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Saturday, January 26, 2008

Live Recording - analog, digital, with computer, harddisk recorder?

What are the pros using for live recording (bands)?
Things have changed rapidly in the way that we record live. We used to use a separate mixer and get a feed from the direct outs of the FOH mixer to record the performance. That practice for a long time only changed slightly when digital multi-track recorders became available. Pro-Tools has become the digital recording program of choice for many years, only because it established a foot hold early. Now things have got real interesting as far as new things to come along.

Digidesign has released the live/recording consoles (The Venue Series) which give Pro-Tools users a real good way to mix and record live, of course this would be at the high end.

Friday, January 4, 2008

Muddy Sound from a Sound System with Active Sub Woofers?

Are you having issues with muddy sound from your subs?

Here is a tip:
If possible wire up your subwoofers from a
post fader aux send on the board to a graphic EQ then to the subs. See diagram below:

An alternative wiring schematic for sub woofers

This gives you the ability to send only the channels that you want to the subs. It will clean up your muddy sound and it will give you the ability to dial in your subs with a lot more control.

When you are mixing you don't want any vocals going to the subs or cymbals. All you want is the bass, kick drum, floor tom and possibly some guitar.

This will drastically improve your sound.

Note: The graphic EQ is an option. You don't need it for the subs, but it will help you dial out a frequency that tends to come alive in your room.

Friday, December 28, 2007

What is the best Projector for my Church?


Quantify whether you have the ability to do a rear projection system.

If you can do a rear projection system anything above 2000 lumens will work. Provided the space behind the projector is enclosed and ambient light can be controlled in that enclosure.

What to look for in a projector:

Minimum Lumens: Rear projection (2000)
Front projection (4500)

Contrast Ratio: >1000

Bulb: Arch type Bulb (not filament)

Minimum Bulb life: 2000 hours

Aspect Ratio: Both 4:3 and 16:9 (widescreen)

Resolution: 1280 x 720 (HD) other wise know as 720p (progressive)
1920 x 1080 other wise know as 1080i (interlaced)

If you can, try to find a projector that has sealed optics.

Panasonic has some new models that are liquid cooled and have sealed optics.
PT-D5500U
PT-DW7000U
PT-DW7700U

Sunday, December 23, 2007

Thoughts on the new McCauley M Series Line Array

I recently when to a church service where they had a new McCauley M Series system installed. The configuration consisted of 7 x M-90 modules, 1 x M-120, 2 x MS1 and 1 x AC355 per side. The sanctuary is a 80' x 80' x 26' (WxDxH) with a balcony.

The 2 MS1 cabinets where flown in a separate array next to the main array. I noticed some interesting things (no mids) with lots of sizzle in the high end. They had an acoustic guitar player as well as an electric guitar and you couldn't hear either one. The vocals where not very clear either. Because the array had a vertical coverage of > 90 degrees of coverage, they had some slap back and early reflections in the seating area.

They didn't get as many amps as I thought they should because the boxes are 16 ohm cabinets so they could run up to 6 cabs per amp. This makes it extremely hard to adjust the gain level to the individual boxes to get a good balance in the array pattern (even SPL to seating areas) with that many boxes hooked to the same amp. I sat up in the balcony and it didn't sound full (week coverage) compared to the coverage of the M120s on the downfill (on the floor 3rd row from the front). Overall the best sound was on the floor from the downfill boxes but still no mids.

Believe it or not, this was way better than their old system.
This system would be classified as a 4 way system with the subs included. 2 way out of the M-90 and M120 boxes, third way MS1 box and 4th way out of the sub. The problem here is that the only boxes that are projecting to every seat is the 2 way box. We all know how 2 way boxes behave, they lack mids. The woof can't produce the lower mids and the tweet can't produce upper mids.
While line array systems are a better solution for larger venue (>500 seats), it doesn't guaranty a good system. The clarifiers to a good system are:

  1. Keeping sound off the walls and ceiling (no early reflections into seating areas)
  2. Full frequency to every seat in the venue.
  3. even SPL to all seats in the venue.

The McCauley system installed at this church did not meet any of the above criteria. note: these specs need to be verifiable, not shown with a projected coverage modeler program.
(although the system was better than their old system I predict that they will not be happy with it for long)

The only only Line Array system that I know of that can meet the above criteria is the ISP HDL4210 and HDL4215 systems. They are true 4 way cabinets (5 way when you include the subs) but the important thing is that the each box truly projects full frequency to the seating areas. With 8 speakers per cabinet and dedicated speakers for the lower and upper mids there is no comparison. You have to hear these speakers.

Wednesday, December 5, 2007

Live Recording - analog, digital, with computer, harddisk style recorder, or mixer/recorder stand alone unit?

When you are ready to start "Live Recording" you will find in your research that you have a lot of options. Which one is the best? First you need to put together a couple of lists. One being the intended audience for the final product (target quality), and how to distribute it (internet, CD, DVD, DVD ROM, etc). Once you got that figured out you can start looking at what equipment and process it would take to do that type of recording. So lets look at an example:

We want to record the pastors message and put it on CD and put it up to the Web Site.
Target Quality: CD =
44KHz / 16 bit Internet = mp3 format

Now comes the fun, what do you use to record? You could use a Direct to CD recorder for example: Tascam CD-RW900/901 Standalone CD Recorders
Tascam CD-RW900/901 CD Recorder

But then you still have the internet version to deal with. For that its best to record direct to a computer. So for the above need the best solution would be to record to both at the same time. If you need to edit the material before you release it, the answer would be to skip the Tascam unit and record directly to computer and create 2 files when you are done editing. One for the CD distribution and one for the internet.

Next we will tackle: Live Music recording

Tuesday, November 27, 2007

Selective Hearing? Have you tuned your ears in or are you tuned out?

Have you noticed that if you put your cell phone up to the ear that you don't use, it doesn't sound right. That's because your mind has trained your ear to use the right filters to compensate for the sound that your cell phone puts out.
It doesn't take that long but that is what is happening. If you are an audio engineer, you need to tune your ears.

Tools:

There are tools to help you do that. One of those tools is a good set of headphones. the reason you use headphones is because it takes the room out of the equation.

The next thing you need is something that will give you the tones or frequencies of interest. For live sound your ears need to recognize octave frequency bands. So a tone generator or a CD with those frequencies on it is a must. Once your ears can recognize these frequencies it will give you the ability to find offending frequencies a lot easier then using an EQUALIZER you can take them out if need be. This is essential when you are dialing in monitors.

The next tool would be the ability to dissect a Mix or understand song structure.
Take a song and listen to it and try to map its structure, i.e. chorus, verse 1, chorus, verse 2, bridge, lead solo, verse 3, chorus, so on

Next find the instruments played in each segment.

Then map where they are placed in the mix (extreme left or extreme right, or does it move back and forth) map it in clock degrees. 12:00 being center 7:00 extreme left and 5:00 extreme right this is the part of the mix that bring movement.

Level - what loudness is everything at in the mix. Is the snare drum as loud as the lead vocal? It helps if you use the Lead Vocal as a reference. Map everything in relation to the lead vocal. Pay attention to what happens when the lead vocal drops out. Does another instrument take over?

Texture - or EQ how does that instrument sound. Is it natural sounding or does it sound beyond what the natural instrument is capable of sounding like. Is it deep or thin sounding? This is important because this will help determine genre. i.e. most songs use the same instruments (drums, guitar, bass, vocal) so what is the difference between a country song and a blues song in the way it songs and how we instantly recognize these things

Next on each instrument try to determine if there is an effect (reverb, delay, chorus,) if you don't know what these are you need to find out. this part is important because this determines the depth. Something that has lots of reverb sounds farther away. That is how we determine distance. The more reverb it has we perceive it as being farther away. For example background vocals should be at the same level as the lead vocal but should have more reverb on them to make them seem farther back than the lead vocal.

Last - What is the identifying sound of a Country, Hard Rock, Blues, or Jazz song. Once you can put your finger on these things you will be an excellent audio engineer.




Thursday, November 22, 2007

problems with Mackie SWA1801 Subwoofer and the Fix

I recently had to check the speakers on a pair of Mackie SWA1801 subs for blown speakers. Once I got the front cover off (many bolts) to get access to the speakers I found that the wire that supplies juice to the blue LED was resting on the speaker. I checked the speaker, no noise from pushing in on speaker. The problem was the wire vibrating against the speaker in use. I strapped the wire back, problem solved. I'm not sure if the SWA1501's have the same problem, but if anyone thinks they have a blown speaker they should check the wire first.

The rest of the cabinet was put together quite well considering the cost of these speakers. I checked the amplifier side of the speaker and once I got the amplifier module off, I found everything to be in good order. This is a sealed cabinet and Mackie did a good of sealing. The hole for the wires from the amp module going into the cabinet was sealed with silicone. The only complaint I would have from these subs is the amplifier doesn't have a good enough damping factor to control that 18" speaker. The result is a muddy bottom end.

Saturday, November 17, 2007

Sub Woofers - Why the 180° polarity switch?

There is a reason why that switch is there on sub-woofers. Off topic a little, if you have a cell phone and you are looking for a bluetooth headset you will run into a process called "noise cancellation". What is that and what does that have tot do with subs? The answer is everything.

When 2 sources of sound send audio into a room hitting the same space it causes cancellation. That is the principle behind the noise cancelation devices. This is not a problem for your main speakers if your system is running stereo. But it is a big problem for subs. Usually subs are wired to run mono, and the wavelengths of the sub frequencies are huge. For example a 20Hz signal has a wavelength of 56.2664 ft. How big is your platform? is it 40' or 60' across? A 30Hz signal has a wavelength of 37.5109 ft. So do the subs placed 40' apart cause cancellation? Yes big time. The solution change the polarity on one of the subs. That way when the one sub is on the outward movement the other sub is on the inward movement. You will notice a big change in the sub frequencies.

Tuesday, November 13, 2007

Concerts - Do you go anymore?

When was the last time you went to a concert? I stopped going... why? The sound in the venue was terrible.

The last one I went to was Eric Clapton when he toured with a 40 piece orchestra. I thought that having an orchestra with the band would be great. Surely they would have good sound. Well they didn't. I believe the touring company was Showco and I usually don't to concerts where Showco does sound because they use their own boxes loaded with JBL components. (not a good sound very harsh on high end). I don't know who mixed the show but we didn't hear the orchestra until they got to the unplugged portion of the show. Its funny to see an orchestra playing their hearts out and not hearing a peep from them. There are very few concerts that I have gone to where the sound was great. With the new line array systems out there now, I think I will have to check it out.

Saturday, November 10, 2007

Active or Passive for Main Speakers? Part Two

If you have a system that you are going to add to or just update some components, your existing speakers for example, the passive speakers are your best bet. Unless you are looking to really upgrade to the next level. I am working with a church right now that has a passive speaker system and are upgrading to a line array.
If they go ahead with the new line array system (they are active) some of the components of their existing system will be sold (excess amps and crossovers etc). They have a 6 speaker Turbo Sound 2 way system (main cluster), the subs are a dual 15" and single 18" cabs on each side of the platform, all powered by QSC amplifiers. They have a 80' x 80' sanctuary with a balcony in back (see pic).
We are proposing an ISP Technologies Active Line Array system consisting of either 6 HDL4210 boxes (12° vertical) and 2 XMAX212 active dual 12" horn loaded subs, or 2 Reference Line 4215 boxes and 2 XMAX212 Subs. We are conducting a listening demo during the week before Thanksgiving. This system will greatly improve the music quality of their system. All the other components of their system will stay. I will post pics of the demo and comments from the pastor.
Experience Church