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I have a question to ask the membership here about the proper place to place a 21 band analog Equalizer to the audio change.
Just a brief description of the equipment involved.
A five channel VMX1000 Behringer (NOT USB) mixing board, using the XLR balanced outputs.
A Behringer Ultra-Dyne Pro DSP9024 six band audio processor using balanced XLR output connectors.
Finally the transmitter, a Decade MS100 FM transmitter operating under 15.239
Now I am trying to decide the best location for the 21 band EQ which has RCA jacks for input and outputs.
If I place it between the mixer board (whose main outputs are XLR connectors) and DSP9024, I am stuck using unbalanced audio cables, to which I have to jumper the COLD and SHIELD together for proper hookup to conventional audio equipment since there is only hot and shield in this case.
If I place it between the DSP9024 and transmitter then I would already have had to go unbalanced since the transmitter has unbalanced inputs anyways.
I want to add EQ to have more control over the audio frequency spread, perhaps block some frequecies while slightly increasing one or two to improve the mid range, while controling the low frequencies from possible pumping, blocking the extreme highs from interfering with the 19KHz pilot tone ect.
If I was to place it before the FM transmitter and after the DSP9024 6 Band processor, would that sound like a logical place to put it, or is it best, to place it before the DSP9024 and deal with unbalanced audio?
Bruce.
Total posts : 45366The EQ has to go right before the DSP9024. If you put the EQ after the Behringer, you’ll lose all the control of the audio levels that the DSP9024 has given you.
Total posts : 45366Hmm, my EQ is a Technical/Pro EQ7153 21 dual band analog device, lights up with nice bright blue LEDs, but now I’m thinking of trying to stick with XLR connectors and balanced audio and not have to change XLRs to RCA plugs, so I am now looking at purchasing the Behringer Ultragraph Pro FBQ6200 31 band EQ and using that instead. (See Google link below)
https://www.google.com/?gws_rd=ssl#q=behringer+fbq6200+ultragraph+pro
Has anybody here ever used this device? Looks pretty useful, it has balanced XLR inputs and outputs and a lot of other useful features.
I see it priced from $170.99 to $199.99 USD new. The reviews that I’ve seen for this EQ are pretty good.
Bruce.
Total posts : 45366I will disagree and say the EQ needs to go after the final processor. An EQ placed before can cause some weird processing related problems. I want to say its common practice to place an external EQ after the processor, atleast thats what the Orban manual says for the 9000A.
Total posts : 45366Agreed.
Total posts : 45366Any multiband eq after the processor will destroy the tight peak control that a good broadcast processor such as the 9000a gives.
The 9000a has hf and lf tilt eq that compensates for transmitter and antenna deficiencies only.
Paul.
Total posts : 45366I am a bit of an audio purist. At one point I had audiophile tendencies. In my opinion, the best place for a 21 band EQ is between the mixer outs and the power amps (or active crossover) in a live sound situation. The narrow Q filters for each slider on a 21 band EQ do horrible things to the phase of audio going through the EQ. Then, the best use for the 21 band EQ is to ring out the system; deeply notching frequencies that want to cause feedback so I can push the entire system louder before feedback starts. In a live sound situation a 21 band EQ could be used to boost the low end and enhance the high end, but both of those tasks would probably have been better done with a parametric EQ. For air chain processing I would prefer to use a parametric EQ.
That being said, for any sort of EQ in an air chain, I would want it before any compression or limiting being used. If I were using any gizmos such as a sonic maximizer or bass enhancer I would want the EQ after them. The reason is the compressor/limiter is a wall keeping the transmitter from clipping, so messing with audio after that would semi defeat the purpose of the compressor/limiter. If I have an EQ in the chain, it is probably to cut frequencies the radio receiving my signal will not play such as FM above 15kHz or AM above 3-5kHz. The gizmos will do their best with the cleanest signal to work with, so they are early in the air chain.
Mixer => gizmos => EQ => Compressor/limiter => transmitter
I have many pieces of Behringer equipment. I was young when I bought it. Now I try to avoid buying it. There is nothing wrong with it, but showing up to run live sound with it makes people not take me seriously. For what I paid for new Behringer gear, I could have picked up big name brand used gear.
Unless you have a RF noise problem or long cable runs keeping balanced audio in your chain does not buy you much. I would not run out and buy a Behringer graphic EQ just for XLR connectors. As I said above, if you are trying to boost or cut broad ranges of frequencies a parametric EQ is a better choice; if you want to spend money consider getting a balanced parametric EQ.
Total posts : 45366A real transmitter has brick wall filtering that sharply cuts at 15,000 Hz. EQ not required.
Total posts : 45366Mighty1650, I will guarantee you that the Orban 9000A manual does not say to put the EQ after the final processor. That’s why boxes like the Orban are called the *final* processor.
What does an EQ do? It adds or subtracts volume in each of its bands. The “final processor” is supposed to take all of the audio fed it, and level it for maximum modulation. If you put an EQ after that, you’re going to have overshoots like crazy which will cause you to have to lower your overall modulation.
I’m wrong on a lot of things, but trust me on this one. I’ve been doing audio processing as a program director, chief operator, and owner for 45 years.
The EQ must always go *before* the final processor.
Total posts : 45366@ #1/Original Poster (MrBruce)
Does your Decade MS100 FM have an option to drive it in Mono with a balanced line? If the line from the final bit of processing to the transmitter is long, I would expect it to be the most likely point for noise to enter. That would make it the best place to use balanced audio. As is, have you seen what range you get a stereo lock? If the stereo range is short compared to your overall range, you might do more good for your listeners with balanced audio compared to stereo audio. If you run your audio in mono, you can get a very nice mono EQ for the same money that would get you a fair stereo EQ. The VMX1000 has a Mono option on the main out.
@ #8/wdcx
If there is a compressor/limiter before the transmitter sending signals above the transmitters cut off, that the transmitter will brick wall, into the compressor/limiter is a waste of headroom. For example, if content between 15k and 20k pushes the compressor over the threshold and it starts compressing, only for the 15k-20k content to be filtered out at the transmitter; uncompressed audio could have gone to the transmitter if the high frequency content had been filtered prior to the transmitter.
Total posts : 45366Domestic fm transmitters usually have pre emphasis and 15khz l/p filtering built in, and are designed for convenience, so that the user just needs a basic audio source to transmit audio.
Pro transmission gear is a different animal, fm transmitters generally have flat wideband inputs, and audio processing, pre emphasis and l/p filtering are done externally with individual boxes or one box that contains processing/pre emphasis and l/p filtering.
Of course going down the pro route is going to cost a lot more money, but the result is pro sound, with precise peak control of audio to the transmitter, and accurate peak controlled fm deviation.
Paul.
Total posts : 45366Okay, if I stick with the Technical pro EQ7153 21 band EQ, I would have to remove the XLR connectors at the end of two cables and replace them with male RCA jacks and short the COLD and SHIELD of the XLR cables. The Behringer owner’s manual states that the COLD and SHIELD have to be shorted together when they are hooked up to conventional equipment, such as those that use RCA type plugs.
I would also need to put together another cable with RCA to XLR connectors, to hook the Technical pro EQ7153 to the Behringer Ultra-Dyne Pro DSP9024 6 band compressor/limiter processor.
The EQ has 21 channels, 21 for the left and 21 for the right, so basically, I can adjust the left stereo channel differenty than the right channel.
The EQ7153 covers 32Hz to 18KHz with 21 sliders. All inputs and outputs are RCA female sockets, no XLR capabilities.
So I am sitting here pondering as to whether I should re-plug the cables and go all un-balanced cables from mixer, EQ, DSP9024 to transmitter still using the XLR audio ports.
Now, I see the majority here, say do it one way, while the other says, do it the other way, why is this?
Just my personal observation here regarding compressor/limiters, I have 3 different compressor/limiters here and one thing I have failed to notice with ANY set up I have tried, is to hear the compressor/limiter actually RAISE the audio when it is too low and DECREASE the audio when it reaches a certain peak!
I have seen a compressor/limiter visually decrease the audio, per LED meters, but really have NOT heard or seen the volume increase when the peaks are negative, or below threshold, (excuse me if “threshold” is the wrong term to use here folks!) the level below where compression/limiting STOPS taking place.
To clairify, I am saying I really have NOT noticed the volume INCREASE during soft passages as people claim compressor/limiters are supposed to allow happen, I HAVE noticed DECREASES when the THRESHOLD is passed though, but have never seen an increase during soft passages.
After all, these devices are supposed to prevent people from having to constantly RIDE the MASTER volume controls, i.e. TURNING IT UP AND DOWN EXCESSIVELY with media having varying volume levels.
The Behringer FBQ6200 EQ is a device I would not be able to purchase until next month anyhow, even if I chose to purchase it.
If some of you out there have your EQ just before the transmitter, do you have any type of Compressor/Limiter also in the chain?
I was asked by stvcmty in post #10 about the Decade MS100 transmitter and there is no balanced inputs, they are conventional RCA female sockets, HOT and SHILED, no HOT, COLD and SHIELD capabilities on this device.
The longest cable in my audio chain is the one that feeds the VMX1000 mixer to the DSP9024, it is about 4 foot long and is 3 conductor wire, red, white and shield wires. Right now, that cable is used as balanced audio cable, XLR female to XLR male plugs X 2 for left and right stereo audio channels.
Bruce.
Total posts : 45366Marosborne is correct in that Orbans, and MOST Processors are designed to be the final stopping place for the audio for the transmitter, most processors also include built in EQ so that it properly mates with the processor.
FWIW, Internally in the Orban unit the EQ Comes AFTER The Compressor but BEFORE The Limiters and Clippers.
The issue from what I can see is the EQ can cause unusual characteristics with the compressor, particuarly with lows that can make the sound get drawn out with excessive bass. This is something I have noticed with cheaper compressors, I’m not sure if this is the same for real pro grade equipment.
Also a question for Marosborne, aren’t the internal EQ settings on processors superior to anything you can get out of a graphic EQ?
Also to answer you on why you don’t see your audio levels rise, compressors don’t do that. You’re thinking of an expander or AGC, compressors “compress” or reduce audio peaks. Theoretically, and something I have done in practice, if you don’t have or can’t afford an AGC/Expander you can raise your overall audio levels until the compressor is always limiting, that way your output levels stay the same. This arrangement can be fatigueing to some however.
Also FWIW, I ran a Graphic EQ after my compressor for the FM with no ill effects.
On the AM station the processing is internal to the transmitter, the graphic EQ is forced to be in front. This arrangement sounds just fine.
Total posts : 45366This site goes into EQ and Compression, it seems you can place the EQ where you want pending on what sound you go for.
https://www.soundonsound.com/sos/oct07/articles/qa1007_1.htm
http://www.sonycreativesoftware.com/the_compressor_eq_question
Total posts : 45366Quick response here since I am annoyed and displeased at the same time.
I changed four XLR connectors and replaced with male RCA plugs to acommodate the EQ7153’s RCA sockets.
Took me three hours, had to remove the XLR connectors first.
The former RED and WHITE wire connections went to the HOT and COLD connection for balanced audio. The white wire is now tied to SHIELD.
Upon firing everything up, I notied the MIXER’s OUTPUT level is wayyyyyy lower than when it was hooked up as HOT, COLD and SHIELD! I had to increase the TRIM, the main channel volume had to be increased and even had to increase the mixer’s MAIN OUTPUT volume control to even come close to the levels it was before! There are no shorts and no solder issues, I checked everything with a VOM meter!
After messing around with 21 sliders for the left stereo channel and adjusting the right to the same levels, I also tried adding a touch of the mixer’s EQ to compliment the external EQ, the end result was lousy, tinny, distorted shiiit! I can by-pass the mixer’s EQ and I did during the first test, I only tried it to see it would help give better control, no go with that idea!
I seen the pilot light blinking on my inferior RCA walmart crap home stereo system, it is an RCA CD 5 disc changer plastic piece of junk with casstte and AM/FM radio and said if that is blinking, even if it is a piece of crap, someone elses crap could do the same!
I kept everything above 800Hz at 0dBu and allowed higher levels from 120Hz up to 650Hz at perhaps 8+ dBu, I blocked the low end 32Hz through 63Hz and also the high end 16KHz through 18KHz!
It totally seems to me like the balanced audio HOT, COLD and SHIELD has better audio for some reason. Like night and day when you factor in balanced versus unbalanced! Just my opinion and I’m sticking to it.
I gave up and called it a day…er night, it’s night to me even though its 9:00AM.
Anyways, wasted 5 hours of my time and accomplished nothing.
By the way, in case anyone isn’t sure, the EQ was placed between the mixing board and the DSP9024. DSP9024 feeding the transmitter.
So far NOT happy with the results, might try again later after many hours of sleep, if I can’t get this working right, I have to change those RCA connectors back to XLRs again and go back to Balanced audio and no EQ…SIGH!
Bruce.
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