Aiwa MA 3000 + Polk db840DVC Q. from newbie
Shackman
Posts: 6
Hi all. I am reproducing this Q. from where I posted it in the "Subwoofer Talk" section as maybe it has more application here. Hope some of you have some advice.
I have just upgraded my car stereo from the OEM cassette/radio to a nice new Kenwood system. The head unit is a 2008 model 22W RMS/ 50W peak times 4 (front and rear, L+R) CD/AM/FM job with provision for aux. in via a 3.5mm socket, (handy to plug your Zoom H4 in after recording a gig or band practice) and additionally a USB socket, so a USB stick full of mp3's works well and sounds great. Speakers are similarly new 6 1/2" 3 way in the doors and a couple of 6 by 9's on the parcel shelf, all Kenwood and all 4 ohm.
I feel however, as a bass player, that the bottom end is a bit lacking and no amount of bass emphasis using the standard EQ controls really compensates. So I've bought a Polk Audio subwoofer, model db840DVC. This is an 8 inch unit 4 ohm unit with a claimed capacity of 180W RMS and 360W peak. It utilises dual 4 ohm voice coils and consistent with that has 2 pairs of speaker terminals, one each opposite the other on the speaker basket. Claimed freq. range is 30hz to 200Khz and sensitivity is a claimed 85db at 1 watt (and I assume I meter- that's approx 39 " to you guys). The plan is to mount the subwoofer within the boot, or "trunk" as most of you guys would say, on to a conveniently placed circular depression at the rear of the parcel shelf in my '98 Mitsubishi Diamente, sold here in Australia as a "Magna". Whether I cut a hole of the appropriate diameter in that circular depression in the parcel shelf stamping for the sub to fire up through, or just drill it full of holes, I haven't yet decided. It doesn't look to be stress bearing, but I'm not sure. I'm prepared however to buy or make a sub woofer enclosure if nec, although the 840 manual says it needs to be about 9L in capacity- that's about 2 US gallons, as is thus a fair volume to lose from the boot ("trunK") plus a bit of added weight.
Powering the subwoofer will be a stand alone amp, one I have had lying around for years from a previous car stereo installation. It is an Awia
MA - 3000, a model dating from the early 90's when it was considered high powered. Specs are 35+35W RMS stereo/65+65W peak. It claims on the side of the unit "Matching Impedance 4-8 Ohms". I'm assuming that the quoted wattage figures relate to a 4 ohm load rather than 8 ohm. It is internally bridgeable with an external switch, from stereo to mono usage, and mono is obviously how I plan to use it, so in theory I should have 70W RMS/130W peak available. It is old but in good nick. it sounded great in its previous role as a stereo full range amp powering a pair of Voxson 6 by 9" 200W (peak) parcel shelf speakers.
Usage wise, I don't listen to "doof doof" music, as car-generated rap+techno is often characterized, but enjoy rock, jazz, pop and even orchestral. I'm not going for deafening volume, but headroom and a bit of bona fide thump. After all, I turn 53 this year!
The plan is to connect both of the amps output terminal pairs (ie. L+R) to the subs pair of speaker terminals. As the amp will be bridged it should deliver 35W RMS (max), across 4 ohm, to both coils. THe amp has an external sensitivity adjustment, and the head unit provides for independent subwoofer level adjustment
So much for the background. Now to the questions. (BTW, I've searched the Polk site to attempt to answer these Q.'s- no specific hard answers forthcoming so I am posting here.
Can anyone see problems with this proposition?
Is this insufficient power for the speaker, likely to lead to ugly clipping noises?
How does this wiring plan look to you?
Glad of any help,
Cheers,
John
I have just upgraded my car stereo from the OEM cassette/radio to a nice new Kenwood system. The head unit is a 2008 model 22W RMS/ 50W peak times 4 (front and rear, L+R) CD/AM/FM job with provision for aux. in via a 3.5mm socket, (handy to plug your Zoom H4 in after recording a gig or band practice) and additionally a USB socket, so a USB stick full of mp3's works well and sounds great. Speakers are similarly new 6 1/2" 3 way in the doors and a couple of 6 by 9's on the parcel shelf, all Kenwood and all 4 ohm.
I feel however, as a bass player, that the bottom end is a bit lacking and no amount of bass emphasis using the standard EQ controls really compensates. So I've bought a Polk Audio subwoofer, model db840DVC. This is an 8 inch unit 4 ohm unit with a claimed capacity of 180W RMS and 360W peak. It utilises dual 4 ohm voice coils and consistent with that has 2 pairs of speaker terminals, one each opposite the other on the speaker basket. Claimed freq. range is 30hz to 200Khz and sensitivity is a claimed 85db at 1 watt (and I assume I meter- that's approx 39 " to you guys). The plan is to mount the subwoofer within the boot, or "trunk" as most of you guys would say, on to a conveniently placed circular depression at the rear of the parcel shelf in my '98 Mitsubishi Diamente, sold here in Australia as a "Magna". Whether I cut a hole of the appropriate diameter in that circular depression in the parcel shelf stamping for the sub to fire up through, or just drill it full of holes, I haven't yet decided. It doesn't look to be stress bearing, but I'm not sure. I'm prepared however to buy or make a sub woofer enclosure if nec, although the 840 manual says it needs to be about 9L in capacity- that's about 2 US gallons, as is thus a fair volume to lose from the boot ("trunK") plus a bit of added weight.
Powering the subwoofer will be a stand alone amp, one I have had lying around for years from a previous car stereo installation. It is an Awia
MA - 3000, a model dating from the early 90's when it was considered high powered. Specs are 35+35W RMS stereo/65+65W peak. It claims on the side of the unit "Matching Impedance 4-8 Ohms". I'm assuming that the quoted wattage figures relate to a 4 ohm load rather than 8 ohm. It is internally bridgeable with an external switch, from stereo to mono usage, and mono is obviously how I plan to use it, so in theory I should have 70W RMS/130W peak available. It is old but in good nick. it sounded great in its previous role as a stereo full range amp powering a pair of Voxson 6 by 9" 200W (peak) parcel shelf speakers.
Usage wise, I don't listen to "doof doof" music, as car-generated rap+techno is often characterized, but enjoy rock, jazz, pop and even orchestral. I'm not going for deafening volume, but headroom and a bit of bona fide thump. After all, I turn 53 this year!
The plan is to connect both of the amps output terminal pairs (ie. L+R) to the subs pair of speaker terminals. As the amp will be bridged it should deliver 35W RMS (max), across 4 ohm, to both coils. THe amp has an external sensitivity adjustment, and the head unit provides for independent subwoofer level adjustment
So much for the background. Now to the questions. (BTW, I've searched the Polk site to attempt to answer these Q.'s- no specific hard answers forthcoming so I am posting here.
Can anyone see problems with this proposition?
Is this insufficient power for the speaker, likely to lead to ugly clipping noises?
How does this wiring plan look to you?
Glad of any help,
Cheers,
John
Post edited by Shackman on
Comments
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Looks like if you do not have any Polk gear they do not care to help you. I posted a question in the sub woofer thread earlier and it seems I will have to find some place else for help. I wish the CC forum was still around at least they would help no matter what kind of gear you had. I will probably be deleted or asked to leave. I just thought that maybe there were some people out there who liked to help others in need of advise. That will teach my redneck butt to think.
Bob -
The car audio game is no where near as big here as home audio. I usually forget that we even have a section for car audio...I've only posted in it a few times.
I don't think it's a matter of "not wanting to help".;)
Sorry, I can't help with your problem. I have basically no knowledge when it comes to car audio. I have an Alpine Type R setup with an Alpine head unit in my car...and it was installed by a company that does car audio installation. I don't really have any experience in that department.
Also...it appears that he posted the same question in the car subwoofer section. He's gotten a few replies there. Just so ya know.;)
By the way, welcome to Club Polk.:)The nirvana inducer-
APC H10 Power Conditioner
Marantz UD5005 universal player
Parasound Halo P5 preamp
Parasound HCA-1200II power amp
PolkAudio LSi9's/PolkAudio SDA 2A's/PolkAudio Monitor 7A's
Audioquest Speaker Cables and IC's -
So do you know anything about hooking up a home sub woofer? I posted in the sub woofer thread and need some help.
Bob -
Oops I am in the subwoofer thread.
