PRAS – Parametric Receive Audio System
The Heil Parametric Receive Audio System (PRAS) is a state-of-the-art audio system that enhances the internal audio systems of amateur radio, shortwave, commercial, and CB receivers. The PRAS allows radio operators to modify, shape, and improve the audio output of their receivers using three separate equalization controls.
Midrange frequencies are the most critical for achieving clear voice articulation in receive audio. The Parametric Receive Audio System allows operators to have unique control over these important frequencies. First, operators can adjust the parametric midrange filter from 400 Hz through 4 kHz, with the recommended sweet spot being at 2.5 kHz. In addition, operators can control the presence of these midrange frequencies plus or minus 15 dB. Combined with a low-frequency filter down to 160 Hz, and a high-frequency filter up to 6 kHz, the Parametric Receive System provides operators unparalleled control and quality of their receive audio.
The PRAS has three audio inputs: standard XLR and 1/8” inputs, and an 8 ohm input that can be used with the 8 ohm speaker output of any receiver.
There are three audio outputs on the PRAS: balanced XLR and 1/4” outputs on the rear panel, and a 1/8” output on the front panel for recording audio. The PRAS also has two built-in headphone amplifiers with separate level controls and dual 1/8” headphone outputs.
The PRAS is intended to be used with the Heil HPS-5 powered speaker (the PRAS must be used with a powered speaker). The HPS-5 consists of a 24-watt, two-way, low-distortion amplifier using a titanium midrange tweeter and a 5” low-frequency speaker. The HPS-5, in combination with the PRAS, provides superb audio balance without distortion.
The PRAS comes with an XLR-to-XLR cable to connect to the HPS-5, as well as a 12-volt DC power supply.
HPS-5 – Heil Powered Speaker with 5” Driver
The Heil Powered Speaker (HPS-5) is a two-way, powered speaker designed to be used with the Heil Parametric Receive Audio System (PRAS). The HPS-5 in combination with the PRAS provides unmatched speech articulation and brings new dimensions to receive audio quality. The end result is a fantastic listening experience that relieves ear fatigue for operators.
The HPS-5 has a low-distortion, highly efficient Class D 24-watt amplifier that drives a specially designed 5” low-frequency speaker with a 3” magnet assembly mounted in a resonant sealed enclosure. A passive extended crossover drives a 2” high-frequency tweeter.
The HPS-5 has two rear panel inputs: a balanced 600 ohm XLR input and an unbalanced 1/8” input. A single level control adjusts the input signals for both inputs. There is also a balanced 600 ohm XLR output for combining two or more HPS-5 powered speakers. Included with the HPS-5 is a 12 volt, 2 amp power supply, and a 2 amp fuse is mounted on the rear panel. Dimensions are 9” H x 7” W x 6” D.
Now Shipping!
Why has not someone thought of this sooner? I witnessed the introduction of this amazing system at Hamcation in February! I was focused on other devices that I felt only Heil could deliver and was soon educated on creation of this amazing device! This will be a great system for those who do not like to wear headphones or are challenged with hearing! I have been enjoying this hobby for a relatively short time and the poor sound quality of rigs was one of the first thing that I noticed. I will be buying one of these systems when available (hopefully at Xenia) if not sooner! Thank You Heil Sound!
Thank you for your nice note. Yes, one of the main focus points as I was in the initial design was that many fellows have a loss of hearing right in the speech range. Blue tooth, noise cancelling and all of that type of thing is NOT the answer. The answer is a Parametric equalization which is easy to control and set to your exact needs. The speaker system is terrific. As a student of the great Paul Klipsch, he taught me how to tune speakers to an enclosure. Using one of our own white cone 5″, I did just that. Added a 3.5″ titanium tweeter all driven by our own 25 watt at .1% amplifier. II also included two very clean headphone amplifiers so we cover all of the bases. See you early Friday at Dayton.
I look forward to visiting your booth and your team at Hamvention! This will be one of my first stops! I will be volunteering at the information booth first thing Friday morning so I may not get over to check out the equipment until after noon! cannot wait to get the Parametric Equalizer in my shack!
Thanks Bob. I have hearing loss due to military conditions. The VA finally listened to me saying I had ringing in the ears. Turns out I had a loss of high frequency hearing. They finally fitted me with hearing aids and I can’t believe how much I can now hear. When working outside I can’t believe all the birds I can now hear. It makes it tinny which I am sure this new unit will help with. They fixed me up with a unit to hook to any 1/8 inch stereo jack like the TV has or my radio putting the sound straight to the hearing aids. I look forward to plugging this unit into your new unit to see what it will do for my hearing. I either turn them off or remove them if I don’t want to hear the wife. It makes for quiet sleeping when I remove them. Thanks for all you are doing for us. de N7HRO
Dennis,
The PRAS is a revolutionary product and will be of great benefit when listening to your receiver. Look forward to hearing your report. Will be shipping first week or so of September.
BOB
i got your pr 781 and your ppt switch and thank of this can i still get a combo set ? using this on galaxy 94hp with a sweet 16 thank you bob
brian
Revolutionary !
were can i buy one been looking but can,t see were
You may purchase one from most of our dealers or you can click on this link to buy directly from us. https://heil-sound-ltd.myshopify.com/products/pras-equalizer-only?_pos=1&_sid=469efc7ba&_ss=r
Way to go, Bob !
de AB0LX, Tom
Bob,
Was about to order an Alexsys Multi-Mix8 mixer and JBL Control 2P powered speakers….this looks fantastic….
Awaiting it’s availability for sale!
Jeff
N5ITU
Fairview (Dallas) Texas
Hi Jeff
Yes, you will want to check this out. Truly the answer to receiving audio and nothing – absolutely nothing has ever been done like this before. It truly is groundbreaking technology. We will have a demo of it at Dayton/Xenia.
Looking forward to this being available… are you going to sell direct? Or through folks like HRO?
Thanks and 73
We will be selling through our dealers.
Is there a “through/bypass” kind of function to be able to easily compare unprocessed to processed audio on the same speaker?
It does not have a through/bypass function.
Stan
Thanks for your interest. No need for a bypass….simply return the three filters to 12 o’clock…center up. Started shipping today. Please contact your dealer or best to call 618 257 3000
Hi Jeff
Started shipping today. Contact your dealer or call direct. 618 257 3000
Awesome!!! Finally a parametric EQ, built by a Ham, for Ham’s! So glad to see Doctor Bob… Hope us cheap Ham’s, can afford and would be glad to evaluate…
Hi Dean
Thanks for your nice comment. Yes, this has been a big problem with equalization units. They are designed for music. Took me two years and hundreds of hours of listening and tweaking to get it right. The PRAS is really right on. We will have a great demo at Dayton.
It will definitely be affordable.
Perhaps a preview at Dayton?
You are a Master Teacher! Thanks for being such a great Elmer on Ham Nation.
Thanks KD2EFR
James Salyer
Hello
Thanks for your nice comment. Yes, this has been a big problem with equalization units. They are designed for music. Took me two years and hundreds of hours of listening and tweaking to get it right. The PRAS is really right on. We will have a great demo at Dayton.
It will definitely be affordable.
This is a must have! I watch Ham Nation without fail and when I saw you demonstrate this I was amazed. I am 71 years old and have very bad hearing loss. This is a GOD send. Thank you Bob, You are my hero!
John K4AGO
Thank you, John. Yes, the PRAS will be of great benefit to all of us….. especially those that have any frequency losses.
Bob is this item stereo as most high end radios have two receivers and need two channels?
This processor is only mono.
I’m going to be at the Heil booth early Friday morning in Xenia!
I just saw this advertised in QST magazine and went HOORAY! I have been watching Ham Nation from the beginning and am fascinated with audio quality (or lack thereof) of amateur radio and how I can make my station better. I came very close to buying a mixer for my station but held off.
From the little I know about the receiver, it appears you have incorporated all the features you talk about on Ham Nation in one box.
Can’t wait for this to arrive in the stores.
Thank you Dr. Heil!
The PRAS started shipping today. Best to call direct. 618 257 3000. or contact your dealer
This will be an awesome add on to any shack, always wanted to try this with an EQ because a lot of speakers are a lot to be desired and it’s hard a lot of the time to pick the weak audio signals out of the hash on the bands. Glad to see you bringing this to Ham radio. Can’t wait to try one. Thanks Bob for all your dedication to the Ham community.
Any thoughts of a balance control for headphone use for us symmetrically challenged folks who use stereo headsets without onboard balance ? Could even be rear panel knob or through panel holes for tweaker insertion. PROBABLY NOT LIKELY NEEDED ON DAILY BASIS
Looks like a well thought out design, should have an incredible user base.
Warm Regards.
___
Rob
N9DTT
Hi Rob. I love it when I get ideas from my fellow hams…. the balance Is a great idea. You got me thinking,, Rob. We already have this available on the PRAS. Here’s. how. The PRAS has two seperate headphone amplifiers with separate levels. Building a very simple adapter (maybe something we need to add to our line) . The adapter will bring the right headphone speaker to one of our headphone amps and the left speaker to the second headphone amps ! WOW – another feature I didn’t think of and that works really well !
Great Job!, I unfortunately purchased the behringer 802 mixer and the JBL control 2P speakers. Is this unit of yours going to work better than this setup. I had seen your youtube video regarding this setup and purchased it. So I am now wondering if I should sell off what I have and go with your setup?? What do you think
Jeff Ab1wt
The JBL and Behringer are both nice products that we often use for presentations. The PRAS and HPS-5 though are specifically tuned for amateur radio use and to help hams carve out nice articulate receive audio.
Will the new mixer work with Index Labs new 80/40 super RF AM transceiver
Richard, the PRAS will work with ANY receiver.
Hi Michelle, the Pras and the HPS-5 sound like they are going to work well with HF. The setup I have now is nice but lacks some of the audio range I wish I could adjust with HF radio. I have decided to purchase the Pras/HPS-5 this fall and can’t wait. Thanks for replying.
Jeff AB1WT
Fantastic!
How does this differ from an EQ? or is it the same thing? Thanks
Hi Mike
TH PRAS is much more than just an EQ. It has a two-band shelving EQ for Bass and treble and the all-important MIDS are controlled by a Parametric EQ so you can adjust the FREQUENCY of that mid filter to where you need for maximum speech articulation.
What are the expected dimensions for the PRAS?
Thanks.
Bill N2RR
The PRAS is 10″ x 7.5″ x 2.5″ and the HPS-5 is 9.75 x 7 x 7.25.
Thank you Bob I am a new ham and was thinking of taking your advice and going with the JBL and mixer but now I’ll have to wait till this setup comes out. I have a Kenwood ts 2000 with a Hell gold line mic love it the receive sound is lacking so bring it on, I would even be a tester if you need one, being relatively new I have no real bad habits or bius. Thank you 73 Rick kw9jkn
Hi Mike
Thanks for your note. Saying you have an ‘EQ’ means many different things. Many different types of “EQ”. The various filters are set for the maximum performance of music and these frequencies are of little benefit to speech and especially the narrow (3K) bandwidth audio of Amateur Radio. I have designed the PRAS after years of research, study and actual application and trials listening to actual signals from a receiver. I have the Low and High filters set at 160 Hz and 6kHz respectively with + or – 12 dB that will allow you to trim off some high-end noise and “tubby” and muddy low-end bass tones. The most important for the human voice is in the mid-range – as discovered by Bell Labs and Dr. Fletcher and Dr. Munson (google them) back in the early 1930’s. I, therefore, designed the mid-range to Parametric so you can dial in the right freaky of the voices you are listening 400 Hz through 4k Hz. Look forward to helping you get all set with your PRAS.
I am excited to read about the new product. I’m not at Dayton this year, but will be watching the posted feedback.
(I met you last year, I bought a PR-77)
Which brings out a question…. I know it is tailored for speech, but what would a pair of the speakers sound like for music? I know there are loads of good music speakers out there, but I’m not aware of any with a Heil logo.
73, Graham
9k2/vo1dza
This speaker is not designed for music use. It is specifically designed for ham radio use.
Cool Bob, dog gone it with my hearing issue I wear headphones or the intelligibility of voice just doesn’t work for me. I sure wish I could use it with phones. Been awhile since we QSO, glad things are going well. 73, Richard W9RAC
You can use the speaker or headphones with the PRAS.
COOL, sign me up I’ll take one. Tnx
Hi Richard
Hope you are well. The PRAS is a tremendous move forward for those that have a hearing deficiency situation.
Nothing has ever been done like this before and all of the shows and conventions where it has been introduced have many of the fellows in line immediately. I am certain it will help you.
The PRAS started shipping today. Best to call direct 618 257 3000 or the dealers will begin receiving them in a week or two.
Let’s get together again, soon
Want two. Went to purchase Sat at Hamvention, the 20ish that they brought were ALL GONE.
Sounds good to us! We will certainly be getting the word out when they are available.
That’s the luck right? I missed Dayton this year so I didn’t even have that opportunity! I use Bobs old Crate Audio Studio Modules on a FT2000D and they perform great at about 40 on the MIC gain. I am sure we will both enjoy the new system when they are avail. 73 Gary, de N0GB.
The PRAS started shipping today. Best to call direct. 618 257 3000
I am 79 years old a ware two hearing aids I use your pro 7 headsets. With the aids removed they make qso’s enjoyable.
My question is will the Pras. I prove the preferences of the pros headset?
Ps:
When using the headset with the aids I get severe feedback .
Hi Vic, those pro 7s are pretty tight on the ear. I would recommend trying to use them without the aids in. you probably already have tried. Also, try lowering the RX vol on both your rig and your aids. The reason I say that is because those cans are so tight on the ear that I’m sure it will automatically create a feedback loop on the RX. try a Bluetooth adapter for your rig and pair it with your aids. that might help. I am definitely not an audiologist. just trying to make suggestions based off of the old school feedback on conventional rig setups. I hope this helps. 73 de N0GB
I am looking forward to this system. I’ve been using Bobs Crate Studio modules from a while ago. the audio is second to none paired with the 781 and a FT2000D. I will definitely be adding this to the FTDX3000 ASAP!
PRAS started shipping today. Best to call direct 618 257 3000 or contact your dealer.
I note that this is a mono only equaliser. If one is using a transceiver such as a Flexradio 5000a which has two separate receivers, could one use two of these EQs so that each channel is processed seperately? Any idea of what the estimated price is going to be?
Hello Hugh
Yes, I have designed the system so two will stack perfectly and you have full control of each receiver.
The Suggested retail price is $499.00 for the PRAS and that includes the HPS-5 25-watt speaker.
Thanks
BOB HEIL
After reading this thread and dealing with significant Summer QRN on HF SSB, I was wondering what, if anything, the PRAS will do to improve QRN noise reduction?
What is the release date ?????????????????
Hi Bob,
Could you let me know when this is on the market please.
I wear Hearing Aids and when I had a Kenwood 480HX I had no trouble with the receive audio as it had good array of adjustments however when I updated to a Yaesu 991 I am having trouble with the receive audio as there aren’t the adjustments that Kenwood had so I am looking forward to this coming on the market
Hello!
I was wondering what the differences are between the PRAS and the BHI ParaPro EQ 20? I almost bought the BHI but held off when I saw the PRAS.
Best 73……Barry Norman KF4WGR
Hi Barry
The PRAS is pure analog. No blue tooth, no digs-wigi DSP it is ALL analog. The quality of the audio is stunning. I have done everything possible to keep the audio clean. There is nothing that will come close.
Looking forward to helping you.
Bob
Please let me know when the EQ and speakers will be available for sale
Hi Dave
PRAS began shipping today. Contact your dealer or best to call direct 618 275 3000
Thanks
Great idea! Only thing that would make this better is for it to have inputs from multiple radios. I would like to see a ‘mixer’ if you will that would allow for 1 microphone to be used with multiple radios. It would cut down on clutter in our radio room at work.
Hi Westly’
Thanks for you interest. Working on that very thing so stay tuned. The PRAS started shipping TODAY! Aug. 27 so contact your dealer or better yet, Call us direct. 618 257 3000
Are these units available yet if they where at Dayton I’m assuming they are? If so how much are they?
They are not yet available. We will keep everyone posted.
PRAS started shipping today….. best to call direct. 618 257 3000. or contact your dealer
Hey Bob & Heil 🙂 Totally Awesome!!! Cant wait to add this to the shack my friend. . awaiting relese date 😉 73 de Ira- VP2EIH
TIs is good news thanks Bob can’t wait to get one for my shack from ZS5SS.
How well will these products be shielded against RF? My current problem with a mixer/powered speaker combo is my transmit audio coming out the speakers.
Really love the concept … 499.00 each requires 2 units to support an Icom 7610 with dual receivers … can’t justify 1k for 2 units. Please consider adding dual input. Today’s radios are offering dual independent receivers and the lack of 2 inputs with adding a second optional speaker would make this an automatic buy with an optional 2nd speaker a bigger winner!
PRAS starts shipping today.
Hi Bob,
Do you have an agent in Australia for this product the PRAS?
Met you at Dayton this year and you were very helpful re buying the right mic for my IC-7610.
Will you be at Friedrichshafen Ham Radio Convention next year?
Best regards,
TEX VK1TX
We have a dealer in Australia Strictly Ham, but they have not ordered any units yet. You might let them know that you are interested.
Neither Heil Sound nor Bob will be attending Friedrichshafen next year. Thanks!
Sir,
Thanks so much for the demo of the PRAS at Huntsville. WOW – what a great idea you had for us old guys that are loosing our hearing. I was lucky enough to get one ordered today. Jake and I are looking forward to its arrival in the next few days. Thanks Bob !
RJ and Jake
KC4LRR
It was a pleasure as always talking to Bob at the Joplin hamfest on Saturday 25 August. This new device made even the worst audio sound great and only Heil sound could pull it off. I own two of their desk mics and a Pro7 headset with various adapters also the foot switch and they are all great.
73 Bob and your crew and thanks for building quality products in America. Jerry W0PP
Bob demo’d his new PRAS for me at his booth at the Dayton Hamvention. Despite the noisy environment surrounding the booth at the time Bob’s demonstration of the new PRAS absolutely blew me away. The received signal readability went from very painful and difficult copy to pleasant armchair copy with a few quick adjustments on the unit. Pure magic! I absolutely gotta have one of these. Nice going there Bob, you’ve done it again.
73,
Bob, KW4CQ
I operate a TS990 remote. Can I use the PRAS connected to the remote CPU sound card , getting audio from VoIP program ARVP-10R, with expected good results?
Enrique Gil Arranz EA2LY
Magnífico,muy alta calidad para nuestros equipos,inalcanzable para mí…
Magnificent, very high quality for our equipment, unreachable for me …
What about those of us who have different hearing loss in each ear?
Hello Bob,
I have been reading about your PRAS which I think is a very wonderful device. I have worked in the industry (TELCO) and know how important equalization is over long telephone lines for Stereo Audio, Video and Data. Your new device has brought equalization techniques to ham radio – a revolution in the radio amateur hobby. However, I wonder why with most radio amateur transceivers now having two receivers why you have not thought about DUAL PRAS? I believe a dual PRAS certainly would be a great audio enhancing device in light we amateurs receive dual channels many times during communications with others radio stations.
I think your next product should be something similar to this device, but closer to a Symetrix 528 for a transmitter audio pre-processor.
td
HAPPY NEW YEAR!
I sure don’t want to be rude but I’m curious why a two-way amplified speaker when your crossover is at 2khz – 3 khz. You emphasize the crossover sweet spot but then offer only a two-way speaker. I find this unusual. I would think something more like a PreSonus e44. Do you have plans of offering a speaker that can take advantage of the increased mid-range? That would be really nice.
I’m also concerned with stage gain in that I use a West Mountain Radio Clear Speech DSP. They can be rather sensitive on being over driven so the speaker volume going to it needs to be kept within range. I see there’s an analog meter on the left – is this for input, output, or selectable?
Hi Bob
I heard your system at Pacificon. It is amazing, However I previously spent a lot of money on non powered speakers. I would really like to get this equalizer just for headphone use.
I am hope it becomes available that way.
Richard
Can this system be used with a Flex radio stereo output? Has the issue with RF getting into the speaker at transmit been corrected? I really like to purchase one but am concerned about the RF issue.
Thanks
When using headphones is the speaker output muted or is it still active for others to hear?
I purchased the PRAS and HPS-5 to use with my iCOM 7300. I was already happy with the receive audio of the radio. THEN I used the PRAS/HPS-5. OH MY!!!
I’ve never heard “Ham Radio” sound so good, the clarity is fantastic. I can tailor the sound to my ear (I have some of that “presbyaudic” (old ears) hearing loss that Bob mentions in his comments), and it makes a HUGE difference.
Using the Pro7 Headset WITH the PRAS makes a big difference also, again adjusting so it sounds good to MY ear.
Heil hit a HOME RUN with this product, it wasn’t inexpensive, but it was worth every penny!
I’m intrigued by the PRAS. I do have a few questions regarding it’s use with other hardware. Is there any conflict of using a Time wave DSP-599zx in series with the audio chain? Same question regarding leaving the PRAS inline while using amateur radio digital modes thru soundcard? SignalLink USB?
Please send this question to info@heilsound.com