PackLite® power amplifier Model A1: Difference between revisions

== The [http://www.bose.com/controller?event=VIEW_PRODUCT_PAGE_EVENT&product=packlite&ck=0 PackLite® power amplifier Model A1]  ==

| {{PackLite Extended Bass Package}}  

*[[L1™ PackLite® A1 Amplifer/FAQ|Bose PackLite FAQs]]  

 

 

=== Application Notes ===

For notes on how the {{A1}} works with the rest of the {{PAS}} see [[PS1 Powerstand Bass]].

[http://www.bose.com/pdf/musicians/og_eng_packlite.pdf A1 PackLite® Owners Guide]  

{{:PS1 Powerstand/Bass Line Out}}

[http://bose.infopop.cc/eve/forums/a/tpc/f/3976055944/m/6121039062?r=2531054162#2531054162 originally posted by Kyle-at-Bose in response to questions from Oldghm] October 20, 2005

Note - all references to the system or the L1® are to the {{Classic}}.

In keeping with the premise that musicians should worry less about the gear, the system was designed to be smart about bass management. We did not want you the musician to be tasked with having to re-EQ the system depending on how much bass you decided to use. So, whether you go from zero B1s to 1 B1, to 2 B1, to 4 B1s, the system is making changes to the crossover and level to compensate the fact that you have added (or taken away) bass modules.

We did this so that the system maintains a spectral balance as best as possible so that you didn't have to manage the difference yourself. Of course with zero B1s we are not able to maintain a the wide band down to 40 Hz. The L1 does it's best down to 110 Hz. By adding B1s however the system simply shifts the crossover to 180 Hz, applies active EQ to the B1s and will attenuate the output depending on how many B1s you decide to use. As you add amplification and loudspeakers we gain more overall output in the bass frequencies. To maintain that spectral balance, we simple reduce the signal going out to the B1s (or PackLite amplifier) so that you don't need to fuss with the remote tone controls or have special presets for how many B1s (yikes!). The same tone that you found with presets and tone control adjustments with lower levels (less B1s) is now available at higher levels in those regions (more B1s).

This however is not to say that the L1 will get louder. Bass-heavy instruments like bass guitar and kick drum had a good tone at lower levels with, let's say, a single B1. Unfortunately, these players have probably found that if they needed more punch in larger rooms that a single B1 only went so far and that the L1 continued to get louder. Two B1s give you the ability to substantially get louder in the bass region- more headroom with two B1s. In expansion, 4 B1s give bass players even more headroom to play. (I believe 4 B1s will satisfy most bass players in a variety of larger venues, we've tried 8 B1s and it just seems way too much)

Said another way: As soon as you plug in a PackLite and two B1s, you will not feel a difference in sound. It was designed to perform like this! What you will find is that you NOW have the ability to change your tone. Go ahead, grab the remote tone knobs, change the preset if you want- you now can tailor your bass-heavy instruments in a way that was not so audible before with less B1s.

Yes, that's correct. Fundamental frequencies of those instruments are not present below 80Hz. That is why you'll find 80Hz high-pass switches on so many mixers and microphones- it allows you to trash those unwanted frequencies. In a performance enviornment it halts the pickup of unwanted bass frequencies (instruments, HVAC units, crowd rumble) from bleeding into your mics.

:Hilmar mentioned the crossover being "smart". It changes as more B1's are added.  

Oldghm:

The crossover point is 180Hz  ({{Classic}})

:Is there any way to trick the "smart" crossover, and still get good results from the B1's?

:Is the L1 less, just as, or more, efficient at dispersing those frequencies between 110 hz and 180 hz?  

Hilmar can speak to dispersion patterns better than I can but it's my understanding that 110-180 Hz doesn't do a great job at being a cylindrical wavefront anyway. Considering that it's also in a range that's not perceptibly directional (bass), it was decided to route that down to the B1 that does a much better job reproducing those frequencies. As a listener, we have a hard time hearing where that range is coming from so to the B1 on the floor it goes.

Oldghm:

:Please correct me if I'm wrong, but, can we assume that the crossover drops, lower and lower, as B1's are added? Thus as you add B1's less and less of the acoustic guitar bottom end is actually going to the B1's.

I think the key thing to communicate here is that adding a PackLite(tm) amp and more B1s adds more output when you need it.

Oldghm, the crossover does not change frequency location. It remains at 180 Hz. What I believe Hilmar was talking about is that the system has more low frequency output capability as you add B1s so the EQ adjusts accordingly.

This is a great topic of conversation and it is clearly something we've got to figure out with PackLite marketing materials. It's a complicated thing to communicate.

Here's my attempt to simplify what's going on.

Adding the PackLite(tm) Extended Bass Package (4 B1s total) gives you the ability to have more acoustic output from 180Hz down.

It does not change the spectral balance (acoustic output from 180Hz down) of the system until you reach a volume level that exceeds the capability of 2 B1s.

By the way, you can get more bass by turning the "Bass" knob on the R1 remote and change the spectral balance that you're asking the system to reproduce.

The challenge we have is that we, as musicians and speaker buyers, have been trained to think of buying things in bits. Need more bass, buy more bass speakers and you'll have it. That's because the stuff we buy is not designed to work together.

When an engineer gets to design and optimize the entire solution, they can really do some great things. One of which is make the most out of the output of an amp and a speaker cone working together. That's what the gang here did with the Power Stand and the B1 bass module. They work really well together.

Eventually, as you raise the volume, the acoustic output of the amp and speaker cone reaches its limit and the system says "all done", that's as much bass as I can throw. That's when adding more B1s and a PackLite amp will help ... when you've reached the limit.

It's a pretty hard thing to communicate. We know that a customer is going to be running 2 B1s, hook up a PackLite amp and 2 more B1s and say "hey, there's no noticeable change." and we'll say "yeah, isn't that cool?" to which a customer will say "huh??". Then we say, "well you've added headroom without changing the spectral balance of the system without touching a crossover knob, or an EQ ... just try that with any other speaker system out there" with a big, full of pride, grin on our face.

The customer might then say, "so why buy it?" to which we'll say, "now turn up and down and notice how great the system sounds at any volume without you having to touch any knobs ... it's like bringing Hilmar to your gig to run the volume and EQ controls for your band ... COOL huh?"

Hopefully, with your help we'll find the short way (or analogy) to describing this very cool benefit. Believe me, the engineering team worked hard to give you this benefit. It's real. It would have been WAY easier to develop a solution that was "slap an A1 & 2 more B1s on and boom, more bass; now everything sound good at one volume and muddy at another."

For more see [http://bose.infopop.cc/eve/forums/a/tpc/f/3976055944/m/6121039062?r=2531054162#2531054162 the original discussion]