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Assuming you have the bass-bloom issue, how do you run this gear to compensate? Thanks.
Originally Posted by gitman
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07-25-2025 06:16 PM
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Are you referring to vocals only, or, also, jazz guitar? If guitar, what is your signal path, if I may ask. Originally Posted by Alter
I'm guessing here, but I'm thinking that the peak in the 80-150 hz area is at least partly below the range of a lot of vocalists and may add a bit of "warmth" to the vocal sound. I've heard it sound great for vocals. But I'm getting inconsistent results for guitar.
For guitar, what seems to be a spike at around 160 causes E3 to bloom and the first harmonic of E2 to bloom as well. You can dial it out, but not without affecting other frequencies.Last edited by rpjazzguitar; 07-25-2025 at 07:32 PM.
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I have only borrowed the Bose S1 pro for a couple of gigs, but i remember it being pretty neutral. I had a Tonex one setup the way i do when playing through full range speakers, and it was ok. Also tried it with a Boss Gt1000 core, same results. But i do program the digital stuff loud, cause otherwise its a pain. For a much more predictable result, you can use an analog amp sim like the sansamp blonde or something fancier like the two notes revolt or simplifier etc. I will be using the Bose S1 with an HX stomp, digital compromise but extremely portable and powerful rig.
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Why would a spike at 80 Hz cause 160 Hz to "bloom"? Originally Posted by rpjazzguitar
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Thanks for catching that. I meant 160hz, although there is also a spike around 80. I fixed it in the original post. My thinking is that 160hz is around E3 and the first harmonic of E2. Originally Posted by nevershouldhavesoldit
I'm now wondering if the Alto TS408 might be a better choice. I need something for vocals to replace my recently deceased Mackie. Even if it doesn't work for guitar at least it's cheaper.
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The first harmonic is defined as the fundamental frequency itself. So the first harmonic of concert E2 is 82.4 Hz. The second harmonic is one octave above the fundamental. Originally Posted by rpjazzguitar
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Ahh. I thought it was fundamental and then, an octave up, first harmonic. Another thing I had wrong. Live and learn. Originally Posted by nevershouldhavesoldit
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On last night's gig I used the Bose S1 as a monitor. Two mics and guitar into the mixer. Main output to a Fishman mini PA unit and monitor output to the Bose S1, on the floor tilted back towards us. The story is more complicated than that, but that's the core of it.
Singer noticed, as I did, the bass bloom, and commented. I dialed it out, with the bass control on the Bose and some on the mixer, but it took some of the warmth away from the guitar.
FOH sound remained good and I got compliments on what was coming out of the Fishman unit. But, yet again, I was unhappy with the Bose S1.
We've had that gig for three years. We started as an instrumental quartet and added the singer about a year ago, eventually dropping the keyboard. As an instrumental quartet, we each played through our own amp and ran a mic for announcements through the kb amp, which he put on a pole. Simple. Anything wrong with your sound, you knew where to look. And, everybody could hear everything pretty well.
Now, with two vocal mics and trying to get the guitar to work through the PA, I'm impressed with how complicated things get.
Guitar>ME70. Then, one output of the ME70 to a Roland JC55 (which I mostly left off). The other output of the ME70 to a mixer.
The mixer is stereo but we're only running one channel. It has main and monitor outputs. Main goes to FOH (the Fishman unit) and monitor goes to the Bose S1 on the floor facing us. This mixer doesn't have a separate monitor mix unless you sacrifice reverb. We could have kluged it up by using the stereo main outputs and the pan control, but we didn't go there.
So, during the sound check it was all declared fine FOH. There was the bass bloom issue later, which I controlled, but sacrificed some warmth in the guitar.
With this setup, I had a volume control on the guitar, one on the pedalboard, another on the JC55 (mostly unused). Three more on the mixer (not counting the Gain knob), two on the Fishman and one on the Bose. Similar picture for tone control. Circumstances conspired to give us less than enough time to get things set up properly. We ended up with a workable gain structure, somehow.
I claim no expertise in live sound. I'm aware it's a significant discipline. This gig has a tiny bandstand. We had to make choices about where things could be with the only feasible location for the FOH speaker to be in front of the band (where else?), which made it harder for us to hear. Hence the monitor.
First thing to fix, it seems to me, is to get a monitor without the bass bloom issue. Checking on line and talking to a friend who has the Bose S1, the bass issue is not just me. OTOH, it's not everybody.
I haven't been able to find a frequency response graph for the Alto TS408, but I'm going to continue to look.Last edited by rpjazzguitar; 07-26-2025 at 02:52 PM.
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Yes, is it (leakage) relevant to this conversation? I don't know what sgosnell was referencing when he brought up the firehose analogy. Originally Posted by nevershouldhavesoldit
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I didn't bring it up, I just partially objected to it. Look at post 14. He just said water hose, not firehose, but I don't think it matters what the water from the hose is hitting.
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Update.
I'm getting a good sound for vocals with the Bose S1. Not so much for guitar.
I seem to be re-inventing the wheel. That is, going through the process of reaching the well-known conclusion that a powered speaker isn't a guitar amp. I still can't explain how the Bud is good for both voice and guitar -- but I haven't tried it myself. And, a lot of the Bud reviews are based on archtops -- and I play a semi.
However I used the Bose S1, guitar plugged into it, through a mixer, different settings on the mixer, different settings on the Bose - when I turned up the volume I got a lot more bass than I wanted -- and more bass emphasis than I get with my guitar amps (so it isn't just non-linearity in auditory perception, or so it seems to me).
Why do vocals sound better? Maybe because they aren't as low in frequency as a guitar. Lowest note for singing is probably and octave below middle C. The low string of the guitar is the E below that. A basso profundo sings lower than C, but I don't know one.
I had a better outcome with the Mackie SRM350v2. I could run that from the mixer or from the LJ and get a sound I liked. The v3 is, apparently, quite a bit lighter in weight, so I may go in that direction. Heavier than the Bose, but less money and hopefully more functional.
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It's an interesting journey (perhaps more interesting to read about than to actually be doing).
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I ordered an Alto TS408, partly on never's recommendation and partly on reviews, weight, EQ spec and price.
The manual rules out using a passive electronics guitar, so it apparently wants low enough impedance feeding it. From what I gather, less than 1kohm. The Bose S1 adjusts itself to the correct impedance, I think.
The ME70 has 2k from both the rec/phone and the amp outputs. The ME90 has 1k or 24ohm if you use the headphone output (any reason not to do that?). Interesting trend in the ME series output impedance ratings.
I like the ME70 well enough, but it may be time to rethink it if I can get the functions I need and be able to plug into the Alto without yet another device in the signal chain with its own need for power. The Alto has 6 band parametric EQ, which might help.
Or it's another blind alley.
I'll also check to see if the LJ can drive the Alto adequately. The LJ doesn't report an output impedance. It worked okay with the Mackie SRM350 fwiw.
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Did you ever try changing the settings for the subwoofer (making the S1 behave as if a subwoofer is attached to it and therefore not sending the lows to the speakers)?
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The manual “recommends” active pickups - it does not say you can’t use them. Running a passive HB into a mic input often works fine. A minor impedance mismatch is usually inaudible or easily corrected with a slight EQ tweak. Originally Posted by rpjazzguitar
The manual is wrong about using a DI for passive pickups. A true passive DI is designed to accept any pickup’s output and convert it to a mic level signal that can be run into a mixer’s mic input. There are many active interfaces that will drive a line level input, but these are not true DIs. The “direct” in direct box literally means direct to a mic input on a board.
A DI may be necessary for many of these powered speakers - but you may be fine with your guitar directly into it set for mic level input. If your guitar won’t drive it to clean sound at acceptable levels, it only and properly takes a passive DI - you don’t need power for it. The Radial Pro sounds great and is $130, tough as nails, quiet, and easy to use. I’ve played through many and would buy one if I needed a DI. Originally Posted by rpjazzguitar
There’s a $30 Behringer that gets decent reviews, but I’ve never tried one. The $200 Rode is also excellent, but I think the Radial sounds as good. The only DI I’ve ever used that clearly sounds any better is the active $1000 Reddi Box, and it’s not that much better. I’ve compared the Radial to the Reddi on many guitars and gigs because my old club had both, and I wouldn’t spend the extra $870 for it. It’s a tube circuit that makes a guitar sound a tiny bit richer & warmer…..maybe.
Try the guitar straight into a mic input on the Alto first. You may be pleasantly surprised.
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Yes. You can do that with the app. Sound gets very thin. Originally Posted by Freddels
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If I understand the situation, the ME70 puts out -10dbu at 2k ohms output impedance, unbalanced. Originally Posted by nevershouldhavesoldit
The LJ, btw, apparently puts out a balanced signal (I assume that because it's xlr, is that right?). No spec available for the LJ's output impedance. The input impedance for the Alto is 20k for balanced.
Again, if I understand this, which is iffy, -10dbu is near the low end of the voltage range considered line level. And, 2k is marginal for output impedance when going into a 10k input impedance. So, it isn't perfect, but it might be good enough.
This is why the manual recommends active guitar pickups. You're quite right that it didn't say you couldn't use passive pickups, at least not outright, but they recommend against it.
Of course, there's enough gain and EQ available on the Alto that it might work well enough, which would be great.
Thanks for the help thinking this through.
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CONSUMER vs PROFESSIONAL AUDIO LEVELS: -10 dBV vs +4 dBu – Audio University
I think that an issue is that the output of your Boss device is "consumer" line level (-10dbu) and most powered speakers are looking for "professional" line level (+4 dbu which is 12 times higher). The pickup output going to the Alto will be significantly lower than pro line level and possibly lower than the Boss's consumer line level. ISTR having a similar discussion about this in the rec.music.makers.guitar.jazz news group probably 15 years ago. I had good luck with my Alto powered speaker (TS110a) using a Zoom multipedal that had a pretty hot output, enough that I got good volume out of the speaker.
As far as I can tell, there needs to be a gain stage between your equipment and a powered speaker. I wonder if simply adding a transparent boost pedal between the output of your Boss ME70 and the powered speaker would be enough to resolve this. Although perhaps the speaker that you ordered will have enough gain on the input, which would certainly make things much simpler.
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Thanks for that. I remember a similar discussion. I've heard that Alto used as follows: Originally Posted by Cunamara
guitar>AER Compact 60>Presonus Preamp (featuring a 12AX7) > Alto.
A bit of hassle, but easy enough to lift. I have a mixer and the LJ, either of which can be used to boost the signal for proof of concept.
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The mic preamps in some of them will do the job because they have variable input impedance. As long as the impedance mismatch between the pickup’s output and the preamp’s input is minor, it will work well. The old rule of thumb was that input impedance should be at least 10 times higher than source impedance. But even 5 to 1 is almost always fine. Originally Posted by Cunamara
The reason for the ratio is that too low an input impedance will put too much of a load on the source. As impedance drops, it takes more current to maintain the same voltage through the load, and voltage is what drives the preamp stage. If the source (in this case, a pickup) can’t generate enough output through the input resistance to maintain adequate signal for the preamp to multiply, there will not be enough signal strength coming out of the preamp stage to drive the output stage and the speaker.
I don’t own an Alto, but I’ve heard several and they sound great. I just checked, and the Alto TS series has a 20 kOhm unbalanced line input impedance, which would be fine for a humbucker with 5 to 6 kOhm source impedance if the preamp were sensitive enough. But the sensitivity of the line input is too low for a standard output pickup to drive to usable SPL. And the mic input is 1.2 kOhms, which is too low for a high impedance pickup to drive.
As I said in prior posts about this, I use an ART tube preamp for mic ahead of a guitar amp or my own powered speaker (a cheap 8” 150W unit I got from Amazon for $125) when I need a mic on a gig. But if I wanted to run my guitar directly into a powered speaker that lacks an adequate preamp without needing another power line, I’d buy a Radial DI.
Originally Posted by rpjazzguitar
IIRC, the line out from the LJ will drive the line input of the Alto very well. It is not a true mic level DI - I’m pretty sure it’s line level.
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This information is much appreciated. Originally Posted by nevershouldhavesoldit
If I may ask, which stat in the Alto manual tells you about the sensitivity of the preamp? Or, if it doesn't, how do you arrive at that?
My goal is to be able to look at the spec sheets and tell if something is going to work or not.
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The Alto product spec sheet says nothing about the actual sensitivity of the preamp inputs, and neither did I. It does specify the input impedances as "Line: 10 kOhm, balanced, 20 kOhm, unbalanced, Mic: 1.2 kOhm". Originally Posted by rpjazzguitar
I said that "...the sensitivity of the line input is too low for a standard output pickup to drive to usable SPL". 0 dBu in consumer grade audio equipment is reached at 0.775 V input. In equipment built to professional specs, it takes 1.228 V to drive the preamp to +4 dB (the pro reference maximum). Pro equipment is built to handle line level signals up to +10 dB before audible distortion sets in. Passive pickups don't even put out that much voltage into their ideal impedances and will simply not be able to push enough current at the requisite voltage through lower impedance loads than they're designed to use.
A standard humbucker generally puts out about 30 to 40 mV from single string notes and somewhere between 150 and 300 mV for heavily strummed full chords. High output pickups may put out twice that or even more as a peak when a power chord is first struck, dropping off rapidly to below 150 mV. This is nowhere near enough to drive any line level input close to its maximum, even if the input impedance ratio is >10:1
I also said that powered speakers will make enough decent sound with a guitar directly into the mic input if that input is sufficiently sensitive and the impedance of the input is high enough compared to the output impedance of the pickup. An SM57 puts out about 2 mV at 94 dB, so sensitivity is not an issue. Any basic mic preamp is sensitive enough to use a guitar pickup's signal. The problem is that the input impedance of most mic preamps is nowhere near even 5 times the output impedance of a pickup. So most passive pickups can't maintain voltage and generate enough current to drive most mic preamp inputs. There are also EQ differences between mic and instrument inputs on many preamps that have both.
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IME the AER is a better sounding amp than the LJ. I'm still a little baffled why you need all that stuff in the signal chain. I just go straight into my Quilter Cub or Evans JE200, then line out to my EV Evolve 30. If I'm playing in the big band I work with of course I don't need the EV. Originally Posted by rpjazzguitar
I tried the 8" powered speaker route with a LR Baggs Para Acoustic DI and could never get it to sound great. Just acceptable.
You've mentioned in several previous posts that you were happy with your rig into a JBL Array system. Why don't you just get one of those, accept that there is no perfect amplification system for every venue/gig and move on?
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That JBL system weighs about 60 lbs. Originally Posted by SierraTango
As far as the rest of it goes, I play with a pedalboard for a few processed sounds that I use routinely and for the volume pedal, which I always have my foot on.
From there, I'm happy to go straight into a Roland JC55, if that's enough amp for the venue.
Often enough, though, there are also two mics to amplify, so there's some sort of PA. And, that may require a device to match impedances if I'm going to run a guitar through it.
That AER>Presonus>Alto rig sounded great. It was being used by a great player. I've never A/B'ed the LJ with the AER. One thing about that comparison is that the LJ is around $400 and the AER is around $1500.Last edited by rpjazzguitar; 08-03-2025 at 07:05 PM.
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The Radial passive DI box arrived. I'm still waiting for the Alto.
But I did an experiment and I'd appreciate any help with understanding the results.
I ran the output of my pedalboard (2k output impedance, -10dbu) into an A/B box. This is just a DPDT switch.
One output of the A/B box went into the Radial DI (no pad) and then into Channel 1 of the Yamaha MG10XU mixer.
The other output of the A/B box went into Channel 2 of the mixer.
Channels 1 and 2 of the mixer are identical.
So, guitar>ME70>A/B Box
A: DI>Mixer
B: just Mixer
Channel 1, with the DI box in the chain, was a lot quieter. Since the gain of the DI box is listed as -22db, this isn't surprising. It's supposed to take a unbalanced line level signal and make it into a balanced mic level signal. The ME70 puts out consumer line level, -10dbu, if I've got this right, and it's being reduced by 22 db.
After equalizing the volumes using the gain control, as well as I could, the result (played through a Roland KB150 XLR input) was that the DI box chain sounded mellower, or warmer or less harsh, for want of a better descriptor.
I then tried it running the gain control the same way for both, at unity, and adjusting the channel volume controls to match the volumes. There was a smaller difference in sound quality, but the DI still sounded a little better. So, the gain control does a little something to the tone.
I then removed the ME70 from the chain entirely (bearing in mind that it had been feeding both sides equally via the A/B box). The two chains got even closer -- when run with the same gain setting and different channel volume settings (same resulting volume, as close as I could). There was a hint more bass from the non-DI side.
Next, I removed the mixer from the chain. So it was guitar>A/B box>Roland KB150. I plugged both sides into Ch1 which has both an XLR and a 1/4" input. I had to crank the KB150 up to the point where the hiss was audible (even without my hearing aids) in order to get a level of volume I might use in a rehearsal or small gig. Then, switched to the 1/4" line without any movement of the knobs, the thing was blasting and sounding boomy.
The specs for the ME70 and Yamaha mixer suggested the need for the DI box. Perhaps oddly, it seemed to help more with the 2k output impedance of the ME70 than it did with the output of the guitar (passive HB). But these differences were subtle and might have been due to me being unable to match the volumes perfectly.
I'm concerned that the passive DI box might create volume problems although I understand that it's no lower in output than a typical mic.
I guess my question comes down to, what should I expect to hear as improvement due to the DI? Or, how do I understand these results? Would an active DI be better, or did I just prove to myself that I don't need one?
In a few weeks I'll be playing at a camp where I'll have to go through different PA systems I've never used before. Should I plan on using the DI box?
And yes, I know I'll have to recheck all this when the Alto arrives.
Thanks in advance for any help.
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