18" subwoofer or not?
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URL: https://forum.speakerplans.com/forum_posts.asp?TID=107183
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Topic: 18" subwoofer or not?
Posted By: Jack1991
Subject: 18" subwoofer or not?
Date Posted: 03 July 2022 at 4:49pm
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I got a small 12v sound system, for subs i use up to 4x Tham 12s. All 8Ω It runs off a car amplifier, Pioneer 8704. When running 4x thams the way its wired each sub recieves 50w (total 200w). When running just 2 subs the way its wired each sub gets 150w (total 300w) Id like to build 1x 18" sub to use instead sometimes, i know its alot heavier and bigger but be fun to build and looks alot nicer! Im just not sure on if it would sound better/louder/lower. Id only have to buy the speaker driver itself as the wood is offcuts from a friend. If i have just 1x 8Ω sub though then as far as im aware the only way i can wire it to that amplifier, it would only recieve 150w. I understand that 4x 12" speakers the surface area is greater than 1x 18" speaker. But im not sure if that works out the same way for if its say a 1850 horn sub because of the horn path etc? Also if it is worth me building one do you have a good suggestion for what one to build please? I had my eye on the 1850 but been reading around and see alot of people say the 1850 and 186 are pretty old now and there is better modern ones, but dont seem to say what ones they are. Cheers
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Replies:
Posted By: Line Array
Date Posted: 04 July 2022 at 3:46am
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where are you using this system - in a car ? outdoors ? small room ? large space ? ------------- best place on the internet >>> https://dissidentsound.discoursehosting.net |
Posted By: Jack1991
Date Posted: 04 July 2022 at 7:06am
| Outdoors |
Posted By: Jo bg
Date Posted: 04 July 2022 at 7:25am
| Consider a double 15 or double 12… you need efficiency on batteries, not a 18 with a lot of excursion you will not use. |
Posted By: Jack1991
Date Posted: 04 July 2022 at 8:51am
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Cool yeh ok, any particular plan or do you mean just design my own double reflex cabs?
The Tham12s are good i rekon but just wondered if theres anything else i could build that would be better.
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Posted By: eyeT
Date Posted: 04 July 2022 at 9:52am
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Two Tham 15? The 4r load on the amp works out well and the Tham 15's do deliver. |
Posted By: Jack1991
Date Posted: 04 July 2022 at 10:33am
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Cool yeh ive heard they are good. Was hoping for something different to a Tham though as got the 4 tham12s. Be nice to build and hear something different really. Plan would be to have 1 sub box and then 1 midtop. Thats why was thinking a 1850. But didnt know about the excursion.
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Posted By: fatfreddiescat
Date Posted: 04 July 2022 at 10:40am
| 1850 was designed to work in multiples, as are all but the immovable front loaded horns that do bass, I'm guessing the 4 thams 12's are going to be hard to beat for output within their design bandwidth with a single driver / cab. |
Posted By: smitske96
Date Posted: 04 July 2022 at 10:49am
| Do you want to go lower? Then maybe its worth looking at something like a keystone or xoc1 TH18. |
Posted By: Jack1991
Date Posted: 04 July 2022 at 12:15pm
Ah ok cool i did wonder if they were pointless using on their own. And yeh thought the tham12s may be best for what im using.
I guess it would be cool if it goes lower. Basically i just wanted to build 1 sub that would be louder or at least equal to (loudness) either the 2 or 4 tham 12s. If it goes lower that would be good too. Be nice to make something different and new and to hear how it sounds. Also nice to just have 1 box even if it is 1 bigger heavier box thats ok. I assumed to achieve this id need to go 18". That Xoc TH18 looks a beast! I like that. Not a fan of the look of the keystone.
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fatfreddiescat wrote:Posted By: eyeT
Date Posted: 04 July 2022 at 4:47pm
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I'll get shot down for this, maybe. But if yr looking for an immovable cab. What about a Jensen Imperial with a 4r driver? It is the Platinum Jubilee after all, 1952 design.... If you have the wood....
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Posted By: LjudLahger
Date Posted: 04 July 2022 at 8:41pm
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Upgrade the amp? What drivers in the thams?
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Posted By: Xoc1
Date Posted: 04 July 2022 at 10:27pm
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So if the amp is the GM-D8704 4-channel amplifierIt can be bridged to 2 channels 300 W x 2-Channel - 4 Ohm Bridged So with 2 x 8Ω per channel parallel to make 4 ohm they should get 150W each. 600 rms total. A single speaker would need a different amp as you would only get 200w @ 8Ω or 300w @ 4R. You have not said what drivers you are using but if they are decent I don't think what you have got is far from optimal. the Tham 12 responds well to being used in quads. As a single they are about 98 db at the bottom of their passband but seem to gain 11 db in a quad. A SS15 might be 100 102 db /W but only gain 10db In a quad. 4 X TH18 would not be louder than the 4 X SS15's but would have more bandwidth in a quad, so you would spend a lot for little gain. Obviously the bigger speakers would spank your little boxes, but only when given the power that they can handle. |
Posted By: Jack1991
Date Posted: 05 July 2022 at 7:41am
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It is that amplifier yes, but 2 channels are for the subs and the other 2 is, 1 for the mids, and 1 for the tops. But what i was thinking is if i had 1 sub box i could use 2 channels for that and then the other 2 channels for just a single mid top. Cheers for all the info though man, i think ill just stick with the Thams then. Its only a small 12v system which is surprisingly plenty loud enough for what ill ever use it for. Im more just getting the itch to build something again to be honest, something bigger that looked a bit more meaty.
The drivers in the Tham12s are only Thomann 12-280-W as i dont need big power so they are fine for it. |
Posted By: Xoc1
Date Posted: 05 July 2022 at 9:51pm
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The Thomann 12-280-W has no published speaker parameters. But I found some user generated ones that could be used in Hornresp. My suggestion to you is to get another amplifier to run the mid tops separately. Then you should get a decent output from the 4 Tham 12s as you could run 150w rms each cab. If you could run a proper crossover with a high pass than even better. Maybe a t.racks DSP 4x4 Mini would be a reasonable 12V digital crossover? Sim is unfiltered 4 X 12 -280/W at 150W each and a suitable high pass filter. |
Posted By: APW
Date Posted: 06 July 2022 at 8:41am
Data Sheet: https://images.thomann.de/pics/prod/283965_datenblatt.pdf" rel="nofollow - https://images.thomann.de/pics/prod/283965_datenblatt.pdf From the data sheet: Re: 6.6r
Fe: 36.035Hz Sd: 51.071m Md: 56.900g Bl: 20.681T Qms: 5.137 Qes: 0.316 Qts: 0.304 No: 1.274% Spl: 93.1dB Vas:75.663Ltr Cms: 204.291u M/N Krm: 4.949m Ohm Erm: 0.867 Mms: 85.706m Kg Mmd: 79.070m Kg Kxm: 44.11m H Exm: 0.716 |
Posted By: Jack1991
Date Posted: 06 July 2022 at 2:30pm
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Going to bin this idea now then and stick with the Thams. Thanks for all the advice and help though people 👍🏼
Out of interest though Xoc1, i have a T.racks 4x4 dsp mini which i use for it all. But if i was to get another amplifier say a 2 channel amplifier, 1 for mids, 1 for tops. I wouldnt be able to link that through the same dsp would I? As each channel on the amp requires a channel of the dsp? Or would i just have to use a rca splitter? Also do you have a good reccomendation for a high pass for the thams?
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Posted By: DMorison
Date Posted: 06 July 2022 at 3:08pm
If you're running mono, then you'd only need one channel of the DSP for however many channels of amp are feeding the bass section, one for the mids and one for the highs, so that would take up 3 (or 4 if you have a 4 way rig). You would need to put a splitter on the bass output of the DSP if you were feeding that to multiple amp channels, or use amps that have pass-through connections already.
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Posted By: Jack1991
Date Posted: 06 July 2022 at 3:21pm
Ahh right ok cool yeh that makes sense then. Not sure how id connect it though.  So yeh because my amp is a 4 channel, it has 1x rca input for each channel. So if 2x channels were bridged for 2x subs. Then the other 2x channels bridged for the other 2 subs. But all running the same frequency etc then im not sure how id connect that? The DSP inputs/outputs are all 1/4" jack. Or do you mean literally just 1 output of the dsp, to 1 input of the amp. That would do even if 2x channels are bridged?
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Posted By: DMorison
Date Posted: 06 July 2022 at 8:11pm
| The amp's manual should explain how to connect it up in the various operating modes it offers, but you may well need adapters or a custom cable to convert the balanced TRS output of the DSP to unbalanced RCQ to match the amp's inputs. |
Posted By: Xoc1
Date Posted: 06 July 2022 at 10:08pm
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https://www.pioneer-car.eu/uk/support/manuals/62996" rel="nofollow - https://www.pioneer-car.eu/uk/support/manuals/62996 RCA input jack A For two-channel output, connect the RCA plugs to the RCA input jack A with RCA pin plugs INPUT SELECT (input select) switch (2CH position) So just connect the LF outputs from the DSP to the GM-D8704, A inputs, throw the switch to 2 channel. Wire the Thams in parallel pairs (4 ohm loads) to the 2 bridge amp outputs - Its all in the Manual. RTFM Plug the DSP HF Outputs from the DSP thru a separate Amp.into the mid tops & I think you have a cost effective upgrade. |
Posted By: jacethebase
Date Posted: 06 July 2022 at 10:31pm
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Posted By: Jack1991
Date Posted: 07 July 2022 at 8:23am
| Cool, cheers guys thanks for the help. And yeh sorry man will RTFM in future, my bad. |
Posted By: fsp
Date Posted: 19 August 2022 at 9:33am
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yes of course , why not ? get a lot of 18 inch you can afford,,you life young just once so do best you can do |