get more of the midrange shooting through the grille.
Good idea?
Good idea?
Melting Slicks
Joined: Dec 2004
Posts: 2,394
Likes: 0
From: Bay Area CA
What are your crossover points for both? Generally speaking, improving your path in the midrange is always beneficial, especially when dealing with a 3 way front stage and a true midbass driver that I would guess is operating in the 80hz - 350hz range at max., so you are not losing much information that is vocal based, especially in a frequency range that is not as "direcitonal" as the midrange, or tweets especially.
G'luck bro
Fej
G'luck bro
Fej
Last edited by fej; Mar 19, 2009 at 02:44 PM.
Thread Starter
Former Vendor
Joined: Nov 2005
Posts: 8,995
Likes: 2
From: Spring Texas
St. Jude Donor '08
What are your crossover points for both? Generally speaking, improving your path in the midrange is always beneficial, especially when dealing with a 3 way front stage and a true midbass driver that I would guess is operating in the 80hz - 350hz range at max., so you are not losing much information that is vocal based, especially in a frequency range that is not as "direcitonal" as the midrange, or tweets especially.
G'luck bro
Fej
G'luck bro
Fej
90hZ HPC 18dB slope
4kHz LPC 12dB slope
The passive crossover that divides the Midbass from the Midrange is set at 200hz. Accordign to the user manual: "LPF low Q semi second order HPF: 1st order" Not sure what that means but the graph is pretty
Melting Slicks
Joined: Dec 2004
Posts: 2,394
Likes: 0
From: Bay Area CA
Hmm, so the midrange is 200hz and up 6db slope, and the midbass is 200hz and down with somewhere in the 9db slope range. I think that is what that text is trying to say.
Either way it is a nice crossover point for a 3 way stage, and one of the real benefits of having a 5.25" midrange, you will get almost all of your vocal range from your midrange, which is as it should be
Fej
Either way it is a nice crossover point for a 3 way stage, and one of the real benefits of having a 5.25" midrange, you will get almost all of your vocal range from your midrange, which is as it should be
Fej
Team Owner
Joined: Feb 2000
Posts: 51,504
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From: Sacramento CA
They play such low frequencies... I think you'll be in good shape.
Thread Starter
Former Vendor
Joined: Nov 2005
Posts: 8,995
Likes: 2
From: Spring Texas
St. Jude Donor '08
Hmm, so the midrange is 200hz and up 6db slope, and the midbass is 200hz and down with somewhere in the 9db slope range. I think that is what that text is trying to say.
Either way it is a nice crossover point for a 3 way stage, and one of the real benefits of having a 5.25" midrange, you will get almost all of your vocal range from your midrange, which is as it should be
Fej
Either way it is a nice crossover point for a 3 way stage, and one of the real benefits of having a 5.25" midrange, you will get almost all of your vocal range from your midrange, which is as it should be
Fej
I assume the Peerless midbass will be at home without any type of enclosure as long as the mids are enclosed?
....i just need to find some sweater fleece....
Thread Starter
Former Vendor
Joined: Nov 2005
Posts: 8,995
Likes: 2
From: Spring Texas
St. Jude Donor '08
My midbass speakers arrived today. 
Initial out-of-mount testing revealed the same distortion problem as the "repaired" SPX 17MB problem. I thought for some reason i may have toasted my front stage amp. Since it's the same as the rear/tweeter amp, i swapped them and stillhave the problem. In a last ditch effort, ran a direct speaker wire from the front channel to the crossover and speakers. Still no fix.
Then I started tinkering with the SPX 17MB passive crossover. I found that by setting the "MB level" jumper from 0dB to +2 dB completely eliminates the distortion. I tested it on the repaired SPX 17MB and it was okay too.
The question i have remaining is this: My midrange plays 2-3 times louder than the midbass speaker. I re-set the GEQ to a flatline to make sure it wasn't a result of tuning. With the midrange disconnected, the midbass give me clean-powerful music but when the midrange is introduced to the MB crossover, the Midbass driver is drowned out completely.
The speakers power ratings are as follows:
SPX 137 woofer: 35w
SPX 17MB midbass: 40w
Peerless SLS 6.5: 50w
The Big question:
Is it normal for the midbass to play so quietly in comparison to the midrange?
I think for the time being, i'm going to run with my repaired SPX 17MB drivers. I don't have the time right now to completely redesign my door mounts. (perhaps in a month or so)
Initial out-of-mount testing revealed the same distortion problem as the "repaired" SPX 17MB problem. I thought for some reason i may have toasted my front stage amp. Since it's the same as the rear/tweeter amp, i swapped them and stillhave the problem. In a last ditch effort, ran a direct speaker wire from the front channel to the crossover and speakers. Still no fix.
Then I started tinkering with the SPX 17MB passive crossover. I found that by setting the "MB level" jumper from 0dB to +2 dB completely eliminates the distortion. I tested it on the repaired SPX 17MB and it was okay too.
The question i have remaining is this: My midrange plays 2-3 times louder than the midbass speaker. I re-set the GEQ to a flatline to make sure it wasn't a result of tuning. With the midrange disconnected, the midbass give me clean-powerful music but when the midrange is introduced to the MB crossover, the Midbass driver is drowned out completely.
The speakers power ratings are as follows:
SPX 137 woofer: 35w
SPX 17MB midbass: 40w
Peerless SLS 6.5: 50w
The Big question:
Is it normal for the midbass to play so quietly in comparison to the midrange?
I think for the time being, i'm going to run with my repaired SPX 17MB drivers. I don't have the time right now to completely redesign my door mounts. (perhaps in a month or so)
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Melting Slicks
Joined: Dec 2004
Posts: 2,394
Likes: 0
From: Bay Area CA
Few things going on, one is the efficiency of the driver, which I am sure is down at least 1db. So it needs 33% more power than the midrange to catch up. Secondly is that the human ear naturally hears best in the midrange, so you are working against that as well (somewhat minor in the grand scheme of things)
Playing well in the midbass range, where all of the engine/exhaust/road noise is, is the hardest thing to do in a car, and the range that you are operating in requires a fair amount of excursion, which in turn requires power. And the 50w you are throwing at it may just not be enough.
Kale ran 320w per side to his midbass at one point
, I ran 165 to mine in a 2 way set up in my truck, and currently run about 75w to the midbass in my vette 3 way setup with about 5% gain from minimum, and my midrange is at minimum.
G'luck
Fej
Playing well in the midbass range, where all of the engine/exhaust/road noise is, is the hardest thing to do in a car, and the range that you are operating in requires a fair amount of excursion, which in turn requires power. And the 50w you are throwing at it may just not be enough.
Kale ran 320w per side to his midbass at one point
, I ran 165 to mine in a 2 way set up in my truck, and currently run about 75w to the midbass in my vette 3 way setup with about 5% gain from minimum, and my midrange is at minimum.G'luck
Fej
Thread Starter
Former Vendor
Joined: Nov 2005
Posts: 8,995
Likes: 2
From: Spring Texas
St. Jude Donor '08
I found that the biggest factor was that i was doing out-of-enclosure testing. Once i mounted the original SPX in it's enclosure, the output increased significantly.
Granted I probably don't have that much power going to my setup: the midrange/midbass channel bridged is getting 100w RMS continuous power. The midrange's 35w and MB 40w (total 85) power handling means that the amp is just barily driving the speakers. I'm sure if i threw 200w at that channel I'd get much more out of them.
Perhaps in the next setup when I completely re-build everything I'll try for more power. PDX amps in a new custom fiberglass amp rack and completely re-designed door panels are part of that plan, but for now I'm happy with this setup.
Thank you guys for all your help.
BTW: I will be selling my brand-new never-mounted Peerless 830946 SLS 6.5" Woofers. List is $45/ea + shipping. I'll let them go for $100 shipped.
Granted I probably don't have that much power going to my setup: the midrange/midbass channel bridged is getting 100w RMS continuous power. The midrange's 35w and MB 40w (total 85) power handling means that the amp is just barily driving the speakers. I'm sure if i threw 200w at that channel I'd get much more out of them.
Perhaps in the next setup when I completely re-build everything I'll try for more power. PDX amps in a new custom fiberglass amp rack and completely re-designed door panels are part of that plan, but for now I'm happy with this setup.
Thank you guys for all your help.
BTW: I will be selling my brand-new never-mounted Peerless 830946 SLS 6.5" Woofers. List is $45/ea + shipping. I'll let them go for $100 shipped.
