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18" subwoofer or not? |
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Xoc1 ![]() Registered User ![]() Joined: 15 October 2012 Location: Devon UK Status: Offline Points: 338 |
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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. |
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Jack1991 ![]() Registered User ![]() Joined: 05 February 2020 Location: Bristol Status: Offline Points: 454 |
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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. Edited by Jack1991 - 05 July 2022 at 7:48am |
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Xoc1 ![]() Registered User ![]() Joined: 15 October 2012 Location: Devon UK Status: Offline Points: 338 |
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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. |
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APW ![]() Young Croc ![]() ![]() Joined: 13 November 2012 Location: Kent, UK Status: Offline Points: 1137 |
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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 Edited by APW - 06 July 2022 at 8:51am |
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Jack1991 ![]() Registered User ![]() Joined: 05 February 2020 Location: Bristol Status: Offline Points: 454 |
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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?
Edited by Jack1991 - 06 July 2022 at 2:40pm |
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DMorison ![]() Old Croc ![]() Joined: 14 March 2007 Location: Aberdeen Status: Offline Points: 1584 |
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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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Jack1991 ![]() Registered User ![]() Joined: 05 February 2020 Location: Bristol Status: Offline Points: 454 |
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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?
Edited by Jack1991 - 06 July 2022 at 3:23pm |
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DMorison ![]() Old Croc ![]() Joined: 14 March 2007 Location: Aberdeen Status: Offline Points: 1584 |
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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.
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Xoc1 ![]() Registered User ![]() Joined: 15 October 2012 Location: Devon UK Status: Offline Points: 338 |
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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. |
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jacethebase ![]() Old Croc ![]() ![]() Joined: 23 September 2009 Location: Somerset Status: Offline Points: 5679 |
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I have said it before and I will say it again.
There is no replacement for displacement!
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www.wedding-production.co.uk
www.stage2sound.com |
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Jack1991 ![]() Registered User ![]() Joined: 05 February 2020 Location: Bristol Status: Offline Points: 454 |
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Cool, cheers guys thanks for the help. And yeh sorry man will RTFM in future, my bad.
Edited by Jack1991 - 07 July 2022 at 8:23am |
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fsp ![]() New Member ![]() ![]() Joined: 19 August 2022 Status: Offline Points: 2 |
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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 |
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