9024 DSP 6 Band Compressor

[Zozo]

Yes your correct Rev, I haven't been using the 9024 since my first initial tests. I do prefer using real-time hardware processing, more so than using "Stereo Tool" for example. Also the power consumptions of the 9024 is around 38 watts, which is less than a PC, but more than a "Struggling" Raspberry Pi trying to attempt the same feat.

Below is how I configured each of the 6 bands of the processor. These settings seemed to work OK for AM Broadcasting, However I didn't delve to deep into the other parameters of the processing of each passband.

Given the choice of radio for AM Broadcast listening, I'd choose a vintage valve radio, usually because the they’re as Wide as a "Barn Door".

My modern home Hifi component is just an embarrassing afterthought to even include AM, and my car radio is only marginally better in bandwidth frequency response.

The best of how AM can sound is in receivers that are no longer in production, and usually those that think AM sounds bad are only judging it on the rubbish modern receivers they're familiar with. Even early transistorised radios are better than anything produced in the early to mid 1990’s for the home market.

The same problem exists today in DAB radios that include FM. We all know how impressive VHF FM can sound and be, but yet some DAB radios have incorporated the most ghastly of FM receivers money can buy. Painfully slow tuning scan, and poor sounding audio. It's almost an afterthought, or possibly a deliberate attempt to make you switch!?

9024 Settings.png

[LeeCavanagh]

Hey rev, are there any sdr that sound good, my audio on my stick isnt very good with any software (inknow its all just digital, but limited to the usb bandwidth (but 3.4 mips doesnt feel high and output was set too 192 soundcard. Id buy another is quality is more hifi quality.

[mikroman]

Talking about audio quality, as far i tested, last good version of SDR is 1450. So try it!

[LeeCavanagh]

Talking about audio quality, as far i tested, last good version of SDR is 1450. So try it!

Thanks. I will see if I can find it for RTL-sdr if it’s their software. Nooelec

[radioeng7]

I know this is an old thread, I hope somebody is still watching it. Does anybody know the adjustment range of the Low Pass Filter? Can it be set as low as 7kHz? I'm thinking of trying the DSP 9024 on one of my stations. These things really have dropped in price now.

[whitenoise]

I wouldn’t recommend one on any serious station, you much better off using breakaway one with a decent sound card and medium spec pc, then you have an Onnia 9 sound on air. (I know done people don’t like the omnia, and others do, but tweaked properly it’s capable of some great sound , good luck

[radioeng7]

I have an Omnia 9 on one of my FMs, it sounds great. The AM I'm planning the DSP for is just a 1kW talk format so it just needs lots of control to generate density, musically is not necessary. I am trying to get all my stations on digital processors and move the analog processors to backup.

[radioeng7]

Does anybody have any thoughts about using a TC Electronic DBMax Maximizer II for AM? Is it any better than the DSP9024? It has similar features but only 4 bands. It's just for a talk station, I only need basic compression and limiting but good bandwidth control for NRSC compliance. I've been using a Behringer DEQ2496 as a pre-processor for years, it's been perfect for that and should do well feeding either the DSP9024 or the DBMAX. I'm just not sure which I should go with. Other than the number of bands, does anybody think one has an advantage over the other?

[livendirect]

TC Electronic DBMax Maximizer II is unreal for fm and am i have one forsale as just brought a orban 6200 the dbmax as way more than the 9024 its 5 band

[radioeng7]

Thanks for the reply. I have a couple of 6200's on my HD2/3 (USA) stations but they are missing a few things needed for AM. The DBMax appears to be a newer product over the 9024 and you are recommending the BDMax so I'll give one of those a try. Thanks for the reply!

[mpx]

Set band 6 to 7-20khz and then set output gain to the lowest negative setting. A crude LPF but might just do the job

[radioeng7]

The 6200 has a low pass filter that can be set to 7kHz and even lower if desired. The problem is the analog outputs are fixed at +14dbu. You have to adjust the modulation on the transmitter or use an external attenuator. The 6200 also lacks a high pass filter so these together make it not a good fit for AM but usable in a pinch. The DBMAX has both a low and high pass filter. I don't have have one in my hands yet so I don't know how low the low pass filter can be set. But it looks to be more suited for AM than the 6200.

[Albert H]

It's possible to use the DBMAX for AM - I have - but I built an external lowpass filter for its output.

TBH, my favoured processor for AM is the Inovonics 222. It's a doddle to set up, has no processing lag (since it's entirely analogue),l and can sound really great if set up correctly. There are jumpers on the board to set the LPF bandwidth for USA / Europe (though I tighten the filter a bit more for Europe, by tacking a couple of capacitors underneath the board in parallel with the filter capacitors). If you look around, you can get a secondhand one for a really low price these days, since all the numpties insist on digital processors (because they believe the hype, and don't know any better!

[radioeng7]

I've used the 222, it's a great little budget processor for smaller stations. I oversee the engineering for 60 radio stations and there is only 4 of us so reliability is the goal. Analog processors, as they age, tend to have capacitor issues that cause audio and power supply problems that might go un-noticed awhile before you realize you have a problem, especially when your attention is split over 60 stations, most of which you can't even pick up on your radio without driving a couple hours. So my goal is to get reliable digital processors as the mains for all my stations. The FM's are already all digital, I just have a few AM's that still have analog processors on the air. I'll keep the 9100's as back-ups.

[Albert H]

Your experience is directly contrary to mine! I have installed 222's that we put in over 30 years ago, and they're checked every few months, and there haven't been any problems (so far) except for one that was damaged when water got into a transmitter building, and the transmitter was wrecked too!

We've had a few digital units of various sorts that were variously susceptible to RF (!!!), failed in service within their warranty period, or just plain freaked out for no apparent reason! Perhaps the stations we install and maintain are rather lower budget than the 60 stations that you handle. We have installations in dozens of countries, in all sorts of environments, from the Arctic to the Tropics!

For many years, I've believed in the KISS principle - "Keeping It Simple" usually pays off in reliability and maintainability. Many installs have redundancy built-in as protection for continuous service, with quite comprehensive remote monitoring and automated fault reporting. Our philosophy often leads us to not providing the cheapest quote, but we get quite a lot of work because of the obvious reliability built in to our systems.

I've largely retired these days, but still provide some technical support (and design work) when it's needed. I'm now in the happy situation of being able to choose which country I'm going to live in (for most of each year), and have been travelling around, trying to decide!

[radioeng7]

Albert,
That sounds like a fun job you had. iHeart does have a lot of redundancy and remote monitoring in place but I have very few places where I am able to switch in a backup processor remotely. I have had both analog and digital processors fail, this is true. I'll give the DBMAX a try with the Behringer DEQ2496 as a pre-processor and see how it does.

[Albert H]

Drop me a PM, and I can discuss ways of doing very cost-effective remote monitoring.