quote:

Originally posted by Hilmar-at-Bose:
...

A sufficiently sized generator will work with our system although the tend to be fairly noisy.

Car battery converters (so called "inverters") are a little problematic. Most inverters don't work well with our highly-efficient Switch Mode Power Supplies and need to be 2 to 3 times oversized. That draws really big amounts of current from the car battery and the wiring from the battery to the inverter needs to be able to handle that. This is by no means a trivial job, so we recommend against it.

Hope that helps

Hilmar

quote:

Originally posted by Hilmar-at-Bose:

before I answer the technical stuff, please let me try to clarify a few things. Many people think that a 5-string bass need a speaker with a frequency response down to 30 Hz or you wouldn’t be able to hear the low B “properly”.

That’s really not the case. The sound of the bass does not only consist of the actual “fundamental” tone (i.e. 31 Hz in case of the low B) but also many multiples of that frequency (i.e. 62 Hz, 93 Hz, 123 Hz, etc.), which are called the “harmonics”. In fact the amount of energy in the fundamental is relatively small as compared to the rest, so you really don’t loose much by keeping the response low at 30 Hz.

Furthermore, very low frequencies (say below 50 Hz) are not perceptually associated with “bass” or “thump” or “punch” but are much more like an indistinct rumble. We actually have analyzed the frequency content of a lot of recorded music and there is little energy below 50Hz and virtually none below 40Hz. The only type of content that uses very low frequencies regularly is movies. But there it’s not used for musical purposes but as a sound effect, e.g. explosions, starting rockets, a T-Rex stomping along, etc.

In live sound situations very low frequencies tend to make the sound very muddy unless it’s carefully designed fixed installation (as it is in theaters), so most live sound amplification gear will not go particularly low. For example an Ampeg SVT cabinet is only specified down to 55 Hz and most people would claim it does a very adequate job on a 5 string bass.

In fact our B1 goes actually deeper than most other bass cabinets. But it does stop at 40 Hz and does so very abruptly. You will not be able to get any usable energy out of the B1 or the Bass Line Out at 30 Hz. The reason for this is mainly protection. Most bass box designs cannot handle anywhere near the fully rated power below their port tuning frequency and there is no point in trying. They can’t radiate any appreciable amount of sound energy and it’s very possible to damage the driver.

Anyway, if you have a chance, why don’t you just plug in your bass into a double B1 system and let your ears decide whether there is anything missing or not?

Hope that helps

Hilmar

quote:

Here's GuitarPort 2.5 - the most up to date version of GuitarPort software!
This installer has been updated to provide the latest PODxt and GuitarPort drivers as well as Line 6 Monkey 1.10
This free update is:
- Required for Model Pack support
- Required for GuitarPort RiffTracker operation
- Recommended for all GuitarPort hardware users
- Required for compatibility with PODxt Live
- Support PODxt and PODxt Pro Version 2

Complete release notes will be posted soon. In the meantime, here are the basics:

This version brings GuitarPort software in line with many of the additions made to PODxt and PODxt Pro with their Version 2 firmware, including dramatically enhanced overall sound, a new EQ effect block, and improved compressor - and support for Model Packs. There's also a new metronome, plus GuitarPort hardware users will find they now have 24 Cab Models and a the Line 6 Treadplate Amp Model.

Visit www.guitarport.com for more information about GuitarPort, including system requirements.

NOTE: The GuitarPort installer includes Line 6 Monkey, the intelligent updater for PODxt and GuitarPort that gets all your Line 6 hardware and software up to date and lets you access optional add-ons like Model Packs. There is no need to download Line 6 Monkey separately.

quote:

Quoting Hilmar-at-Bose

The channel volume controls have about 40 dB gain from all-the-way-down to all-the-way-up but don't completely mute the sound.

quote:

Originally posted by Chris-at-Bose:
Hi EWong,
I really loved your description of your signal processing demonstration--very apt. But I would like to offer some clarifications on the confusing subject of sound falling off with distance.

What makes the subject confusing is that some people are talking about how intensity falls off and some are talking about how pressure falls off and we don't always make clear which one we mean. (I'm just as guilty of this myself.) But the two quantities don't fall off at the same rate, because intensity is generally proportional to pressure squared, as we'll see below. To make things worse, we also talk about sound in decibels (dBSPL), which is what most hand-held meters give readings in. So a lot of different numbers get used and no wonder it's confusing. ST probably already has a table somewhere that shows all this, but here's my version of the math.

In a spherically spreading sound field,
    pressure
            falls off as "one over r" from the source, ( 1/r )
            drops by half each time you double the distance
    intensity
            falls off as "one over r squared" from the source, ( 1/r^2 )
            drops by one quarter each time you double the distance
    dBSPL (decibels)
            drops by 6 dB each time you double the distance

In a cylindrically spreading sound field,
    pressure
            falls off as "one over square root of r" from the source ( 1/sqrt(r) )
            drops by a factor of 0.7 each time you double the distance
    intensity
            falls off as "one over r" from the source ( 1/r )
            drops by half each time you double the distance
    dBSPL (decibels)
            drops by 3 dB each time you double the distance

From this, you see that the maximum point of confusion is that the phrase "one over r" applies BOTH to the pressure of a spherical source AND to the intensity of a cylindrical source. What this generally boils down to is that you just can't figure out what people are trying to say unless you already know.

The safest thing for all of us to say would be to refer to the dBSPL number, because that quantity is most closely related to the way we judge sound levels with our ears. But I'm afraid we won't be able to retrain ourselves at this late date, so no doubt we'll continue to confuse people when we speak quickly about this phenomenon. But I hope this lengthy explanation allows more people to "already know" what we mean.
Chris

• 1) Mike’s full setup with all 4 L1s and all 8 B1s, called here “4+8”. Left channel is fed to the two left PS1s, right channel to the two right PS1s. All gains equal and preset 00. (It is important to match levels on all 4 L1s. We did this by listening to two at a time, standing equidistant from the pair and tweaking levels in mono until the image was centered. First we did this with the left two, then the inner left and right ones, then the right two. Once they were all matched this way, we turned them all on for the tests.)
  
• 2) Turning off the outer two L1s and their double bass packages gave a standard DJ stereo setup of two double-bass line arrays, called here “2+4”.
  
• 3) A quad bass DJ stereo setup with the same inner two line arrays, using the outer two PS1s to drive only the extra pairs of B1s, called here “2+8”. You would get the same result if you drove the extra B1s with Packlites instead.
  
• 4) One double-bass package alone, called here “1+2”.

quote:

Originally posted by Chris-at-Bose:
Hi folks,

quote:

L1 drop-off was hardly noticable
B1 volume however dropped off halfway the distance of the L1.

As many of you know first-hand, nearby direct sound from the L1 falls off with distance more slowly than most other speakers, including all bass speakers, and including B1s. We rarely notice this difference indoors, because room modes in the bass impose large changes from place to place that dominate over the different rates of fall-off of the direct sound waves from the L1 and B1.

But outdoors, there is nothing to prevent us from noticing that the bass falls off more rapidly with distance than the L1's sound does. This will happen no matter how many B1s we have, no matter what EQ or presets we use, and it will also happen if we use other subs, no matter how big they are. The only ways to fully prevent it would be to either give up the slow fall-off of the L1 or make a line array of bass speakers at least 15 feet tall (wow!), but, aside from the expense, such a thing would be extremely dangerous. So we have to find a way to optimize the effect because we can't make it go away.

Before I explain how to do that, I want to describe the effect in a different way that makes the solution more clear. Since the bass and mid-highs are falling at different rates with distance, there can be only one distance where the balance between bass and mid-highs is "perfect". To my ears, the L1 and B1 achieve this balance point outdoors somewhere in the 10-20 foot range, call it 15 feet. But how much closer or farther must I go to hear a small change in the balance? Human hearing is not very sensitive to small changes in bass level, so 3dB counts as a small change in this frequency region. If I go to either half the distance (7.5 feet) or double the distance (30 feet) I hear a small change of 3dB in the bass balance compared to the ideal. That's because the L1 changes by 3 dB per doubling or halving of distance, while the B1 changes 6 dB, so the difference between them changes 3 dB either way. So there is a large region of distance where the bass is very close to the ideal level and that region covers about a 4 to 1 distance range, in this case about 7.5 to 30 feet.

Now what if I boost the level of the bass by 3dB with a tone control? (A tone control isn't perfect compensation for this effect at all frequencies, but it's not bad.) Now the point of "perfect balance" moves out from about 15 feet to about 30 feet, and the range over which the balance is close to ideal becomes about 15-60 feet, still about a 4 to 1 range. If I boost the bass control even more, the range moves out further, but keeps the 4 to 1 ratio. So now you see how to optimize this effect. Simply apply modest bass boost until the tonal balance is not quite thin at the largest distance you want to cover. Then the balance will be very close to correct from that distance to about 1/4 of that distance. Inside that range, the bass will be modestly stronger than normal, but we all tolerate a little extra bass better than we tolerate too little.

There is one thing to keep in mind when applying this outdoor optimization. You are asking for more bass from your B1s and they may not have more to give at the level you want to deliver. If you try to eliminate the thinness with a bass control and it doesn't increase the bass you hear, then your B1s are already giving all they've got and you will need more B1s (for this job) to get the bass control to have any effect. (Remember that more B1s will not replace the need to use the bass tone control here, because the PS1 keeps the tonal balance the same as you add more B1s.)

But before you invest in more B1s, make sure you are getting all the bass you are entitled to from the ones you have. For stereo music playback, you can get a little more bass by stacking your left and right B1s tight together. Outdoors, if there is a hard wall nearby, you can get a good deal more bass by placing all the B1s right at the wall. If you can't get right to the wall, then keep the B1s at least 7 feet away from the wall. If you place B1s outdoors anywhere from 2 to 7 feet from a hard wall, you will get a big hole in the bass response--bass notes will be very weak at some pitches while other pitches will be okay. The reduction in bass in that case will be significant. Try to avoid such placement if you can.

Overall, outdoor settings demand more from your sound system in the bass than indoor settings, because outdoors there is no bass reinforcement from a room. Also, people are often farther away outdoors. Both factors lead to your often needing more B1s outdoors than indoors. So John L is probably right in his first post--he may need more B1s, but please try these other ideas before getting out your wallet.
Hope this is helpful.
Chris

OUTPUT CHARACTERISTICS MG8/2FX
Connection 	Actual
Source
Impedance 	For Use With
Nominal 	Output Level *1 	Connector
In Mixer
Nominal 	Max. before Clip
ST OUT [L, R] 	150 Ω 	10 kΩ Lines 	+4 dBu (1.23 V) 	+24 dBu (12.3 V) 	Phone Jack (TRS) *6
AUX SEND 	150 Ω 	10 kΩ Lines 	+4 dBu (1.23 V) 	+20 dBu (7.75 V) 	Phone Jack (TRS) *6
CH INSERT OUT (1 – 2) 	150 Ω 	10 kΩ Lines 	0 dBu (0.775 V) 	+20 dBu (7.75 V) 	Phone Jack (TRS) *5
2TR OUT [L, R] 	600 Ω 	10 kΩ Lines 	-10 dBV (245 mV) 	+10 dBV (2.45 V) 	RCA Pin Jack

quote:

Originally posted by Cliff-at-Bose:
Ric

Depends on the wall construction. Most drywall will reinforce midbass (like 100-250 Hz) and let the deeper octave or so pass right on thru giving you little reinforcement from reflection. So if you push your bass boxes up against the wall, you'll tend to get a lot of midbass with a typical drywall-constructed wall. And, yeah, then it will be muddy. Most walls don't reflect sound uniformly with frequency, so you get a change in spectrum you probably don't want no matter what. One possible exception to this is, say, 6" thick concrete with a 1/4" thick lining of steel. Oh, and don't take my word for it either. Do it yourself and see what you hear. Also, aiming the individual bass boxes won't have much effect as they are so much smaller than the wavelengths they are producing that they are virtually omni. For instance, a 125Hz wavelength is on the order of 8 feet. A pair of b1's on each side of your ps1 will give you a hotter midbass down the middle and not so off to the side. Here, you've essentially made a crude bass array. So, my experience with all this tells me that the most consistant way to set the bass up, gig to gig, is to lump the bass boxes together and keep them away from the walls. You won't get the extra bass boost from the walls, but if you did, it wouldn't be wideband. I think you'll always do better not asking the wall to help. You know what they say about free help (you get what you pay for). This works for bass players, dj's and so on.