NGD-Bose Pro8

[meb]

I just picked up a Bose Pro8 a couple of days ago. I am mostly solo
acoustic guitar/vocals, but also play in a couple of duos. Overall, I am
pretty pleased with the sound. It has a slightly darker sound than my
L1m2, but can be EQ'ed to a very similar 'Bose' sound. You can really
appreciate the room-filling dispersion as opposed to the more direct
focus of my K8.2. Both are nice with great tones...just a different
perspective. I have a gig Wednesday in a room where I normally
use my L1m2...I will report on the unit's power capabilities after that.

My testing was done mostly with a Mackie Onyx8 mixer via TRS to
Input 1 on 'off'. Connection via XLR was too hot.

The downsides....I was aware that the base weighed 31 lbs, but it is
more effort to haul around that I thought. At least I don't have to
raise it on a pole like the K8.2.

I had trouble getting the spacer array to connect at first. You really have to
push it hard and adjust it to get a good connection. I had the same
problem with the old JBL Eon One array.

There is not enough gain even with a mixer to use input 3 TRS as
recommended in the manual.

Overall, I think the sound will be fine...more use will help determine
power capabilities and my ergonomic concerns.
.

[Cuki79]

Originally Posted by meb

There is not enough gain even with a mixer to use input 3 TRS as
recommended in the manual.

what mixer do you use?

For once, Bose published the figures


The mic inputs 1&2 can serve as reference. They provide upt o +45dB gain bringing the signal up to +75dB.
Since the max output will be eventually the same, one can deduce TRS 1&2 provide 15dB less gain.
The same pattern can be applied to input 3 and we find Bose expects

* Inst level to be around 15dB hotter than mic (CH1&2 jacks)
* Pro line level to be around 35dB hotter than mic (Ch3 TRS)
* Consumer line level to be around 25dB hotter than mic (Ch3 3.5mm)


If find this table on the internet


maybe it helps

[jseth]

Hi, Mike... I'll be interested to read your findings after playing that gig... especially with your extensive Bose experience via the L1 Model II, and the L1 Compact (and the S1?); good foundation for a decent comparison, I'd say.

Although I'm curious about the newer offerings with these "Pro" systems, it sounds like Bose has taken them into the "deal-breaker" area with the weight of the base/bass units; I know that my Model II has 4 pieces to carry, but at least none are heavier than 24#s. That's about the limit that this old man wants to schlep around!

Is there a reason that you don't use the internal mixer capabilities of the Pro 8? Also, why not run your mixer into the channel 3 "line level" ?

Looking forward to hearing what you think of the new Pro 8...

[meb]

Thanks Cuki....my mixer is the new Onyx8 from Mackie.

Hello jseth, yes I will put it thru the paces. I still have the L1m2 and S1.
The L1C is long gone....too much feedback at too low a volume level.
btw, the S1 had similar tonality within its limited frequency range vs
the Pro8, but all the overtones and fullness were missing by comparison.
I very seldom use it for performances. I look forward to my Wednesday test.

I agree with you about the weight issue. I would have bought a Pro8
long ago if it were lighter. I want to make sure I can handle it before I
commit to keeping it. I also consider the weight on the Pro16, Pro32,
Evolve series, etc to be a deal-breaker. I do occasionally hoist a
28 lb K8.2 on a speaker pole...but not much fun.

With the input #3 knob at noon, there is only a whisper of sound when I
plug a 1/4" trs cable into it; so I just gave up on it for now. I think that
Cuki is saying that #3 expects a hotter signal than inputs 1 & 2.
Cuki, is that correct? Your level of knowledge is way ahead of mine. :-)
...and I am not sure how to interpret all the specs.
Is there a way to send a hotter signal from the onyx8 to input 3?
The onyx8 trs output is 6db lower than xlr outputs if that is something
to consider.

Thanks!

[MarkF_48]

Hey Michael, I'm pretty sure an XLR to 1/4" TRS cable from the mixer output to the Bose 3 input would give you more than ear splitting volume, but if you don't have that type cable kicking around handy, please try a 1/4" TS to 1/4" TS cable such as just a regular instrument cable. I have a suspicion about why the volume would be so low and a TS to TS cable may confirm that suspicion.

[meb]

Thanks Mark_F48 you were correct.
From Onyx8 mixer to Pro8:
TS to TS on Ch3 added some volume.
XLR to TRS on CH3 added even more volume and to a 'semi-usable' level.
Neither put out as much volume as TRS/TRS to Ch1.

Unless I am desperate for an additional input, I assume I should just
use input Ch1 when using a mixer. Besides it seemed to sound a little
better also to my ear.
..ch1 input impedance is 2 Mohms trs vs 200K Ohms ch 3
per the Cuki79 provided specs.

[Cuki79]

If you read the Onyx manual, the schematic shows indeed that the Main outputs are unbalanced. If you use a TRS jack, the ring & the sleeves are both connected to ground. So using TRS or TS cables between the Onyx and Bose won't change anything.

Mackie is indeed "honest" and warn the user than only the XLR out are 6dB hotter (thanks to a balance signal).

You should definitely use Onyx XLR out to TRS CH3 input, with a proper cable. I know you already report to observe the +6dB gain.

My guess is that Bose chose a "gain staging" which my appear weird.

With the input #3 knob at noon, there is only a whisper of sound when I plug a 1/4" trs cable into it;

Noon is probably a wrong position to start with. From the table I've sent, there can be up to 12dB difference between a consumer line level and Pro line level signal. So the "noon" position might be weak.

The Bose CH3 might not have a lots of gain but it has great headroom (+24dB) and the Onyx is capable to drive up to (+28dB), so in theory the Onyx should be able to provide the gain the Bose does not have.

I need to ask: what did you plug into your Onyx mixer? what channel did you use? how did you set the gain on your Onyx mixer?

PS: Bose says all inputs from CH3 works and that the volume pot controls the overall volume for all 3 inputs (Bluetooth, TRS Line, 3.5mm jack). See video at 4:20.

It's impossible to make proper gain staging with one volume pot for such different sources. Probably noon is a very "safe" position in which a crancked bluetooth signal would not blow "peoples" ear.

I would:
1) Set my Onyx Channel level pot/fader on the Onyx to unity (bottom left).
2) Set my Onyx Master level pot/fader to minimum (bottom right).
3) Cranck the volume on CH3 (max or almost)
4) Set the Gain pot correctly on my Onyx. (Raise until clipping then back off a little) (top left)
5) Raise slowly the Master level pot/fader on the Onyx (bottom left) until desired volume is reached.

My 2 cents,
Cuki

[MarkF_48]

Originally Posted by Cuki79

If you read the Onyx manual, the schematic shows indeed that the Main outputs are unbalanced. If you use a TRS jack, the ring & the sleeves are both connected to ground. So using TRS or TS cables between the Onyx and Bose won't change anything.


Cuki

Shouldn't change anything, but I only suggested trying the TS cable as I had a similar experience connecting an unbalanced piece of gear to a balanced line input of a preamp using a TRS cable that did affect the signal level. I also had looked at the Onyx schematic and saw that unbalanced out. Using a TRS cable does ground the ring of the TRS plug at the mixer, but at the Bose which they infer the line in is balanced by stating it's TRS, the ring connection of that input becomes grounded at the Onyx rather than the by sleeve of a TS type plug at the Bose. The unknown is what Bose has for circuitry on that input. I did find a service manual for the L1 Compact which uses a pair of OpAmps in a TL072 to create the balanced in, but they may have done it differently in the Pro8. Again I only suggested this from my own experience. It would be interesting for Michael to try a comparison between the TRS and TS with the mixer again with the settings set the same to see if the volume is perceived to be the same or different.

Good suggestions on setting the levels.

[meb]

Thanks again for the suggestions. I will try to answer some of your
questions here.....in a somewhat random fashion.

I 'did' test ts/ts vs trs/trs and the ts/ts was louder at same settings into ch3.

I tried ch3 volume at 3:00 vs noon and still trs/trs volume was too weak to
use.

Into the Onyx8, I plug:
CH 1 - Mic xlr thru Harmony Singer 2
CH 2- Guitar via XLR DI out from a sunnaudio DI-2
Each Gain knob is in the 11:00 - 11:30 Range ---lots of headroom.
I will try to optimize the staging per Cuki79 suggestion later. Right now,
thru input ch1 1 on Pro8, it doesn't seem to be much of an issue.

When using ch3, only the mixer to Pro8 1/4" plug is used. ...i.e. no BT, etc

New info: I also have a Bose T1 mixer that sounds fine, too. I plan
to use it Wednesday with the Pro8 via Pro8 ch1. I tend to use the T1
solo and the Onyx8 or PROFX10V3 if I have a guest. btw, the trs to Pro8
CH3 also had the low volume issue.

Hopefully, I touched on all the open issues.
Once again thanks.

[Cuki79]

Let's use this thread to explain something about volume pots. (I wrote volume and not gain pots)

Here is a schematic of an analog pot (probably not the Bose L1 pro8 , which is likely to be digital) but most regular amps and analog mixer will use such schematic.

A "volume" pot basically provides attenuation thanks to a variable resistor called "potentiometer".


Given the nature of the potentiometer (linear or log) the pot will react differently with respect to the angle.

On the picture below, one can see that for the Linear pot the noon position leads to -6dB while the Log pot attenuates -16.4dB. The difference is HUGE.


The Bose being probably a digital pot, they can program any response for the pot. However finding a response that works perfectly a 3.5mm consumer line level input, a bluetooth level input and a pro balanced line level input, each with fixed gain is in my opinion a difficult challenge.

My 2 cents,
Cuki

[meb]

I gigged last night with my new Bose Pro8 (with T1 mixer) at a noisy bar
that I play monthly. The Pro8 sailed thru the presentation with ease.
There was plenty of power and I received a lot of complements on my sound.
Most people saw my usual Bose stick and thought I had my usual L1m2.
I have covered this venue with an L1m2, a DBR10, and a K8.2. I found
the L1C lacking.

Some random thoughts.....
I really like the K8.2, but indoors and behind me, the Bose arrays are much
more pleasant to my ear using as a monitor'.
The Pro8 and L1m2 have a strong family resemblance. BTW, the vocals
were incredibly good with the Pro8. The Pro8 has a more 'twangy',
brighter character ....just a slightly different EQ.
The Pro8 self-contained footprint is neat. packing/load-in & load-out
was easier than the L1m2, though I DO wish the Pro8 bass stand was
5 pounds lighter.
First try at setup, the array didn't connect....I had to push it in firmer
to make the connection.....THIS SUCKS for a $1200 product.

Overall, I am pleased. Hope this helps.

[ZebraKing]

Yep I've had the same issue where I need to really force the column into the base to get a connection.

[Chriscom]

Originally Posted by ZebraKing

Yep I've had the same issue where I need to really force the column into the base to get a connection.

I've seen comments like this in the Facebook L1 group as well.

Tip of the hat to Cuki for the detail and graphics in his volume pots post.

[Cuki79]

Originally Posted by Chriscom

Tip of the hat to Cuki for the detail and graphics in his volume pots post.

I did not make the graphics, they come from a french website
https://www.sonelec-musique.com

The website explaines everything a DIY guy should know about analog electronics. Very great source in French. Similar information can be found on ESP website https://sound-au.com.

[meb]

OP here...I thought I would post an epilog to this thread. I now have done a few gigs with the Pro8
and it has worked well. It has plenty of power and the transportability is good.
I liked it enough to purchase a T4s to go with it for ease of connection. It is now my go to PA. I see myself using it even in smaller indoor settings where I might use an S1, since the 2 have a similar footprint and the Pro8 sounds so much better.

Thanks to all for your input and advice.