Double Bass Woods, AI, and Quad Cortex, oh my!

[Don Box]

Context: I'm a doubler, I'm generally a "my bass only louder" person, and have two bass heads that work great but given the runway on Woods and AI units, they'll work until they don't and then it's on to something new. I'm looking to get ahead of that.

I'm about to get a Fuchs, as it seems to be the successor to the Woods, and I'm primarily a Woods person.

The Woods and AI are dual channel, which great for doublers. The Fuchs, like many modern SMPS/Class D heads is single channel.

I've seen that the Felix is popular with doublers, as it has two channels and apparently sounds fantastic.

Tonight, I tried an unorthodox alternative approach, which was to use a Quad Cortex as the preamp (it's two channel BTW), running through the effects returns on both amps, bypassing their preamps.

I did a first pass at tweaking both it and my woods and AI this evening and doing A/B/C testing with both my upright and P bass.

As always, I prefer the Woods over the AI. The AI tone is pretty unique, but not terribly flexible in my experience. The Woods has more top end (which I love) and has much more EQ control, although I generally run it pretty flat.

The thing that surprised me however was how good the Quad Cortex sounded on my upright. I just did some light EQ using the multi-band parametric module, and was able to get close to both the Woods and the AI tones. I was also able to get a tone I liked better than both of them, but until there are guitarists or drummers around, it's all hypothetical.

And naturally, I plan to do captures of both heads while I still own them and they still work. In theory, I'll have digital replicas that will work as long as Neural DSP continues to support the Quad Cortex (which is always a risk given that sector of the industry).

 

[gtirard]

Super interesting, thanks!

Do you hear a noticeable difference between the sound of Quad Cortext into the FX return of Woods and the AI?

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For info, if you are still interested by a modern bass amp with 2 channels, GR Bass makes one with 2 inputs and full EQ section.
They have a good reputation, and claim to have a very transparent sound: the tone of your instrument, louder (it seems to be what you are looking for)

They also have a "Pure" switch on each chanel: it defeats the EQ, useful either if you want no EQ at all, or as a mean to facilitate EQing by quickly comparing the current EQ to a flat reference while turning the knobs…

 

[Don Box]

Thanks for the tip on the GR Bass. Andy Fuchs’ explicit design goal to have a Woods alternative is hard to resist, so it’s my next step. If I wind up not loving them, you’ll see a post to classifieds, at which point I have to resume this distraction, which I’m looking forward to coming to an end.

 

[Don Box]

Super interesting, thanks!

Do you hear a noticeable difference between the sound of Quad Cortext into the FX return of Woods and the AI?

---

For info, if you are still interested by a modern bass amp with 2 channels, GR Bass makes one with 2 inputs and full EQ section.
They have a good reputation, and claim to have a very transparent sound: the tone of your instrument, louder (it seems to be what you are looking for)

They also have a "Pure" switch on each chanel: it defeats the EQ, useful either if you want no EQ at all, or as a mean to facilitate EQing by quickly comparing the current EQ to a flat reference while turning the knobs…

View attachment 6971403

As for the relative differences between the Walter Woods Blue Light (WW), Acoustic Image Focus III (AI), and Quad Cortex.

I’m testing the following permutations all using a ‘61 P bass and Berg HDN112 cabs:

- WW->WW (that is, just the WW with the EQ flat).
- AI->AI (that is, just the AI with the EQ flat).
- WW->AI (send of WW wired to return on the AI).
- AI->WW (send of the AI wired to the return on the WW).
- QC->WW (output of QC wired to the return on the WW).

All of this was with flat EQ. I also spent time with the EQ on all three preamps trying to emulate the sound of both a WW and an AI when run with EQ flat.

I took extensive notes and photos of knob settings, but here’s the TL;DR of what I found:

1. The AI power amp has a much lower frequency response than the AI preamp does. That is, the “AI sound” seems to come at least as much from the power amp/post return section, which I found surprising. The AI preamp through the Woods power amp actually sounded fairly usable for electric. This btw is partly why the AI can’t come close to the WW sound.
2. The Woods EQ can emulate an AI a lot more than an AI can emulate the Woods - a lot of this is due to point #1. I concluded that the only way I’d use the AI on a pure electric gig would be if I wanted a dark, wooly, old school sound. I’d intuited this years ago, but it was good to really focus on it (and understand why).
3. The noise floor is much higher on the AI. Basically, turn it on with the master at 0 and you hear hiss. Not so with the Woods, although cranking the Woods up definitely brings some noise with it.
4. The Woods send/receive is out of phase with the send/receive on the AI. Basically, if the same signal goes to both power sections, say goodbye to any bass frequencies. Strangely, the DI out of the Woods is fine.
5. The sensitivity of the return on the AI is much higher than that of the Woods. I had to crank the Post Gain on the Woods higher than I’d have liked, but it was more than usable.
6. The Quad Cortex can emulate the Woods sound quite well using the parametric EQ + a little compression. The Woods preamp has a really crisp top end, but it’s definitely has some minor coloration (a bump around 100hz and 6khz+).

I have a few more tests to run, primarily on trying to characterize frequency curves of both the Woods and AI preamps - sadly using just my ears and a parametric EQ, so very unscientific and subjective.

 

[Don Box]

Tonight was Quad Cortex night.

I’ve did neural captures of the Acoustic Image preamp running flat EQ.

I did the same for my Woods, plus a bunch of permutations of tone control settings. I’m also beginning to find the best way to emulate WW tone controls using the native EQs in the Quad Cortex, which is honestly much more practical.

Unrelated, I purchased the IRs for all of the Berg NXT/NXV cabinets for ~$45. The HDN series isn’t covered, but honestly, these are the best sounding bass cabinet IRs I’ve heard so far.

So basically, I’ve got my rig’s signal chain captured/emultated. I’ll stitch together the pieces into meaningful presets and start using it IRL.

 

[Don Box]

More updates.

To my ear, the capture of the Woods is more than good enough that I’ve stopped worrying about captures and am focused on integrating it into my overall digital and physical signal chain, which makes me happy.

I really only care about two amp sounds: Woods and SVT (which is why a pair of Fuchs will be here in a couple of weeks).

I’m looking forward to having a Fuchs tube model, but for now I’m stuck in digital only land.

After spending time in capture land, I did the experiment with SVT sounds in the quad cortex.

I’d been using the *modeled* SVT, which sounds really good and has all of the controls I remember from the SVT I owned as a late teenager.

There are also eight SVT captures that come with the unit, so I tried them. While there’s no ultra-hi switch, it sounds exactly like I remember.

 

[Don Box]

Just tying up threads that I opened a while back.

I love my FBS 700 and am happy leaving my Woods at home as a sentimental nod to four decades of my lifel

I also have been using my Quad Cortex a lot, especially when I know I have to use some random amp at a venue or studio.

 

[Ric Vice]

Even though I don’t play my Walter Woods Electroacoustic Ultra on gigs anymore it’s hard to dispute how that preamp can EQ the worst rooms to get a beautiful, clear, warm, musical tone. In addition to that, it’s got more useable headroom than any amplifier I currently own with the possible exception of the Monique M700, but my sense is if I ran the Woods along side the Monique it would definitely keep up. Just my take.