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Roland Anti-Feedback AF-70

My New Toy

Introduction

I am the proud owner of a new AF-70. It seems that it is a new device as of 1999/1998 and I haven't found any web pages about it apart from Roland's. I'm making this web page to show my opinions and comments on the af-70 for those people who are interested in them. If you own an AF-70 I would be interested in finding how much you paid for it.

Overview

  1. Introduction
  2. Overview
  3. Links
  4. What is the AF-70
  5. About the AF-70
  6. Features
  7. Performance
  8. Summary
  9. Comparisons

Links

What is it?

The AF-70 is an automatic, digital parametric equaliser. It also has heaps of other features.

Specs:

The AF-70 uses Adaptive Focus technology in the AD converter which is meant to make it heaps better, but at the moment I don't completley understand how.

The digital conversion specs seems to be above the specs for audio CD so the quality of the shound is good.

About the AF-70

The AF-70 is a black box, if you put 3 of them side by side you have one rack unit. There is an accessory wich allows you to mount 3 in a rack. It looks quite special with the layout of the front panel and the text. I think it would be quite an eye catcher amoungst a stack of PA gear. It comes with 4 stick on feet that you can attach if you want. The BOSS power pack is included, it's the sort that sits on the floor with a mains plug one end and a DC plug on the other. I like these as they don't overwigh and overcrowd your powerboards and they don't make too much RF interferance. If they do, you can just shift it without having to shift your equipment.

Apparently the AF-70 can cause humm if it's sitting too close to an amp. I didn't have any probs with this. It is CE compliant and has the C tick.

 

Features

The AF-70 is packed with features, most of them are brilliant. I only had problems with one of the features: I forgot that the reset button is "child proof" - you need to press it for 3 seconds before it works. The additional features are as follows:

Switch

Description

My setting

Filter wide

Changes the width of the filters - less feedback vs better sound quality

on, esp if feedback is a prob

Dynamic

Turns on the 2 dynamic filters that work in real time to reduce feedback as it occurs.

If feedback still a prob

Diffuse

Changes something to diffuse the feedback and hence reduce it.

Only if feedback still a prob

(blank)

this switch does nothing at all.

Whatever I feel like

Limiter

limits high levels to prevent clipping (i think)

On

Enhancer

Somehow enhances voice

Off. (On if voice is unclear)

Low-cut

Cuts frequencies that are below human voice range - eg thumps on the mike stand

On, depending on conditions

Hi-cut

Cuts frequencies above the human voice - eg hiss

Off, unless hiss or wind noise is a prob.

The AF-70 could be used as a DI box if you are desperate.

Performance

I took the AF-70 across to church yesterday (the 13th of April 1999) to test it. I was quite anxious to see what it would be like. Had I overspent? Would it work well? I was quite nervous as I set it all up. Naturally I had previously read the instructions from cover to cover.

At church I powered up the PA and made sure it was working normally. I had a test listen (my sister was reading recipies into one of the mikes) I wrote down the equaliser settings and set the equaliser to flat or 0 on all 5 bands (I know it's sad and hopeless, but it's one of those all-in-one powered mixers where beggars can't be choosers. The mikes sound a bit better that way as the equaliser is set up for the lapell mike which is hopeless as far as mikes are conscerned. It's an omni-directional mike which has no published frequency response graph, probably because the manufacturers are too emabarrassed. It's frequency range is comparable to that of a telephone. At least its a diversity one. )

I hooked the AF-70 up between the multicore and the mixer, using XLR blanaced leads. After setting up the input and output levels on the AF-70 I took the voume up. I noticed a slight change in the sound, probably because all the options on the AF-70 were turned on. Following the instructions, I set the mixer to normal operating levels, demanded silence and pressed the start button. The AF-70 then started to perform its magic. After a while I heard some ringing, then feedback. It seems to controll the feedback quite well while adjusting itself. After a while the feedback fades to another frequency. It sounds a bit like somebody hitting random gongs at random times. Quite awe-inspiring. After a few seconds, probably about 20-30 seconds at the most it had finished. I tested the microphone and found that it had much better quality and clarity. It sounded well equalised, and possibly like a much more expensive mike. The entire system seemed to be of greater quality, with unbelevable clarity. It's almost like having a properly adjusted 100 band graphic equaliser. Simply amazing. Mikes that cost between $70 and $99 sounded better than Shure SM58s. The mikes I tested were: Realistic (from Tandy) with Shure inserts and Yoga. (I am not endorsing Tandy products. If you want a cheap, good mike, Shure now has the Beta Green series. I'd like to check them out).

Summary

Is an AF-70 worth buying? Is it a good addition to my sound equipment? Does it perform well?

My answer: YES. The AF-70 is a cost effective device that improves the sound quality of your mikes as well as giving you heaps more gain before feedback. The best part is the simplicity of the thing. Flip the switches, Plug it in, dial up normal volume (or the level where it starts to ring) , press start and leave it (don't speak into mike). About 30 seconds later it's all set up, you have a clearer sound, more gain and the feedback comes on more slowly.

Comparisons

Combined with all the extra features the AF-70 is simply marvelous. If I had the money I'd get a few more. Although the AF-70 is a relativley new device, this sort of gadget has been around for quite a while. From my research it seems that the AF-70 is the cheapest in its class. As far as I can see other devices include:


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