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Author Topic: Quality of Components?  (Read 8401 times)

Frank DeWitt

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Re: Quality of Components?
« Reply #10 on: February 12, 2011, 03:13:54 pm »

Perhaps the moderator will jump in on a new thread.  "Looking for a consultant" is difference then Quality of components.  Also, you may want to join Church sound check  http://www.churchsoundcheck.com/list.html just to get some more exposure.

Between Cincinnati and Dayton I bet there are some good Christian professionals and some satisfied customers who know they are good.  I am over in central NY so my contacts won't help.

Frank
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chuck clark

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Re: Quality of Components?
« Reply #11 on: February 14, 2011, 09:20:39 pm »

Hi Jacb. The first system you list is pretty cool, with the following caveats.
The bag end woofers are a bit shy on max output capability. A general rule of thumb is if your going to put live kick through it, you'll want 15's.  2 10's is lovely for bass guitar but think "physics". If your total cone area is less than a kick drum head, how is it going to "re-inforce" kick drum?  Good luck.
The monitors don't have subs so you'll probly want at least a 10" there. (again, it can get ugly when you put kick thru an 8". Oh the humanity!)
Make the amps 2000's so you have a little overhead. 1000's tend to run out of gas a couple blocks from the gas station if you know what I mean, heh.
Chuck
Oh, a driverack is dandy for this system. I don't think you need the 260, your not tri-amping, so save some money there.
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Matthias Heitzer

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Re: Quality of Components?
« Reply #12 on: February 15, 2011, 06:04:02 am »

Crown XTIs have their own dsp, so there is no real need for a driverack.
On the other hand, you could use normal amplifiers and a simple 2 way dsp controller.
Just do a bit of math and find out what's cheaper.

I've never seen nor heard that bagend woofer, but it seems to be made for other applications than a church. the bagend homepage list it under home/hifi speakers.

The already low sensitivity of 92db/1W/1m is at 80Hz, it is a small sealed woofer that reminds me of URPS (under resonance principle subwoofer, or something like that, i hate those abbreviations)

That means: below its resonace frequency, every CB has a steep but even roll-off. The cabinet is so small, that the resonance frequency is (or is above) the highest tone the sub is designed to reproduce. Now we take an EQ and create a filter that looks just the opposite of the frequencyresponse of the cabinet. Amp power is cheap and modern speakers can handle huge power.
That's an easy way to get a smooth sub response, but the cost is a ridiculously low sensitivity.
I know there are some people who implement this principle in live reinforcement systems, but then we talk about stacks of 32 or 64  10" or 12" drivers
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Brad Weber

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Re: Quality of Components?
« Reply #13 on: February 15, 2011, 08:22:06 am »

I think the last couple of posts from Chuck and Matthias maybe unintentionally hit on an issue that hadn't been addressed.  If you go to a design/build firm they are going to put togther a system for you based on the equipment they sell.  They may spend time with you establishing your goals or they may feel they already know what you need.  They may be proposing a very good solution intended to serve you well or they may be proposing what they want to sell you.  However, they will be proposing whatever a solution and they may or may not be open to your wanting to change the design concept or specific products.  The reasons behind that may be that they don't sell the products involved or feel comfortable with anything new.  Or it may be because they have carefully thought everything through and put together what they really believe is the best possible solution.

The difference with a Consultant is that in theory they have no limitations in terms of products and have no financial interest in applying specific products.  It's not that they necessarily know more or don't have product preferences, it's supposed to be that their only interest is supporting you without influence from dealer agreements, potential product sales, profit margins on products, etc.  The tradeoff is that because these services are not related to product sales or the resulting profit, they have to be compensated for directly.  Quite frankly, the detailed design effort noted, such as computer modeling,  is often impractical with smaller budgets.

What you may want to do is to ask the vendors how the equipment translates into results.  I've run into very few churches for which the equipment used is the goal, they are usually thinking more in terms of functionality and performance.  So what are you getting for your money not in terms of an equipment list but rather in terms of the actual system performance and capabilities?  This is also another way I've worked as a Consultant with churches, not developing a full design but rather helping develop a package defining their overall goals and expectations, and also defining expectations such as testing, training, earranty, documentation and so on, that can then be provided to design/build companies and their responses assessed in terms of price and how well the proposed solutions appear to comply with the goals defined.  But if you are comfortable doing so that is something that can potentially be done in-house without any assistance.

As far as specifics, the first system you noted is definitely a compact system with dual 8" woofer mains, dual 10" subs, 8" woofer monitors, etc.  The Bag End DS10E-I is part of Bag End's pro series, although probably at the bottom of that series.  It does indeed operate under resonance, so the physics are a bit different.  And with the ELF Integrator it can provide broad, very low frequency response, they are actually quite amazing in terms of the low frequency response possible from a small box.  However, that extended low frequency response is typically achieved at the expense of output.  So while I would not generalize performance based solely on the size of the drivers as there are many other potential factors, the products listed for that system are going to relate to less system output and thus less level at the listeners.  I have to admit that I don't understand the DriveRack PA+ when the XTi amps have pretty much the same processing integrated into them.

I also agree with Frank's comment regarding focusing on the speaker system.  Speaker systems are usually one of the more difficult aspects of a sound system to get right as well as one of the more expensive and difficult to change, a combination that makes you want to get it right the first time.  Having a good speaker system is also more likely to let you immediately notice any other improvements to the system.

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chuck clark

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Re: Quality of Components?
« Reply #14 on: February 16, 2011, 10:02:43 pm »

Gee, I knew the XTi amps had a crossover in them but the driverack has input compression, pink noise, pink noise measurement mic input, 3 way stereo crossover, output limiters, dual 1/3 octave eq, parametric eq and a lot of well known spkr. presets. What's in that XTi DSP these days? (I use powerlight amps and always look for infrasonic filtering and input clipping eliminaters on any amp I recommend)
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Brad Weber

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Re: Quality of Components?
« Reply #15 on: February 17, 2011, 07:40:00 am »

Gee, I knew the XTi amps had a crossover in them but the driverack has input compression, pink noise, pink noise measurement mic input, 3 way stereo crossover, output limiters, dual 1/3 octave eq, parametric eq and a lot of well known spkr. presets. What's in that XTi DSP these days? (I use powerlight amps and always look for infrasonic filtering and input clipping eliminaters on any amp I recommend)
Keep in mind that Crown and dbx are both part of Harman, so guess where the XTi's DSP likely comes from?  It seems to make sense to use what you can from an existing Harman product, so I'll bet that the processing in the Crown XTi is based on the processing in products like the dbx PA+.

The XTi processing includes a stereo/parallel/summed mono mode selection, then for each channel there are six parametric filters, high and low pass filters with choice of Butterworth or L-R and slope, digital bandpass gain, limiter, delay (up to 50ms total), polarity and finally a digital attenuator.  And there are presets.  So while you don't have the compression, subharmonic synthesizer, AFS filters, graphic EQ or measurement function of the PA+, I personally would rarely use those functions in a system processor and the XTi probably provides all the processing needed for most typical applications of these products.

On more complex projects I often use dedicated speaker/array DSP processing and an overall system processor, the latter being user accessible for graphic EQ, different routing presets, etc. while the speaker/array processing remain untouched once set.

Another thing to consider in this particular application is that you have two channels of mains/subs and two channels of monitors, but the dbx PA+ has only two input channels.  So either the PA+ is assigned just to monitors or you are relying on just the processing in the monitor amp for the monitor processing, which for an installed system seems to be the processing one most likely needs to change on any regular basis.
« Last Edit: February 17, 2011, 12:20:06 pm by Brad Weber »
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Arnold B. Krueger

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Re: Quality of Components?
« Reply #16 on: February 17, 2011, 07:55:53 am »

Gee, I knew the XTi amps had a crossover in them but the driverack has input compression, pink noise, pink noise measurement mic input, 3 way stereo crossover, output limiters, dual 1/3 octave eq, parametric eq and a lot of well known spkr. presets. What's in that XTi DSP these days? (I use powerlight amps and always look for infrasonic filtering and input clipping eliminaters on any amp I recommend)

I guess google is broken on your computer, because the easy-to-find  XTi datasheet says that the XTi DSP provides:

"crossover,  EQ, limiting, delay, and a subharmonic synthesizer"
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Michael Galica

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Re: Quality of Components?
« Reply #17 on: February 17, 2011, 10:56:10 am »

Hi Jacb. The first system you list is pretty cool, with the following caveats.
The bag end woofers are a bit shy on max output capability. A general rule of thumb is if your going to put live kick through it, you'll want 15's.  2 10's is lovely for bass guitar but think "physics". If your total cone area is less than a kick drum head, how is it going to "re-inforce" kick drum?  Good luck.

Umm, can you throw some math to back that up?  I've done just fine with a single 18" Mackie powered sub "reinforcing" a 22" kick drum.  Ditto with a single LA400, and that's a 12" driver.
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Mike Galica
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Matthias Heitzer

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Re: Quality of Components?
« Reply #18 on: February 18, 2011, 05:37:26 am »

Pressure is force per area (thats were psi comes from), so you simply need more force if the area is smaller.
Since the air is a giant spring that affects both the drum and the subwoofer we can also look at the cone (head) traveldistance.

Bassdrums are partially comparable with dipole subs, there is an acoustic short circuit between the two heads (dependent on the tuning) that eats up parts of the emitted energy.

So don't worry to much about cone area, two 10" speakers have a similiar cone area as a 15", the only problem i see ist the low sensitivity of this 2x10" woofer.
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Michael Galica

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Re: Quality of Components?
« Reply #19 on: February 18, 2011, 09:50:52 am »

Pressure is force per area (thats were psi comes from), so you simply need more force if the area is smaller.

Yes, that's what I was getting at.  When I read Clark's post it seemed he was leaving out the force component behind it.
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Mike Galica
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Holy Cross Lutheran Church
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