"Detuned" 4x12 and an 18W

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colossal
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"Detuned" 4x12 and an 18W

Postby colossal » Sun 06/30/19 4:19 pm

For about six years, I've had a '69 Slant 4x12 loaded with a pair of 16Ω Scumback 65W M75-PVC on top and a pair of 16Ω 65W H75-PVCs on the bottom. It is wired series parallel for 16ohms, has a phase-flip switch, and was used primarily as a reference for when I was building and testing Plexis and other amps and needed to be able to handle some power. These days, it spends much of its time in its box, quietly hoping to come back into service one day :( With an 18W, it sounds congested and flat, facey, and with a thumpy low end that isn't really complimentary. To me, it's not really a good match and not the sound I am going for personally.

I love the clarity and almost three dimensional quality of an 18W combo with a low wattage Greenback. It's just a stunning combination and really hard to beat. I should clarify that I don't often play these amps to where they are really distorting. I like to get them cooking to where they come alive. If the neighbors are out, I will push it a bit. I prefer to plug straight in and use the Vol and Tone pots. I have tried a bunch of speakers and to my ear the Celestion Heritage 20W is a killer speaker and perfect match. However, I find with that speaker, the combo cab does not handle the low end of the Normal channel all that well and the low midrange gets a little blurry. I love the sound of the Normal channel but I have been wanting to tighten that low end just a hair but not go to a heavier speaker as I like that blur, but just want a little bit more tightness. It's really just a very small thing.

Today, I decided to mess around with so-called "detuning" method described by Kevin O'Connor et al where a speaker(s) is removed from the cabinet and operated normally (with the appropriate change in impedance, if needed). I got out the 4x12 and tried the following:

1. Removed the bottom two H75s and wired the upper pair of M75s for 8R.
2. Paired one M75 and one H75 in upper holes.
3. Paired on M75 and one H75 diagonally.
4. Paired both M75s diagonally.
5. Pared one M75 (upper) with Celestion 20W Heritage G12M (lower) diagonally.

Here is what I found:

1. There is a huge difference in the quality of the sound between a fully loaded 4x12 and a "detuned" 4x12 where two of the four speakers are removed.

2. A phase switch on the amp or cab is very useful. You need to find the right phase.

3. The detuned sound gains breadth and air and becomes much "tighter". The low end is massive. Just huge. I play Les Pauls with underwound, unpotted pickups and let me tell you, running an 18W into this sounds like a piano. With any of the speaker combinations I tried, the low E string attack is greatly improved with more of a percussive quality. You hear the characteristic woody quality of the cab but it doesn't have the "bloated beam" low end of a fully loaded 4x12.

4. The low end that is a bit soft and blurry in the standard 1x12 combo is thick, punchy, and articulate with the detuned 4x12. The mids are clear and defined. Everything is well separated with no one frequency dominating. The Tone control on the amp becomes even more sensitive.

5. The detuned cab sound is very omnidirectional. Very satisfying. It's more of what you love. You can walk in an arc in front and experience a nice "bubble" effect that is pleasantly loud and full. You can even turn it way down to TV level and it's warm and full.

6. I much preferred the sound with the speakers mounted diagonally. I went back and forth between side-by-side mounting and diagonal mounting, and for me, diagonal was the way to go. It was more balanced and wider sounding. I can see where side-by-side in a band situation would be useful as you get that extra bit of focus aimed at your head. But for my purposes, I'm going for that super-organic-3D-reverby-sound-from-everywhere adjective soup sound.

7. Out of the combinations I tried, I ultimately preferred two M75s mounted diagonally. The H75s do that Hendrix thing; my ear picks out that "thing" they do immediately. With the M75 and H75 mix, the H75 tended to dominate the mix a little too much for me. The H75 added some more bell-like top end, but I found the lower mids to be a bit too stiff and "up front". I could see this being spectacular for a Strat though where you want that syrupy, glassy Marshall sound. There is plenty of low end with the detuned cab, even with coupling caps at 10nF! Plenty! With the M75s, there is a killer balance of tight, articulate low end and chime.

8. Detuning does a very cool thing and "works". You have to try this for yourself if you've read about it and been curious. Some might consider the sound a little too hi-fi (maybe?) for their tastes. It is a very big, honest, and revealing sound. I am also running two 65W M75s so it does take a bit more to little more to get them breathing than the 20 watter, but man, they are really, really great sounding and very close to that 20W Heritage.

So in conclusion... hurray

EDIT: I didn't mean to imply that this was "better" than an 18W combo. Just different. After writing all this, I went back to the 1x12 combo with the 16R 20W Heritage G12M, turned it up, and man, that is a glorious, pure sound...
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Re: "Detuned" 4x12 and an 18W

Postby JMPGuitars » Sun 06/30/19 5:47 pm

Good stuff! I think you figured out my secret; I use a 2x12 cab with a single speaker mounted at 16 ohms. It sounds delicious. 8)

BTW- there's nothing hi-fi about doing this. The only part of your setup that leans that direction is that the speaker wattage is too high, so speaker distortion is generally eliminated.

With the 20W greenback, distortion is contributing to the overall overdrive tone because the amp has enough power to properly drive that speaker.

I've used 20W to 150W speakers with an 18W amp, and they all sound good in their own way as long as the speaker's tone curve can work with the amp. Personally I do like the speaker to be lower wattage, but I think my current speaker is 50W.

Thanks,
Josh
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Re: "Detuned" 4x12 and an 18W

Postby colossal » Sun 06/30/19 6:32 pm

JMPGuitars wrote:
Sun 06/30/19 5:47 pm
Good stuff! I think you figured out my secret; I use a 2x12 cab with a single speaker mounted at 16 ohms. It sounds delicious. 8)
I prefer 16 ohms as well. To continue with this 4x12, I would get a pair of 8 ohm speakers and wire in series for 16.
BTW- there's nothing hi-fi about doing this. The only part of your setup that leans that direction is that the speaker wattage is too high, so speaker distortion is generally eliminated.
Yeah, exactly. But the detuned approach is very revealing so some guys might find that too "hi-fi" for lack of a better name for their taste or playing style. Personally I love the articulate nature of it. Even with the 65W M75s, they start to breathe pretty quickly and that midrange wets out and the magic starts. The power amp can drive them pretty well.
With the 20W greenback, distortion is contributing to the overall overdrive tone because the amp has enough power to properly drive that speaker.
Yeah, I do prefer the low wattage speaker because it is incredibly sensitive, warm, and detailed.
I've used 20W to 150W speakers with an 18W amp, and they all sound good in their own way as long as the speaker's tone curve can work with the amp. Personally I do like the speaker to be lower wattage, but I think my current speaker is 50W.

Thanks,
Josh
I am sorely tempted to order a pair of 8R Blues and/or a pair of 20W M75-PVCs or 20W G12Ms to try with this 4x12 :lol:
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Re: "Detuned" 4x12 and an 18W

Postby JMPGuitars » Sun 06/30/19 8:22 pm

colossal wrote:
Sun 06/30/19 6:32 pm
I am sorely tempted to order a pair of 8R Blues and/or a pair of 20W M75-PVCs or 20W G12Ms to try with this 4x12 :lol:
Personally, I stay away from Scumback. He was a total scumbag to me regarding the only speaker I ever got from them, and it was defective. If you want boutique, take a look at Tone Tubby instead.

I think the speaker I have loaded right now is an Eminence Red Fang Alnico 12" which I think is fairly similar to a Celestion Alnico Blue. I like Eminence better than the new production Celestion stuff.

If I was in your situation, I would look for a couple low watt greenback equivalents, or the combo of a greenback ceramic, and a lower watt alnico. ...or try the Tone Tubby low watt Humbolt series. I've been interested in trying them for a while, but I have too many speakers already. ;)

Thanks,
Josh
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Re: "Detuned" 4x12 and an 18W

Postby colossal » Mon 07/01/19 7:30 am

JMPGuitars wrote:
Sun 06/30/19 8:22 pm
Personally, I stay away from Scumback. He was a total scumbag to me regarding the only speaker I ever got from them, and it was defective. If you want boutique, take a look at Tone Tubby instead.
Sorry to hear you had a bad experience. I've had mine for almost six years. As for Tone Tubby, I haven't taken the plunge on any of their products because they have almost no (good) example recordings out there, have ninety flavors of hempcone (with almost no descriptions to explain the subtleties), and some of them are going for crazy money now (the Rose series? $$). It's not so much the money as I believe in quality, I just need to hear something that sets them apart from what my ear is looking for (honestly, an Ipswich Celestion Blue or a 20W Heritage G12M is at the top of a short list for me). What I have heard of hemp cones is that they are a little darker, but honestly, that is only based on some recordings I heard a long time ago. I think I heard a Tone Tubby demo with Carlos Santana once and I am not, repeat NOT, into his sound :lol: I wish Tone Tubby would get some really good recordings done of their offerings and organize their site.
I think the speaker I have loaded right now is an Eminence Red Fang Alnico 12" which I think is fairly similar to a Celestion Alnico Blue. I like Eminence better than the new production Celestion stuff.
Interesting. I'll have to check them out. I've heard some Eminence speakers that I liked. As an aside, a fellow I built an 18W combo for wanted to shed a little weight in the combo. He pulled the G12H30 55Hz he had in there for a Jensen Tornado 65W neodymium. It actually sounds fantastic with the amp.
If I was in your situation, I would look for a couple low watt greenback equivalents, or the combo of a greenback ceramic, and a lower watt alnico. ...or try the Tone Tubby low watt Humbolt series. I've been interested in trying them for a while, but I have too many speakers already. ;)

Thanks,
Josh
Hahaha, way ahead of ya. I actually have a pair of 20W 8Ω Heritages coming 8) for 16 ohms in this 4x12 setup. They are now out of production too. Oddly, I was looking at Tone Tubby the other day and saw the Humboldts.
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Re: "Detuned" 4x12 and an 18W

Postby JMPGuitars » Mon 07/01/19 8:00 am

Tone Tubby's website does suck, but they have descriptions in there for most of them. There's also a TINY link on most of the speaker pages with links to youtube demos.

Regarding the hemp cone, I think it's only darker during the break-in period. That's not a bad thing anyway with 18watt amps, as they can often be bright. That's why V30s sound terrible with them. I had a TT 40/40 speaker that would have been too bright for an 18watter. It didn't sound dark at all.

Eminence has a line of neodymium speakers too. I haven't used them, but maybe one day if I ever get through the rest of my speakers. ;)

If you've got some Ipswich 20W speakers coming, I'm guessing you'll be happy. Post a demo once you have it setup, I'd love to hear it.
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Re: "Detuned" 4x12 and an 18W

Postby colossal » Mon 07/01/19 8:53 am

JMPGuitars wrote:
Mon 07/01/19 8:00 am
Tone Tubby's website does suck, but they have descriptions in there for most of them. There's also a TINY link on most of the speaker pages with links to youtube demos.

Regarding the hemp cone, I think it's only darker during the break-in period. That's not a bad thing anyway with 18watt amps, as they can often be bright. That's why V30s sound terrible with them. I had a TT 40/40 speaker that would have been too bright for an 18watter. It didn't sound dark at all.
Yeah, honestly I need to do more diligence on them. The guys on the Trinity forum praise the Tone Tubby Red and some of the others. I actually welcome some brightness as I play Les Pauls, but I have found my 18W builds to be quite mellow and well balanced.
If you've got some Ipswich 20W speakers coming, I'm guessing you'll be happy. Post a demo once you have it setup, I'd love to hear it.
I'll try to cobble something together.
JMPGuitars wrote:
Sun 06/30/19 5:47 pm
Good stuff! I think you figured out my secret; I use a 2x12 cab with a single speaker mounted at 16 ohms. It sounds delicious. 8)
If you don't mind my asking, what do you like for a 2x12 enclosure with your setup? Do you go with a vertical cab or horizontal? Are you sticking to Kevin O'Connor's dimensions or just taking, say, a Bluesbreaker 2x12 closing off the back completely and only loading the one 16 ohm speaker?
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Re: "Detuned" 4x12 and an 18W

Postby crgfrench » Mon 07/01/19 9:05 am

Hendrix, Page, Clapton, Beck, Trower, SRV ...they didn't use tone tubby, scumback, weber or WGS speakers. Come to think of it, they didn't use Sozo caps or Mercury Mag iron either. I feel like there is a lot of hype in this field?
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Re: "Detuned" 4x12 and an 18W

Postby JMPGuitars » Mon 07/01/19 9:13 am

colossal wrote:
Mon 07/01/19 8:53 am
JMPGuitars wrote:
Sun 06/30/19 5:47 pm
Good stuff! I think you figured out my secret; I use a 2x12 cab with a single speaker mounted at 16 ohms. It sounds delicious. 8)
If you don't mind my asking, what do you like for a 2x12 enclosure with your setup? Do you go with a vertical cab or horizontal? Are you sticking to Kevin O'Connor's dimensions or just taking, say, a Bluesbreaker 2x12 closing off the back completely and only loading the one 16 ohm speaker?
I have a mojotone vertical 2x12 I had custom made. I'm not a fan of their kit layouts (soooo many posts fixing that stuff on here), but I like their cabinets. Here's a photo:

DSC05525.jpg

Thanks,
Josh
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Re: "Detuned" 4x12 and an 18W

Postby JMPGuitars » Mon 07/01/19 9:15 am

crgfrench wrote:
Mon 07/01/19 9:05 am
Hendrix, Page, Clapton, Beck, Trower, SRV ...they didn't use tone tubby, scumback, weber or WGS speakers. Come to think of it, they didn't use Sozo caps or Mercury Mag iron either. I feel like there is a lot of hype in this field?
There is. And you just listed a ton if it. I'm gonna go add some stickers to my guitar to make it sound better. ;)
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Re: "Detuned" 4x12 and an 18W

Postby colossal » Mon 07/01/19 10:10 am

JMPGuitars wrote:
Sun 06/30/19 5:47 pm
I have a mojotone vertical 2x12 I had custom made. I'm not a fan of their kit layouts (soooo many posts fixing that stuff on here), but I like their cabinets.
Those look real sharp. I see the 2x12 vertical. Bet it sounds fat. Have you tried your EF86 Lite into it as well?
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Re: "Detuned" 4x12 and an 18W

Postby roadshow » Mon 07/01/19 10:13 am

When you say you have only one in the 2x12 do you mean you have an empty hole or are just driving one?

And which hole are you using?
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Re: "Detuned" 4x12 and an 18W

Postby JMPGuitars » Mon 07/01/19 11:56 am

colossal wrote:
Mon 07/01/19 10:10 am
Those look real sharp. I see the 2x12 vertical. Bet it sounds fat. Have you tried your EF86 Lite into it as well?
Everything goes through it. It's connected to the attenuator on my bench for the moment. I do have a cheapo 10" speaker box that will be attached to my bench when I move into my proper office...eventually. Then this cab will sit out with a head like it should.
roadshow wrote:
Mon 07/01/19 10:13 am
When you say you have only one in the 2x12 do you mean you have an empty hole or are just driving one?

And which hole are you using?
Yup, empty hole. It's in the bottom hole to avoid making the cab top heavy. I imagine it would have some affect on the sound switching it, but I never cared enough to A/B them.
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Re: "Detuned" 4x12 and an 18W

Postby colossal » Wed 07/03/19 7:10 pm

20W Greenbacks have arrived, just in time for the holiday weekend.
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