Introduction

Bookshelf speakers have always been a part of my life either out of necessity, or simply because I am intrigued by the great sound from a small package. I have owned a lot of different small speakers, enough to know that the term “Bookshelf” is often a misnomer.

The JBL Northridge series of speakers is intended to combine the technical performance of JBL studio monitors, at a price point that is within reach of most consumers.

The whole Northridge line has been updated to the series II which makes use of new driver construction. The woofers and midrange drivers are made from the most recent formulation of JBL's PolyPlas™ polymer coated cellulose fiber. This material is intended to provide the sonic neutrality of paper with the added rigidity of the PolyPlas treatment. The combination is intended to give smooth frequency response, with faster transient response, and higher playback levels without distortion. These drivers also use JBL's HeatScape™ motor structure, which improves heat dissipation for accurate performance even during high-volume playback.

The Northridge series uses the same ¾” titanium-laminate-dome tweeter. The tweeters operate using a proprietary waveguide that JBL calls the “Elliptical Oblate Spheroidal™ or EOS™ waveguide. This waveguide is intended to direct sound toward the listening area and away from the side walls for better imaging and a wider sound field. The EOS waveguide is designed to deliver the same response off-axis as it does on-axis.

The Bones

The Northridge N28II is not a small speaker, being 20” tall and weighing more than 20 pounds. It is the top end of the Bookshelf Range in the Northridge line. The N28II uses the same ¾” tweeter as the rest of the line and an 8” mid-woofer. It is crossed over at 4 kHz and uses a flared port to help boost bass frequencies.

The cabinet is a “High Strength, High Density wood enclosure that is braced and damped for minimal vibration”. Simply put, it passes the knock test ok. It is not like smacking a battleship, but it is a decent effort. The cabinet has a black ash vinyl finish that is well done, and it is equipped with good quality five-way binding posts.

The N28II's drivers are video shielded so placement will not affect your TV. The N28II looks very clean and simple with the grille in place. With the grille off, this speaker has a distinctly techno look with the grey tweeters against the black ash finish.

Multi-Channel Sound

I listened to the N28II's for three weeks in both my living room system and in our theater. Fresh out of the box they went into the L&R front positions in our home theater. I turned on a TV channel, shut down the projector, and let them run for a few days to break them in. I was not sure if break in was necessary, but I did it anyway.

My current theater speakers use silk dome tweeters rather than metal. It was a noticeable difference at first. The N28IIs were not necessarily brighter because of the tweeters; they simply were not as lush as the house brand. The difference is understandable, and expected. The Cost of the N28II pair is about a third of the cost of the individual speakers in our surround system, and metal does sound different than silk. It is a preference thing though, not that one is necessarily better than the other.

I was surprised at how well the N28II's blended in with the other speakers in my seven-channel system. With the N28IIs in the same positions as our regular Left and Rights, imaging was very good. Mid and high end detail were precise, and the speakers handled dynamic material without a problem. The whole system was crossed over at 80 Hz for both movies and music. I watched the Godfather series over a three day period, and the fabulous score of these films was delivered carefully with good imaging and localization. Listening levels were maintained in the range of 65 to 85 dB, and there was no indication that the N28IIs were even challenged at this output level.

Next up were the two Terminator films. If the Godfather films are the equivalent of a classic American opera, then the Terminator films are the classic American rock concert. These films are best enjoyed with the volume up. I took this opportunity to push these speakers around a bit and see if they were truly the offspring of JBL's Pro Audio line. The listening levels were in the 85 to 105 dB range, and the N28IIs were able to deliver good imaging without appearing to be weak points in the front array.

While it was apparent that my usual speakers were missing from their normal left and right duty stations, the N28IIs were not disappointing substitutes. It was obvious during the motorcycle chase scene in T2, as the exhaust tone of Arnold's Harley panned back and forth across the screen, that there were different speakers on the left and right than in the center. In this situation it is important to keep in mind that I was quite focused on the speakers. These are films that I am very familiar with and they have tremendously busy scenes that would not usually draw attention to this sort of subtle difference in sound. It also points out the necessity of staying with the same brand and models across the front, when possible.

A surround system making use of five or six N28IIs combined with a subwoofer would make a very capable theater audio system. The N28II's did a yeoman's job in the theater for the rest of the week. They were fed a steady diet of typical family programming without anyone else even noticing that there was a new set of speakers in the room. Once I took the grilles off, they finally noticed the different look of the silver trim panels and it was pointed out that “We had some cool new speakers” in the media room. I would say that comment was an affirmation of the target market for the styling of this product.

I did experiment with running these speakers without a center channel, and then without the surrounds, while still watching images on the display. The N28IIs with only a subwoofer added produced a respectable soundstage, and were able to properly locate dialogue on our 92” x 52” screen without drawing attention to themselves. This would support the design concept of the EOS™ waveguide. I am an engineer, and I had to look up the word "Oblate", which by the way means flattened or depressed at the poles.

Two-Channel Audio

The next stop for N28IIs was the living room and onto a pair of 30” tall Target stands. If you choose to use speakers this size on stands it is really important to secure them. If they fell on a child, or on your foot for that matter, it would be unpleasant. The family cat or small dog would not appreciate it either.

Run as a stereo pair full range, these speakers were capable and accurate performers. Bass-heavy material above 80 dB challenged the N28IIs which makes sense for a mid-level bookshelf speaker. These are not your father's “Rap Master Daddy” speakers, but then neither are most of the other speakers this size, or at this price point. If you want big bass, then you will have to pair them with a sub.

I started out with Buddy Guy's spirited live recording “The Real Deal”. Buddy is backed by G.E. Smith and the band from Saturday Night Live. This is the sort of material that the N28II handles well. The music is showcasing the fantastic guitar work of one of the very best blues guitar players of our era. The N28II's handled this music with aplomb. It was fun to push them to sound levels that were quite high, without distorting the message that was speaking from Buddy's guitar.

Then came "Seven Come Eleven" from the Lionel Hampton and Friends Telarc CD. The vibes are one of my favorite instruments. On this recording they are being touched by the one person most responsible for my attraction to this instrument. I was expecting to find flaws with the N28II's here. I thought the velvety smooth sound of the vibraphone was going to have some edge to it, some of the cream skimmed off. Surprisingly, while the N28 seemed a bit bright, it was not the first thing that I noticed when the song began to play. The vibes were sounding just fine, and I wound up listening to the whole disc.

Erykah Badu's debut CD "Baduisim" was the last challenge for the JBLs. This is a taxing low end piece for most systems. Erykah's honey sweet voice was no problem for the N28IIs. She sounded clear and articulate, her voice taunting and scolding. But, the weak point of this speaker was finally showing itself. The bottom end was simply too much low end information for this speaker to reproduce at significant sound levels (above 80 db). The deep bass simply got overwhelming.

On the Bench (JEJ)

At 50 Hz and 100 dB, the THD was quite respectable at 1 1/2%.

Again, good results at 100 Hz.

With 2% THD at 1 kHz, the woofer is being pushed to its frequency limitations.

IMD levels, at $399 per pair, are satisfactory.

Now we are into the tweeter's range of output. The second harmonic is a littler larger than the third, which is good.

IMD levels at mid-band are good.

The frequency response shows a significant peak at 3.6 kHz. It may be that JBL designed this into the speaker to give it some snap for the young consumer who is likely to buy this speaker and use it to play Rap and Heavy Metal. There is also a bump at the top end of the audible spectrum.

The impedance has a couple of spikes, and in general, should be an easy speaker to drive. Good thing, since it will likely be connected to a mass market receiver.

Conclusions

JBL has made an effort to combine the dynamic range of their highly regarded Pro Audio Line into a product that provides exceptional value. They have done a good job of addressing performance for a wide range of musical tastes, which makes the Northridge N28II a good choice. Whether you are looking for a first pair of speakers for your dorm room, or a reasonably priced surround system, these are well worth consideration.

 

- Brett Johnson -

 

Related to the article above, we recommend the following: Primer - Speakers

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