Alesis 3630 Compressor Dynamics Processor

by Alesis

Product Features

• Two independent full-featured compressor/ limiters
• 3630 offers Ratio, Threshold, Attack and Decay controls to customize its compression response for even the toughest signals.
• RMS and Peak compression styles, plus Hard and Soft Knee dynamic curves
• Two fully independent gates with threshold and rate controls
• sidechain for keying or ducking effects

Product Details

• Product Dimensions: 19 x 4 x 1.8 inches ; 2.6 pounds
• Shipping Weight: 5 pounds (View shipping rates and policies)
• Shipping: This item is also available for shipping to select countries outside the U.S.
• Shipping Advisory: This item must be shipped separately from other items in your order. Additional shipping charges will not apply.
• ASIN: B0000WS6UY
• Item model number: 3630 Compressor
• Average Customer Review: 4.3 out of 5 stars  See all reviews (3 customer reviews)
• Amazon Best Sellers Rank: #3,882 in Musical Instruments (See Top 100 in Musical Instruments)

Product Description

Amazon.com Product Description

A great choice for recording, mixdown, instrument rigs, and sound reinforcement, the Alesis 3630 Compressor provides two independent full-featured compressor/ limiters in one rack space while offering excellent sonic quality for any application from studio recording to live sound or broadcast. As an independent dual-channel compressor, the 3630 offers separate controls for two different source signals. Plus, two fully independent gates with threshold and rate controls allow you to easily and efficiently stifle unwanted ambient noise.

The Alesis 3630 Compressor (see larger image).

The 3630 offers Ratio, Threshold, Attack and Decay controls to customize its compression response for even the toughest signals. You can also choose between RMS and Peak compression styles, plus Hard and Soft Knee dynamic curves for every application from subtle gain control to in-your-face punch. Other advanced dynamics processing features include precise signal metering, a sidechain for keying or ducking effects, and stereo linkable operation.

Specifications Threshold (dB): -40 to +20 dB Ratio: 1:1 to inf:1 Attack Times: 0.1 to 200 ms/prog dependent Release Times: 50 ms to 3 seconds Gain Control: Output Bypass Switch: Yes Number of Channels/Stereo Link: 2/Yes Meter Type (VU, LED, etc.): 12-segment LED Main I/O Types (XLR, 1/4-inch, etc.): 1/4-inch Sidechain I/O Types (XLR, 1/4-inch, etc.): 1/4-inch TRS Dimensions: 19 x 1.7 x 4.5 inches (WxHxD)

The Channel A controls. The Channel B controls.

About Compression, Limiting, and Noise Gating

Compression and limiting both affect a signal's dynamic range, although in slightly different ways. This type of signal processing can be used as an effect (e.g., increase a guitar or cymbal's sustain) or for more practical applications, such as avoiding tape saturation or restricting the dynamic range of program material for broadcast applications.

Limiting
A limiter does not affect the signal going through it until that signal reaches a particular threshold. Above this threshold point, the limiter prevents the signal from becoming any louder by providing as much attenuation as is needed to keep the signal from exceeding the threshold. If the signal drops below the threshold, then the limiter "goes back to sleep" and leaves the signal alone unless it exceeds the threshold again.

Hard knee response (above) and soft knee response (below).

If the limiter's clamping action occurs abruptly--in other words, the limiter goes from no limiting to full limiting at the threshold point--the sound's output level will not increase despite changes in input level. This is called a hard knee response and is often used to eliminate loudspeaker or amplifier clipping. With a soft knee response, the limiting action becomes progressively greater past a certain point until it eventually flattens out and clamps the signal fully, just like a hard-knee limiter. This tends to produce a smoother limiting sound that helps smooth out an instrument's dynamic range.

The speed with which a limiter responds to the input signal is also important. If the limiter tries to follow every little nuance of music, the sound can be overly "choppy." Often, you'll want the limiter to affect dynamic range over a somewhat longer period of time. The Release control sets this time period.

Compression
Compression is similar to limiting, but rather than clamp all signals to a constant threshold, the output changes at a lesser rate than the input. For example, with a 4:1 compression ratio (as set with the ratio control), a 4 dB input level change produces a 1 dB output level change; an 8 dB input level change produces a 2 dB output level change.

Noise Gating
To understand a gate's principle of operation, consider a "manual noise gate." Suppose you're listening to an audio signal being processed by a relatively noisy effect. As long as the audio signal is present, its level will generally be higher than the noise, thus masking it. However, when the audio signal goes away, the noise is no longer masked and can be heard.

If you connected a volume control after the noisy effect, you could eliminate the noise by turning down the volume whenever there was no audio signal. Then, as soon as the audio signal (which masks noise) returned, you could turn the volume up again.

A noise gate performs a similar function, but automatically. You set a particular noise gate threshold, and the gate compares the input signal level to that threshold. If the input signal exceeds the threshold, the gate acts like a volume control that's all the way up, and lets the signal through. If the input signal is lower than the threshold, the gate acts like a volume control that's all the way down, and blocks the input from reaching the output. If the threshold is set just above the residual noise level, then the gate will be closed whenever there is hiss, thus giving a quieter signal.

Product Description

Since its introduction, the 3630 Compressor™ has become the most popular dynamics processor ever made. The reason is easy to understand: it provides two independent full-featured compressor/ limiters in one rack space while offering excellent sonic quality for any application from studio recording to live sound or broadcast. The 3630 offers Ratio, Threshold, Attack and Decay controls to customize its compression response for even the toughest signals. You can also choose between RMS and Peak compression styles, plus Hard and Soft Knee dynamic curves for every application from subtle gain control to in-your-face punch. As an independent dual-channel compressor, the 3630 offers separate controls for two different source signals. Plus, two fully independent gates with threshold and rate controls allow you to easily and efficiently stifle unwanted ambient noise. Other advanced dynamics processing features such as precise signal metering, a sidechain for keying or ducking effects and stereo linkable operation make the 3630 the most powerful compressor in its class.

Customer Reviews

Most Helpful Customer Reviews

5.0 out of 5 stars Excellent compressor, November 8, 2011

By 

K. Nguyen (MA, USA) - See all my reviews
(REAL NAME)   

This review is from: Alesis 3630 Compressor Dynamics Processor (Electronics)

I used it for vocal smoothing. Works extremely well.
The compression LED indicator is very useful for making sure not too much compression is applied. (my old dBx 266 did not have this feature).
- Only negative is that it does not have the expander. I don't need that feature anyway.
- Highly recommended (some art of compression needs to be learned).

4.0 out of 5 stars Great sound at a great price, May 7, 2011

By 

Turbo6 - See all my reviews

Amazon Verified Purchase

This review is from: Alesis 3630 Compressor Dynamics Processor (Electronics)

I purchased this compressor/limiter based on the low price and excellent reviews it gets on the internet. I am not a musician or audio engineer.

This unit was purchased to record voice files for the outgoing messages on a new VoIP phone system. My companies phone greetings now sound like we hired a professional voice over professional when it is just me with a little help from an EQ and the Alesis 3630 compressor/limiter giving me that "big radio voice"!

1 of 2 people found the following review helpful:

4.0 out of 5 stars Needed One in a Hurry, January 29, 2011

By 

Robert Smith (Zieglerville, PA, US) - See all my reviews
(REAL NAME)   

Amazon Verified Purchase

This review is from: Alesis 3630 Compressor Dynamics Processor (Electronics)

I was already familiar with the product as a component in our church sound system. After it seems like about 10 years it developed an intermittent condition. After isolating the problem to the Alesis compressor/limiter and finding Amazon.com had a new replacement in stock for an amazing price that included free shipping and 2 day delivery! Thanks to Amazon we were up and running by the next Sunday.