donkelley

It's to improve the looper! FINALLY!

good ideas! Actually, no I can't do that. I can't even figure out why the wah pedal changed the sound source! I'm sort of new to this level of patch editing. I will absolutely keep trying, though. I created this on the device, not in the computer editor, so maybe it'll be easier once I see it in the computer version. I'm very happy that it works for you!

Hey! Just saw this thread and thought I'd take a stab at creating something like that EFX pedal where you hit the button while holding a chord and it records the chord, hit it again and you can play over top as much as you want. EHX Freeze I think it's called. With a couple limitations of what the footswitches can do, it's not quite the same (it takes 2 buttons), I think I managed to do a pretty decent job. It's not like OMG it's the same effect, but it's close enough to be useful! I attached the patch to this post. What I did is I took one of my favorite stock patches (Flood in Texas), which works great with my RG in single coil mode (a high output strat, basically), and built a freeze effect into it. There's one switch that turns on or off a delay effect and also sets they delay effect's feedback to 100% when on and 0% when off... so this button is the effect on/off and freeze reset all in one ... to clear the freeze sound that's playing you hit it to turn the effect block off. This also clears the feedback delay buffer after one last playthrough at 0% feedback, so next time you turn it on there's no sound until you enable the freeze thing. Otherwise, turning it on again just started playing back the previously frozen sound again... there was no way to reset it. This also gives the extra feature of letting you supplement the current freeze with more tones... get a freeze going, set it to play over top, play a super amazing harmony up high on the neck or something that will go well with your already frozen chord, turn on path 2 for a second or two and then turn it off again, and now your freeze is the combination of the two chords, and you're back to playing over top. If you want a way to record a new, different, freeze chord to replace the currently playing one without turning the button 1 effect off and on again, try this: -- play a new chord (different key or whatever now for next part of song) with button 2 turned off while the freeze is still playing, then quickly hit button 1 button 1 button 2, wait a second or two then hit button 2 again. You've just wiped the old freeze effect and turned it off, turned the freeze effect on again, turned on record freeze for the chord you are already playing, waited a couple seconds for it to fill in the freeze effect nicely, then turned off the freeze record setting so you can play over top. It's a foot dance, but doable. From what I've seen of the ACTUAL freeze pedal, this is honestly not that much harder to use. There's a second switch that toggles between 2 paths (using volume blocks with preset state toggles). I currently am using it in an on/off state, but possibly it could be setup as a momentary thing... Not sure that's important though as this works really well. So when this 2nd button is OFF, it takes path 2, which bypasses the "freeze" effect path. So this is for normal playing even when the freeze effect is turned on, and it prevents anything going INTO the freeze effect to be added to the freeze loop. Just play normally, and normal sounds come out - no freeze. When 2nd button is ON (assuming the freeze effect is turned on), signal is routed into the freeze effect path (there are I think 3 effects in this section - a soft attack thing, a digital delay with roughly half second loop and 100% feedback when enabled, and an ethereal kind of reverb effect). So to use it, you turn on 1st button to enable the effect, then (ideally) play a chord and right after attack turn on the second button for like a second or two then off again, and voila, freeze effect! You could just not play until both buttons are on then strum a chord and then turn off the 2nd button, but it'll have a lot of attack in it. The first effect in the block of 3 could, potentially, help take care of that, but it's just easier and way better sounding to strum right before you hit the 2nd button. I'd say 1st button is effect enable and disable/reset. 2nd button is record enable and disable for what gets frozen. I then put some other nice delays/reverbs in the other path and have lots of fun playing various styles over top of that freeze. To me it sounds just like the demos of the EFX freeze pedal. Update: I just attached the patch! Hope it's fun for people! The buttons are 10 (2c) and 11 (2d): Button row 2 C and 2 D are buttons 1 and 2 of the freeze effect. 1B is just a delay for playing normal guitar, 1C is a reverb for playing normal guitar, and bottom row 2B is a really atmospheric reverb, again just for playing normal guitar. bottom row 2C enabled/disables/resets freeze effect, and bottom row 2D enables/disables recording the freeze part (bottom row 2C must be turned on for this effect to work properly though). There's a wah too you can enable by stomping on the pedal. The freeze just sounds like a sort of mystical version of the chord you played, as though held on an organ or something. I purposely kept the freeze level lower than regular playing so you can play over top of it (the output of the delay stage). Strat+Hold DBK.hlx

I thought it meant he was second guessing everything he'd heard in the places you mentioned because someone from line6 just posted in this thread and he feels there is room for interpretation... and maybe it won't be in 3.0 but in a future FW release that they have finally got Poly Pitch Shift working, because of the extra design time and effort required for the new algos. But I guess sarcasm and assuming he's being dumb or lazy are your natural reactions.

Poly is what is exciting to me. Whether shift or synth, although I would imagine the solution for tracking one could help the other with the similar poly tracking issue too, so possibly both could become poly trackers. But mostly, a poly shift removes my need for yet another of my external pedals. That's a win right away! Based on history, you'd think there will be another amp model or two as well, just seems like they try to do that when possible in an update. And... just for my friend DataCommando... I'm going to be looking for any type of looper improvement. I know DC is excited about such things.... :-)

I'm sorry folks - this guy decided after reading one post of mine on loopers (which was a supportive reply to the OP's complaint about the looper), that I was apparently incapable of knowing what I was talking about, and couldn't possibly understand how a company like Line6 creates their products or the complexities of adding features into firmware. There was never any attempt to be polite, or possible acknowledge that I might actually have any experience of value in the industry. Note: I'm a mature senior software engineer and have been working in various types of software for most of my life (middle aged now), while most of my training is in both music and in audio engineering. I'll leave it up to others here to decide if he's an insulting arrogant person to me, after what he just posted in this thread that was off topic completely, just to attack me. So again, I apologize that he decided I'm an idiot, and not actually a really nice guy with a lot of knowledge on certain parts of the industry who's just trying to help contribute here to problem solving. I'm telling ya - it's enough to drive me away from Line6 products after more than a decade of dedicated use.

Fair enough :-) As I noted in my later post, I was mistaken in my assumptions about the helix headphone amp - or at least in the intent behind it's design. It's unfortunate that it has a relatively high output impedance, because if it was a lower output impedance then it would be quite stable with nearly all professional headphones you can buy, most of which are lower than 60 ohms impedance (as my amazon search for "studio headphones" showed, just randomly... I wasn't looking for low impedance phones). But I did completely mistake it's ability to drive high impedance headphones - it's odd that my akg high impedance phones don't behave well with it, but it seems high impedance phones do for others on the helix, and that the designers claim it was made for high impedance phones, which does jive with the output impedance, after I did the math. So I based my assumption on an actual test wtih actual high impedance phones, but my test must have failed in some way. Things happen - and I got called out on it by someone else (rather emotionally LoL). Done deal. It is, though, truly odd that the helix targets high impedance BETTER than most studio/professional/consumer phones. It's not like most pro or studio phones are high impedance. And of course, it's not like it won't work great with many low impedance phones - just that it won't support them as ideally, due to poor damping, as it could with lower output impedance. Just a choice they made - obviously it was a trade off, and they went the way they went. Fair enough! I was, though, accurately summarizing the majority of differences between how amplifiers work with loads. There are complexities related to how current and voltage work together to drive the voice coils in headphones to create the magnetic field. Both voltage and current are part of every design. It's not something that we can get into in this discussion, and doesn't help anyone. Headphones don't supply enough data to calculate the way everything in the circuit will work, and the basic summary is you need more power to drive higher impedance phones. Current/voltage are both part of that calculation, but it's not a simple calculation that we can predict since there is mechanical reaction in the headphones for physical damping that benefits differently from various power conditions. So, imho, it was sort of a surprising reaction. I, too, am just trying to contribute in my particular area of knowledge - which happens to be engineering, audio electronics, and pro audio (and music of course, as we're all musicians here!). But it's ok, you clearly are very dedicated to figuring this out, and that's great - more power to you. I was just trying to point out that nearly all headphones are lower than roughly 60 ohms impedance, and nearly all headphones amps are made to drive those. It turns out the helix actually isn't designed to - it apparently targets ONLY higher impedance phones (based on the output impedance and what I read in some quotes), and provides less than ideal damping for what I consider "normal" headphones (normal meaning nearly all headphones fit into this impedance range of less than 60ish ohms), which could result in some changes in frequency response compared to running those same headphones on another headphone amp. It's pretty simple - and it's correct information. It's just electronics facts, summarized in a useful way, without getting into guessing games about specifications that aren't listed. Anything further requires measuring very specific details of the helix while connected to each specific pair of headphones while supplying a signal generator source sweeping the audible range, and so on... which, as I said, is way beyond this topic. I do hope it works out for you and look forward to your findings! Cheers - interesting thread!

Wow. Ok. I'll go back to engineering. Cheers Interesting forum you folks have here. C'ya

Good info! Thanks! With a damping factor so poor for most of the headphones you can buy (IE: anything less than 120 ohms), it didn't seem likely to me that was a high priority, but I made an assumption and was wrong. My apologies for the misinformation assumption, and to line6. At least it has a lot of power to drive lots of types of headphones. Even as some of them won't sound as good as they do on many other modern headphone outputs (due to insufficient damping to have predictable results with most headphones), others will sound better on the helix than they do elsewhere (due to sufficient power compared to weaker headphone amps). Sorry for my assumption, again! :-) Oh, by the way, this claim is vague and could be misinterpreted in electronics: " Low impedance headphones distort way faster, fatigue your ears, and at a high enough volume, can damage your hearing." The headphone amp simply reaches it's maximum output power more easily with lower headphone impedance. The headphones don't distort way faster unless they are overdriven, which isn't related to impedance but to output power and controlling the volume knob properly. That output power is no less than it is with high impedance headphones, and clipping is not going to happen at lower volume or lower output power. It's just that it takes less preamp gain driving the headphone amp to reach the limit with a smaller load in the circuit, and therefore the volume (preamp gain) knob should be kept lower. The headphones themselves will not be any quieter if they are low impedance or high impedance, but you should never drive an amp into clipping for this purpose, so just expect it to require less volume to reach the highest output that the circuit can work at with lower impedance phones than high impedance phones. If any low impedance headphones are less loud and clear at the headphone amp's highest clean output before clipping (whatever the arbitrary volume knob setting is to accomplish that goal), then that is purely a side effect of the sensitivity of the headphones, not a side effect of the impedance. Same could happen with high impedance headphones - sensitivity has no relation to impedance. Sensitivity is measured in relation to the power the headphones are driven with so there is consistency. In this thread I presented my own misinformation in assuming things about the priority of the headphone amp in the helix - I take that back, as it was incorrect! :-) However, the misinformation about how headphones and amplifiers work is something factual in engineering, and I hope my repeated attempts to clarify facts about how it all works is helpful. Oh, and OP - interesting and cool that the helix has power to drive high impedance phones! Like I said a couple of times - I'm interested in your findings about which phones turn out to soudn best for you, as I'd like to try them too. :-)

Fair enough. I'm well aware that an 11 ohm output impedance can cause poor damping. Shows that the headphone output wasn't a super high priority for line6... which is completely logical. It's not supposed to be a high end headphone amp, and it's not designed specifically to target little portable headphones either. But if you look around, you'll find most headphones are "low impedance"... whether studio, home, or portable, outside of the beyerdynamic world. Pro headphones. They all work just fine with the helix, I'm certain, and as with any low impedance load on an amplifier, can cause the amplifier to reach it's limits sooner, but also get louder in the process. It's a little unfortunate that they let the output impedance be a bit on the high side, but it's not like they're trying to win audiophile headphone amp awards. It's guitar we're listening to here, not an orchestra or full band (most often, at least). Just to give a quick idea of the some of the great headphones you can buy, without searching for low impedance headphones (just searching for good headphones from big name manufacturers that would be worth testing to see if they sound good from the helix), I came across a bunch here, and these are all, completely by fluke, low impedance. I am aware that sennheiser and a couple other builders make high impedance models also, but those didn't come up in my search for professional headphones online. Sennheiser HD 599 - 50 Ohms ($200 high end headphones). Beyerdynamic DT 990 Pro - 80 Ohms (insignificantly higher than the low impedance range I quoted) - these are $200 pro studio headphones. Sony MDR-7506, and 7509 - roughly 60 ohms, 7509 is higher end and has a different 5cm driver (7506 has a 4cm driver)... studio staples Sennheiser HD280 pro - 64 ohms (another studio staple) Sennheiser HD569 - high end full size over ear phones for portable use, with inline mic - 23 ohms (naturally). Shure SRH440 pro - 44 Ohms. Their highest impedance headphones are 65 Ohms, for "studio mastering". KRK 8400 - 36 Ohms. Philips X2HR - 30 Ohms. LoL ok I want to stop now. Some interesting models to try out. I suspect they all soudn radically different from each other. Hope this is helpful info! And if you do find a pair of high impedance phones that sound really good with the helix, I'd love to find out which models specifically so I can try them out too sometime! But, honestly, you probably shouldn't just dismiss everything I told you - it's all pretty interesting history about headphone impedance and how they are driven. Honestly - high impedance phones are such an ancient design, they're from way back when tube amps were in everyone's living room stereo cabinets. These days, they are something of an anomaly, and there is a market of dedicated headphone amplifiers, stand alone AC powered semi-esoteric things, built specifically to drive high impedance phones. When you have the right amp, they can sound glorious! Without a truly great, and very powerful, headphone amp... they sound kind of meh, from my experience. Very interesting thread! QUESTION, though: To quote you above: "Low impedance headphones are 'extremely solid device' for most modern portable battery-operated devices, which have very low (<<12 ohm) output impedances. Helix, for whatever reason they chose, does not fall into that category. " But earlier, this was posted: " The output impedance of Helix Floor is 12 ohms. " So I'm not sure which it is. 12 ohms is extremely close to << 12 ohms. Yes, I agree, there are headphone amps in portable devices that are lower than 12 ohms, and lower is more ideal (to a certain degree) for working with low impedance phones. But 12 ohms output impedance? That isn't a problem for standard (IE: not high impedance) headphones, most of which present between about 30 and 60 ohms impedance (based on my list above). I just googled - iphone 6, for example, had output impedance of just under 6 ohms to nearly 7 ohms. That's pretty typical, it seems, for little battery powered devices. Just backing up your points about these devices :-) I'm trying to find headphone output impedance of popular home stereo amplifiers.... it's a spec that isn't published very often! Would be interesting to know, though :-)

I suggested less than 60 ohms because, for headphones,, anything less than roughly 50 or 60 ohms is "normal"... IE, "Low impedance". Driving 60ohm or less headphones for not only the helix, but any device, is extremely solid advice. You will be lucky to be able to drive higher impedance headphones with anything other than a vintage solid state stereo speaker amp that uses the same output amp to drive headphones (with resistors in place to lower output), or a dedicated, specialized, rather expensive headphone amp that is built to deliver much higher output levels than standard for, well, standard headphones (which are, as noted, anything lower than roughly 60 ohms). There are some unique headphones in the world. Most manufacturers, such as AKG, do NOT alter the tone of the headphones between the various impedances. They sound the same, within the same model.. or if there are differences, they are very very subtle. Beyer has one that is 600 ohms, and it sounds different from the lower impedance versions because it uses far far more coil windings but with finer wire. But most high impedance versions don't sound any different simply because they are high impedance. The impedance is an electrical factor that is intentionally met in the design, as is the tonal characteristic. With tons of windings at a very small diameter of wire, they could have reached a lower impedance. They chose that design because they can... because some home stereo dedicated amps (of higher quality) can drive 600 ohm phones just fine. It's not super practical though, and nearly all gear does not drive 600 ohm phones to a particularly loud level without the amp clipping very audibly. The helix output impedance is 11 ohms? That's pretty normal. The output impedance of the headphone amp is typically several times LOWER than the standard headphone impedance it is designed to drive, but it is not indicative of the headphone impedance it must drive to work well. An 11 ohm output impedance does NOT mean you should be trying to find 11 ohm headphones (which I suspect don't exist). It means it works like any normal headphone amp and will run standard low impedance headphones, and it doesn't hurt to try high impedance phones but I'd not expect great performance. My helix LT can't drive my AKG 600 ohm phones very well, just for example. They sound fine, but very quiet, and mid heavy as those phones always sound. The stereos I grew up with in the 70s and 80s just used the resistors in series with speaker output method for headphones, typically, and sounded fine with anything, low or high impedance. Then I got better stereos with dedicated headphone amps and suddenly the high impedance phones didn't sound as good. Ironic, isn't it? Note: the site you mentioned, and most others, ONLY seem to talk about beyer headphones having different tone for the high impedance model. They use them as some kind of example, because the model of phones exists in different impedances, and sounds different. They sound different because the 600 ohm version is their high end one. AKG 240s come in different impedances, yet they aren't referenced, even though they were a standard long long before beyer (and I am NOT saying they are as good - I typically would take beyerdynamic phones over most others, if price was no object). This difference in tone between impedances is NOT true of AKG or some other major headphone manufacturers. There ARE differences in tone between other changes in the 240 series (there are dramatic changes in how they are made between the "sextet", monitor, studio, DF and so on). But 240s and 240m sound virtually the same, despite the s being 55 ohms, and the m being 600 ohms. The beyer 770 example is a unique thing without any standard, and only is that way because of how beyer designed them. There is not standard correlation between impedance and tone. Folks complain about headphones on the helix because you can hear distortion fizz with headphones. This is quite normal. If you play through a hifi speaker set or certain studio monitors, you will hear fizz if you are close to the tweeter also. Same reason. Revealing/accurate high frequency driver close to your ears, or aimed directly at your ears at the very least (on axis, not angled away, since high frequencies are super directional). It takes equing to get helix to sound great with phones or with revealing speakers. Anyhow - I hope my information is helpful in some way. At the very least it's another opinion from another experienced person who has dealt with recording engineering and speaker design/building a lot over several decades... and unlike some of the websites being referenced, I am actually explaining facts about headphones other than one specific, and unique, example (beyer 770, for example). Cheers! Hope you solve your headphone problem somehow, whether it's using trial and error, research based on web facts, or folks randomly on the forum like me! LoL :-) Best of luck!

Better yet, include all but the second pedal part in a fw update for all helix models! :-) But yes, if not, then helix 2 feature request makes sense.

Well, distortion is from clipping the amp - IE, it's not powerful enough to get loud, struggles with the impedance. That isn't frequency response. Bass? Bass comes from power, which clips first when you run out of power. Hifi folks might choose high impedance phones to tame harshness... but that isn't a crowd that actively uses science or electronics in the most efficient way to accomplish their goals....... Anyhow - I personally wouldn't advise anyone to choose a higher impedance headphone to alter the eq of the tone. You'll mostly just get a much quieter level, and it will showcase any deficiencies in the headphone amp of whatever is driving it. There are other factors also, besides just impedance to take into consideration. Different high impedance headphones may exhibit other different electrical characteristics that make them easier or more difficult to drive, other than just needing more power to handle the vastly higher impedance. There's an amazing pair of headphones by, if I remember correctly, Beyerdynamic (could be remembering the wrong pair here), that is exceptionally hard to drive, needing more than just extra power to sound right. anyhow - certainly ANY different pair of headphones will sound different from what you have, as long as you avoid akg 240 series. I would still go for normal headphone impedance (roughly 56 ohms or less), so you're not giving teh headphone amp a difficult load, and so it's not excessively quiet. Cheers

oh yea, and I wanted to point out - high impedance phones are simply harder to drive... IE: quieter. Tone doesn't improve, nothing darkens or brightens necessarily due to the impedance mismatch. It's not like passive instruments and the effects of impedance, or simple stomp boxes. 50ish or less impedance headphones should normally be used unless you want to daisy chain them in a studio for multiple headphones on one headphone amp, all in parallel (which is what akg 240monitors were designed for... with 600 ohm impedance... but those are a specialty version, not what you are running).

That might be good, like I said. At least you can use it! If a digital encoder wears out, it'll get jumpy - turn it a bit one way or the other and it'll jump to some random value, often in the opposite direction. If you are able to control it - be thankful. I'm very curious though why it's backwards!

If you move it very slowly does it still work backwards? If you wiggle it clockwise and counter clockwise, does it behave consistently? If it changes sometimes, and sometimes goes up, not down, or it jumps around in the values, then the control might need to be replaced. If it's consistent, and you can slow it down to accurately get the correct value you want, just always turning it backwards.... then at least it is useful still! Maybe it was replaced and wired wrong? Who knows....

Just FWIW, For years I used preamp distortion only on guitar, never power amp drive because I didn't have useful tube power amp stages. Then when I did go all tube for guitar, I was at home so never could get loud enough to not deafen myself before power stage would start to clip. When I finally rehearsed with my band with my tube amp, I cranked the master and opened it up - and loved it, until I actually tried to control it with my gain staging etc, and to go clean. Then I heard it miked up - and didn't love the tone any more with power amp clipping than without it, and in fact liked the preamp clipping more since I could filter the top end of it with the treble control in the tone stack. So, for me... I just don't particularly love dealing with power amp clipping. It can sound great, but it's so hard to manage in a recording situation like this that I understand why it might sound like that to you with headphones (assuming you are getting power amp distortion). It's just kind of fuzzy and brittle compared to preamp or pedal overdrive tones. So maybe that's part of it. 240 headphones are a speck middy, also..... and can slightly emphasize presence area, which can sound fizzy. Great phones, but not neutral.

Of course! The world of mac users is very different than pc users, typically. I'm both of those folks, by the way... always have been (and I'm a software engineer). Apple does control things in the apple world. They define what is ok to distribute for their OS, and they have very strict processes for getting applications approved. So your point, while correct, isn't contradicting anything I said. Windows has always had far longer legacy support (both for hardware and applications), and it probably will continue do to so. I never suggested or said Apple is pushing innovation with this particular design decision. But there certainly are very good reasons to stop support for legacy features in any operating system, and this is what they chose. It's up to them, and I would imagine it will have a lot of side effects for those who use older apps on Mac (as I do sometimes, although my Mac is too old/limited to run Catalina.... I use my PCs for my job and most of my music work currently). Absolutely Line6 and any other company who no longer releases new versions of unsupported apps will not be making 64 bit builds just for Apple. But moving foward, there are pretty easy ways to ensure your applications run under catalina (if 64bit is the main problem, of course), so all current software should end up just fine, either now or in the next update, assuming they are registered Apple developers. By the way - all registered Apple developers were warned in 2018 that 32bit app support would be ending with Catalina. So anyone that wanted to support it had plenty of time to do so... and I'm sure legacy apps would be on the chopping block.

I know this is an old post I'm replying to, but that statement seems unlikely. I believe the issue is that Catalina no longer supports 32bit software, correct? That's not an issue, it's a design decision. There's nothing to fix in the OS related to this change. It just shows that finally the world is moving past legacy 32bit software officially, and it's time for developers to build everything as 64bit applications. Hence, if the product is still supported by line6, it must have a 64bit version. If, in fact, the problem is related to 64bit requirement, not something else (if there is a problem at all from the OP's question.... it's unclear to me if there actually is any trouble with current line6 apps on catalina).

Yea, they really need to update that information. Yours isn't the first case I've seen in this forum recently where upgrading to 2.92 from any version, which line6 claims is just fine to do, doesn't work.

Can you contact fullcompass directly to ask for a special order to be placed? Or, I mean... this might sound dumb, but OTHER audio hardware companies out there actually are good about supplying replacement pots to customers to replace themselves. I have an affordable novation synth/midi keyboard/control surface that I love, and use extensively. Several of the sliding pots for settings wore out over time (From stifness, etc). This is a rather old, obsolete model. I bought it used, on craigslist like 10 years ago or more. I emailed their support asking if I could order some of those sliders from them please, and they replied, from England (I'm in Canada) and asked for my mailing address.... and sent them out FOR FREE. Exactly what I asked for, the number of them I asked for too. now THAT is customer support. Line6 ought to have more of these parts available from their Chinese manufacturer... and for a customer who owns their product, they ought to be willing to send it to you, specially with covid-19 restrictions.

Klon is, imho, sort of suited to different things than the tube screamer. Good choice! And your conclusions make a lot of sense about the "why".

In canada (not sure if it's canada only or USA?) we have mouser electronics, for example. I have no idea if they have your part, but it's another company to check. So there definitely are other suppliers. Look around, check stock in each one, maybe even call them on the phone if their website doesn't show stock or can't find the ideal item. There could be another one that fits the fill, same electrically and physically, different manufacturer? Maybe?

Yea, don't crank the amp. They have unity gain markings now, or at least some markings that can get you into that ballpark. However the idea everyone agrees on here, no matter how it's described, is to set the powered speaker (IE: power amp) level at it's best setting, and then control volume from the helix. There are issues with this concept, related to playing live. How do you keep the helix volume exactly the same as you go through the night? So many of us will want to nudge that up gradually... and that can wreak havoc on the soundman who's basing his input level on your helix output level. So keep watch on that, or mark it with a dot of some kind. I think also the helix has an option for fixed level output. As an engineer, that seems logical to me, but it certainly adds practical drawbacks to this whole thing. Also, the helix noise mention seems pretty unlikely to be a problem. The noise from the helix is far lower than the noise from most normal guitar amps, even if you turn it way down and crank a powered speaker way up to get your signal (Which would be extreme, impractical, and pointless.). So just set your powered speaker level, 12 noon someone says, but I say look at your speaker level control and find unity gain on it (I would imagine different manufacturers set unity at different parts of the rotation, but noon is a very safe easy way to start).

Speaker size, assuming they're well designed, doesn't really impact tone much, unless you get into really small monitors. woofers that are 4" or 5" may not get down to the lowest notes you play, particularly if you play any bass or low drop tunings. It would still sound good, but you'd lose some of the fundamental low end. That isn't the point of the monitors - they should be pretty accurate and reach all frequencies as well as possible, and let your virtual cabs in the helix do the tone shaping for you. So, that being said, you want speakers who's frequency response charts show they are pretty neutral and get right down to yer typical 50 or 60 Hz solidly, which is plenty for all guitar work. The speaker size honestly doesn't matter much, but the smaller the speaker, the quieter it'll be, and the more distorted it'll get when you try to get it to play low notes loudly. And some speakers are simply too small to do it, so it'll sound like junk down low AND crap out. But it really depends how loud you want to play at home. a pair of powered monitors (or just good speakers and a stereo amp), with 6" woofers and 1" tweeters, ported speakers that are listed as getting down to roughly 65 Hz.... if they ACTUALLY do that, they will probably sound great with the helix. But don't play too loudly cuz they likely can't handle it. 8" speakers generally can have much higher output, and often get lower, than 6" woofers. 10" moreso. 12" even moreso. These aren't guitar speakers we're talking about, they're hifi speakers (whether home stereo speakers or studio monitors, same concept here), and the cone can be made to get you down low and sound great, but the lower it gets, the more limited it's output level will be, and the lower it's sensitivity will be. Also, likely, the less power handling it will have. So it really is up to you. Small room (Bedroom sized)? A decent stereo system will probably sound amazing. Playing with others or really want to wail loudly like with your real amp? those speakers likely won't last, or can't cut it in the first place. Tweeters wear out fast or simply blow with too much signal (combination of enough power and enough consistent signal to the tweeter). And woofers we already talked about. Behringer studio montiors (2030a, 2031, if I recall correctly) sound REALLY GOOD and are affordable and will get you there, but don't ever take them out of your home or studio. They are not for live use, not even for rehearsal If you ever want to take your speakers out of the house, I'd look at something targetted to portability. Hope that's all helpful info. I'm trying to explain WHY folk say things like "get at least a 6" woofer" or whatever. But always keep in mind, it depends on how small your room is, how close you'll be to the speakers, and how loud you will play.