Frequently Asked Questions for PLM

Controlling PLM

Do I need a PhD to operate PLM?

A GED will do just fine! If you can press 2 buttons, you can operate Program Length Manager.

Do I need a computer to use PLM?

No. PLM is fully functional as a stand-alone system.

Can PLM be controlled over a network?

Yes. PLM has a built in web server which allows you to control it from a browser over your local area network.

Can PLM interface with station automation systems?

Yes. PLM can work with your existing automation system through the use of GPIO (contact closures). Custom solutions may be possible in the event that you have unique needs or requests. Please contact us to discuss.

Can PLM receive and send contact closures?

Yes. PLM comes standard with a built in 8x8 opto-isolated GPIO system. Contact closure inputs and outputs may be assigned to a variety of useful functions. To help you configure your system, we also supply a GPIO test utility that allows you to fire outputs, and view input statuses.

What happens when a contact closure comes in to fire an ID or Liner, but PLM is running? Won’t the ID fire at the wrong time?

No. PLM’s sophisticated GPIO features allow you flag a contact closure to a piece of audio as it comes in, so that it fires a closure when that audio plays out. Contact closures stay in perfect sync against the audio

If necessary, how can I upgrade the internal software?

25-Seven Systems will send you a software upgrade package. You'll then use the PLM's web interface to upload and install the software. No factory returns, no USB drives, no memory cards. Easy!

Audio Quality

How does PLM compress and expand audio?

We use variable-width analysis windows to simultaneously check the pitch, tempo, and spectral characteristics of the audio. Additional algorithms are applied to preserve musical rhythms and stereo placement. Our proprietary software is the product of years of research into the advantages and pitfalls of other time-compression algorithms.

What is the sound quality of your compressed and expanded audio?

It’s amazingly transparent. We recommend you hear it for yourself. At low rates, you simply don’t know its there. At higher rates, things may seem sped-up or slowed-down, but you don’t hear the glitches, artifacts and grunge that you do with other systems. There is absolutely no change in pitch, ever. Whether you notice it or not becomes really quite content dependent. If you speed up someone who speaks really fast naturally, you may feel his/her speech is just unbelievably fast. But if you are speeding up a snore-inducing talk show guest, even 20% can sound fine, even preferable.

How much audio can PLM store?

PLM can buffer up to fifteen minutes of stereo audio.

My station uses watermarking technology. Will PLM pass audio watermarks?

Yes. 25-Seven Systems conducted tests with a leading digital audio watermarking technology company at the request of a major corporate broadcaster. We ran multiple passes of watermarked test material through our system, at various rates. They reported having “no issues” with our system, even at our highest rate of time compression. We are happy to repeat the experiment for any other provider of watermarking technology.

How good is the analog sound quality?

Converters run PCM linear 16 bit/44.1 kHz, and measure ≥94 dB dynamic range, frequency response ± 0.5dB, 20 Hz - 20 kHz at all levels. In other words, it's CD quality.

What about digital audio?

PLM comes standard with digital I/O, user selectable AES or s/pdif. PLM can accept sample rate inputs of 32, 44.1 and 48kHz. Default operation is 44.1kHz, 16 bit linear PCM.

Interfacing

What audio connectors does PLM have?

XLR male and female connectors for balanced stereo analog, and AES digital audio.

What other interfaces does PLM have?

8x8 GPIO (contact closures) on a DB25 female connector, and a built in web server, accessible over an RJ45 network connector.

Can I drive PLM from my station’s master clock?

Yes. Point PLM at an NTP (network time protocol) server, and it will automatically adjust the unit’s internal clock, which is displayed on the LCD. This NTP server can be located on your station’s LAN, or can be on the Internet.

Wait, I was talking about digital audio clock rates, not time clocks!

Oh! PLM will sync to whatever valid external rate is coming in on the AES input, even if your audio source is analog. That sync signal gets passed to the digital output. If you don’t supply a digital input, PLM uses its own internal 44.1 low jitter digital source.

Technical and Form Factor

 

How large is PLM?

It's 1RU (rack units) high, and measures 19" W (with rack ears) x 12" D x 1.75" H (483 x 305 x 44mm).

How much power does it require?

PLM has an internal 100-240 VAC high-efficiency, self adjusting regulated supply, typical consumption 32 VA.

What about heat dissipation, cooling requirements, maximum operating temp?

PLM does not generate much heat, but its important for it, and any electronic equipment to stay cool. We advise you to mount PLM in a well ventilated cabinet, and to make sure the unit’s rear panel vents are not blocked. For best results, operating temperatures should not exceed 55C/130F internal, 40C/105F ambient.