Infinity Primus 5.1 Speaker System October, 2003 Brett Johnson


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Primus 360


One 3/4" Tweeter, Two 5 1/4" Woofers

MFR: 38 Hz - 20 kHz ± 3 dB

Nominal Impedance: 8 Ohms

Sensitivity: 93 dB/w/m

Size: 39" H x 8 1/4" W x 13" D

Weight: 48.5 Pounds Each

MSRP: $329 Each



Primus C25


One 3/4" Tweeter, Two 5 1/4" Woofers

MFR: 80 Hz - 20 kHz ± 3 dB

Nominal Impedance: 8 Ohms

Sensitivity: 90 dB/w/m

Size: 7 5/8" H x 17 1/2" W x 9 5/8" D

Weight: 17.6 Pounds Each

MSRP: $199 Each



Primus 150


One 3/4" Tweeter, One 5 1/4" Woofer

MFR: 58 Hz - 20 kHz ± 3 dB

Nominal Impedance: 8 Ohms

Sensitivity: 88 dB/w/m

Size: 12 3/4" H x 7 3/8" W x 10 1/2" D

Weight: 13.5 Pounds Each

MSRP: $99 Each



PS-12 Subwoofer


One 12" Driver

MFR: 25 Hz - 150 kHz ± 3 dB

50 Hz  - 150 Hz Variable Low-Pass

Size: 16 1/2" H x 14 3/8" W x 17 1/2" D

Weight: 45 Pounds

MSRP: $499



Infinity Speakers  


So there they were. Six boxes in a huge pile sitting on my front porch, basically the size of a refrigerator. It was a complete set of Infinity Primus series speakers in for review. My UPS guy is going to quit coming down my road soon and just start leaving the yellow notes, so he doesn’t have to schlep all the stuff up my driveway to the porch.

Infinity conjures up a wide variety of images, from the present and from the past. I remember the first Infinity component system that I listened to. It was a huge system with large arrays of tweeters and midrange speakers accompanied by two of the biggest subwoofer enclosures I had ever seen. It was all housed in beautifully finished cabinetry, and cost upwards of $20K. Impact was the key; it was the you-are-there sound of the early eighties.

Now Infinity is bringing that level of quality to many of the consumers who would appreciate the quality associated with the brand, but are not in a position to afford the higher end models the brand is best known for. Enter the Primus line. Primus brings the big sound of Infinity to your theater in quality conscious, cost effective speakers that do their job well.

From the Technical Point of View

The infinity Primus series includes six loudspeakers with two floor standing versions, one MTM center channel, and three smaller monitors for stand or wall/bookshelf mounting.

For this review, we had a pair of Primus 360 Floor-Standing Speakers, a Primus C25 Center Channel Speaker, a pair of Primus 150 Bookshelf Speakers, and the PS-12 Subwoofer. There are three subwoofers, including the small PS-8, the mid-sized PS-10, and the larger PS-12 which I used in this review. (The subwoofers are not part of the Primus series.)

All of the speakers are intended to be “voice matched”, and are finished identically, so they can be used in any combination to create a system. The 150 has key-hole brackets for wall mounting. The 140 has threaded inserts to accept aftermarket mounting systems.

The Primus line of speakers use an aluminum cone driver called the “Metal Matrix Diaphragm” (MMD). Metal matrix refers to the ceramic coating on both sides of the aluminum cone. This is intended to reduce distortion and cone breakup by providing a very rigid low mass driver.

The combination of drivers and cabinet construction are optimized to reduce internal resonances and achieve optimum sonic performance. The line is intended to be “room friendly”, making use of a specially shaped waveguide for the tweeter. Infinity expects the Primus series to provide “precise imaging, even frequency response, and controlled directivity over a wide listening area”. The Primus line seems to be very efficient with the 360 @ 93 dB, the C25 @ 90 dB. The smaller 150 is less so @ 88 dB, but it can be attributed to the driver compliment of only one tweeter and a 5.25” woofer.

All of the speakers have a single pair of five-way, gold plated, all metal binding posts. They will accept bare wire, spades, or banana style terminations (the plastic safety plugs for European consumers were easy to remove). They are all finished in a black ash which is very simple, and use black grilles. The speakers look subtle with the grilles on, and are eye-catching with the grilles off. The front baffle is trimmed with silver, and the contrasting black and silver of the driver cones gives the speaker a very technical look. The contrast in appearance should satisfy a wide range of appetites in the constant battle for décor in the theater space.

The PS-12 subwoofer is included in this system. It is the largest of the PS series, making use of a 12” MMD driver and a ported enclosure. The PS-12 has a 300 watt amplifier with a variable crossover, phase switch, and an adjustable level control. The subwoofer can be driven with either line-level or speaker-level inputs. The controls and the port are on the rear of the cabinet, and the driver is front firing. The enclosure is also finished in black ash and will blend nicely with the rest of the Primus line.

There is no misconception about the purpose of the Primus speakers. The fit and finish are acceptable by any standard. They are intended to provide value based on sound quality, rather than impact as furniture, or some sort of deco sculpture. They do not have the unique structure of the Intermezzo series for example. But that is not their targeted market either. The Primus series is a speaker that will satisfy the needs of a wide range of mid-level audio consumers. They work really well as a stereo pair for the “Let her rip Rock and Roll” crowd, and they also will give you a lot of dynamic range for your home theater. I found the 360 to be very capable both with and without the subwoofer.

The Primus speakers were delivered to me as a package, so I got on with setting things up as a traditional 5.1 surround system. I have a pair of 36” Target Stands that I put the 150s on. They have brackets on the back for wall mounting, but I chose to use the stands so we had more flexibility in location. The 150s were located to the sides and just behind seating area, 2100 and 3200 degrees respectively from the center seat.

Our listening room is our theater, and we had the room designed and engineered specifically for the purpose. The wall around the screen is made up of acoustically transparent panels that keep our speakers out of sight and out of range of the children. I chose to place the Primus 360s in front of these panels, bringing them 28” from the front wall and 24” in from the side walls of the room. The Primus 25 center channel was placed on the angled shelf above the screen. The shelf is angled to allow the tweeter to be aimed at the seating area of the room and is made of 1” MDF glued and screwed to the superstructure of the screen wall. We used the checkpoint laser system when we built the room to get this shelf properly located. If you find yourself in the same situation, a string line can be used to get the angle correct.

The location of the center channel is how the room was designed. We were not able to use a perforated screen so that we could place the center channel directly behind the screen as our designer Dennis Erskine had suggested. The speaker above the screen was the compromise. I have never been disappointed with this location. The topic of center channel speaker location is always one that will produce a lot of very strong opinions. I chose to stick with Dennis’s advice and it was a good choice.

I pulled one of my own subs out of the front left corner of the room and put the PS-12 in its place. There was about 4” of space around both sides and the rear of the cabinet. The corner is treated with 3” of Knauf sound shield material over the sheetrock and MDF structure. The balance of the airspace is taken up by abundant quantities of Dacron batting to dampen things evenly.


I used an SPL meter and my processor's test tones to set the system levels. I then took a heretical action and set all of the crossover points to 80 Hz. This is one of the other issues that everyone has an opinion about, and I have developed mine carefully. (Imagine the shock as my purist friends discovered that I had my B&W 802s crossed over, sending their “chubby” bass to my subwoofer during movies). When I want to do stereo listening, I set my processor to pass through and do it. Most of the time, we are using our theater as a multi-channel system with all of the speakers set to "Small".

With the speakers set up, I spent a few days in my usual routine of system use. I get up in the morning with my son, and we watch "Dora the Explorer" and a few other animation shows. I watch the morning news with my wife, and we open the theater doors and use the audio system for background music during the day. The Primus speakers were running for about a week as daily entertainment before I sat down for some critical listening. I think that the idea of break-in is for both the speaker and the listener. In this case, we were changing our system from a 7.1 channel system using four dipole surrounds and two subs to a 5.1 system using direct radiators for the rear channels and one much smaller sub. I thought that it was just as important for us to get used to the system as it was to stretch out all of the diaphragms and allow for full dielectric absorption in all of the conductors (for the EEs and the Break In Police).

I try to do most of my evaluations using material that I am very familiar with. I use the David Chesky "Ultimate Surround Sampler" often because it has a good variety of well recorded music. I am very fond of most of the selections, and the ones that I don’t choose to listen to regularly are fine examples of their genre. The other thing that I do is listen at levels that are usually the same regardless of the equipment that I am evaluating. I try to stay in the range of 70-75 dB, and I use my SPL meter constantly to do this

I use a number of Chesky recordings for my reviews and had the fortunate experience of meeting David Chesky at the San Francisco Hi-Fi show in June, 2003. He took the time to explain his ideas for all of the different methods of producing audio software. I think that as challenging as it is for consumers to understand the direction we are heading, Chesky was able to convey his feelings about the difficult environment for content producers, without lamenting the formats that we have to chose from. I was able to spend a few moments talking with him about his ideas for our industry going forward, and it was really a treat to hear the perspective of someone who is a content producer at heart. I felt the same way about a number of people that I met at the show. Ray Kimber (Kimber Kable), Richard Schram (Parasound), Rich Moore (WBT), James Tanner (Bryston) and Bharath Rajagopalan (Texas Instruments), were just a few of the people that I got to have serious, engaging conversations with. I was really glad that I had the time to run down there for a couple of days and take part.

The Primus 360s held their own in the stereo mode as full-range transducers, only struggling with the very lowest frequencies of the two-channel version of "Entre Amigos", a wonderful David Chesky recording featuring Rosa Pasoa and Bassist Ron Carter, with classic Latin acoustic accompaniment.

With the PS-12 sub in the system, the 360s were at ease with a wide variety of program material. With stereo, they were dynamic and precise, and the 360 is a capable stand-alone speaker. As part of a surround system the 360s would certainly be the anchors of the soundstage, blending well with the center and surrounds in spite of the difference in the driver size and orientation.

I did a bit more listening to the system as a stereo pair throwing in "Green Day", and the Starbucks “Artists Favorites of Sheryl Crowe”. The Primus 360s with the sub crossed over at 80 Hz in my processor, and the speakers selected as Small, sounded great. The very dynamic music of Green Day uses the rumbling rolling bass line that made the mosh pit a fond part of my past. Track 4 "Longview" is my favorite, forcing me to leap around the room with my 4 year old and our dog (without, I must add “Pulling a Hammie” or sending the son or the dog to the hospital). The Sheryl Crowe disc is full of favorite songs that were all well recorded and came through the Primus system with the feeling and sound that they had the first time I heard them.

The next step was to throw in the "Ultimate Surround Sampler" and listen to a few tracks of multi-channel music. Track 3 is an acapella recording of "Eight Days a Week" by the Persuasions, which has truly wonderful range. The baritone bass line was touching, and it felt like it was coming from the front left of my room. The voices were clear, as were the sounds that the singers were making while breathing and moving on the stage. The drumming on the next cut, "Tumbao de Tamborito" by the Conga Kings, was snappy and filled the room the room with congas. The drumming builds as it follows the saxophone through the horns' range and then takes over as the sax drops out of the mix. The flatness of the cow bell is intentional, and it comes off that way. This track brought out the good midrange performance of the Primus speaker package.

As the Primus speakers use metal drivers, I was expecting them to have good transient response. I was also bracing myself for a sound that was not the same as my paper coned, silk domed, Vifa driver house brand. I was guilty of preconception, but completely willing to admit it.

I was a bit surprised at how little of that harshness came through. The Primus line sounded better than I had expected. I felt like moving on to some other material and threw in a DVD of "David Gilmore Live at Robert Wyatt’s Meltdown" concert. I am a Pink Floyd fan. I am also a David Gilmore fan. I have seen them in concert together with Roger and without. I have been patiently waiting for the "Delicate Sound of Thunder" (DSOT) to be released on DVD since the format came out. I was able to see the concert on laserdisc a few years back, and I am still waiting for the DVD. There were parts of the performance on the video that are not on the CD. The visual performance combined with the sound has always been one of my favorite concert performances.

This DVD will hold me over until they give us the DSOT on DVD. My only complaint is the severity of the aging process that occurred when I realized, looking at Gilmore and Dick Perry racking out “Shine on You Crazy Diamond”, that I hadn’t aged any less than they had. Dressed in a faded 2XL T-shirt, comfortable jeans, and shoes to match, Gilmore still was able to remind me of my youth with only a few notes on his acoustic guitar. The video quality of this disc is not remarkable. The audio quality is very good in my opinion, and the combination makes the content, as a result, exceptional.

The thing that I have found to be most important to me when it comes to enjoying multi-channel music, either with or without the visual performance, is that it is microphoned properly. I have developed this opinion over time. I like being in the audience, not behind the band, or over the band, or in the middle of the band. The picture can occasionally pan for effect, but the soundstage needs to be on the stage and mostly up in the front of the room.

I like this DVD for this reason. The performance of the Primus system, particularly the front channels, made me a part of this concert. Rather than bringing the music into the room, I felt like a part of the performance. These were songs that in most cases I have listened to hundreds of times, "So you think you can tell heaven from hell” was making my skin tingle, just like it had every other time. Acoustic instruments are becoming my favorite way to hear a lot of music; they were reproduced faithfully by the combination of the Primus 360s and the C25 center.

The halting voice on the intro narrative for "Comfortably Numb", was feeble, and projected the image of the person reciting it in a way that made you feel him, sitting there in his wheel chair. I could not resist the need to push this system on the ensuing guitar solo. Gilmore sets down the acoustic, while the cello player carries the chorus, picks up the “Ax” and starts swinging. A steady 95 dB highlighted the Primus 360's ability to rock, and Gilmore is still adept at making the guitar sing. The low neck work on the guitar also gave the high frequency part of this system some work that did not disappoint.

I have to also give credit to the PS-12 subwoofer. I did not expect it to have the oomph! that it did. It was a noticeable change from two sealed Tempest subs that I normally run. I did not do any tests to verify actual frequency response or the output of the sub by itself, but throughout my actual listening evaluation, it held up very well. I pushed the whole system up into 105 dB peaks, and things stayed orderly until the music got very challenging. The reality of the price point showed itself when the output was high and the music was equally dynamic. The Primus is a capable system, but it is possible to abuse it without intending to.

Acceptable performance on music usually means acceptable performance on movies. With that in mind, I felt like pushing a few Gs through the system with the action film "Behind Enemy Lines". I have been using this as an evaluation piece since it came out. A friend, who actually flew combat aircraft, told me that he thought the missile scene was one of the best renditions of fighter plane flying that he had ever seen. (He also said that the SAMs would not have been so tenacious.) He has watched this in my theater at least twenty times, and every time he is noticeably affected. From the time the music starts on the flyby of the carriers’ bow, until their parachutes open, you are locked into the cockpit of the aircraft with the pilots.

The bulk of the work is done on screen and in the front of the room. The weakness of this platform did begin to show a bit though, in the surround speakers. I have no doubt that the 150s are capable little speakers. They just did not seem to fill in the blanks as well as I would have hoped when the action moved off screen. While I think that the direct radiator was good for the music video, the rushing pans of an action film may have been too demanding. I thought that it might be the film and that I had become too accustomed to my own system. I pulled out "The Phantom Menace and cued up the Pod Race.

I grabbed the most unbiased non partisan person I could find, my wife Dee, and had her sit down to watch the scene with me. (She knew that I was reviewing speakers, but not the type or manufacturer.) She has watched the scene a few times, so she knew what was coming. The results were the same for her that they were for me, something was missing.

I took the next step and raised the 150s up 24 inches for a total height of 5 feet off the floor. This helped with filling in the sound field a bit during heavy pans, but it did not make things blend as well as I had hoped.

I finally wall mounted the Primus 150s using the keyhole mounts, 7 feet off the floor and 2 feet from the upper soffit that surrounds my room. Surprisingly this was the best location of all, and I think it was reflection off of the soffit that helped the 150s blend into the sound field.

I think that for me this was more about dipoles being right for surround speakers than the 150 being wrong. But it was a noticeable difference that was not a critical factor with music, but was for movies. This is particularly so for the big action films that utilize a lot of surround activity. It would be interesting to do a review of a system using four of the 150s for surround duty. I took the 150s out of the system and listened to them as a stereo pair, on the stands in the theater, and in place of my Met 7s in my office. They are capable bookshelf speakers, they sound good, and at their price point they are a good value.

The price point might even make seven of the 360s a realistic option for a very capable full-range theater system and multi-channel audio system. This would surprise a few people when you come clean about what a value they were. They would also eliminate the need for bass management. You could probably justify the cost based on simplicity alone.


The Infinity Primus series speakers are going to be a good stop on the High Fidelity path for a lot of people. The 360 in particular could start in your system and end up in your kids' system ten years down the road (Daddy needs the Intermezzo). The PS-12 is also a very good value, and the combination of speakers works well together. The only thing that I would do differently would be to get more of the 150s, or choose one of the larger speakers for surround duty to match up with the 360s better.

- Brett Johnson -

I used the following equipment during the evaluation of the Infinity Primus speakers:

B&K AVR 307
B&K ST-140
B&K ST-60
Panasonic RP-82
Panasonic TUHDS-20
Marantz LV-520
Canare’ Star Quad 4SG11 Speaker cables
Canare’ RG-6 interconnects
WBT Terminations (Spades and Banana Plugs)
Innovative Technology Transient Suppression


© Copyright 2003 Secrets of Home Theater & High Fidelity

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