KLIPSCH HERITAGE

Forte IV Loudspeakers Review

THE HIGH NOTES

• Built on Tradition
• Let It Rock
• Proudly Crafted in the USA

Company & Product Overview

The year 2021 is going to be very special to the folks at Klipsch as it represents their 75th anniversary. In 1946, Paul Klipsch sold his first speaker out of a small tin shed in Hope, Arkansas, and launched what has become one of the world’s most popular speaker brands ever. Back then, Paul enlisted the help of a local cabinet maker and the Baldwin Piano Company to produce the first few speakers, before hiring his first full-time employee. Today, that original location is the home to the Klipsch museum, and Klipsch employs hundreds of music-loving people while being sold all over the globe.

Paul Klipsch believed in 4 design principles that lead to his first speaker, the Klipschorn. Those are high efficiency, low distortion, controlled directivity, and flat frequency response. Every Klipsch speaker made today still adheres to those same guiding principles and if you ever visit their headquarters in Indianapolis, you’ll see them everywhere!

To celebrate the 70th anniversary of Klipsch and due to huge demand from their fans, Klipsch introduced their Heritage series in 2016. The Heritage models brought back new and improved versions of most of the original Paul Klipsch designs and made Klipsch fans all over the world very happy! The Forte III was added to the Heritage lineup in 2017.

Design & Build Quality

Most of the early Klipsch speakers were known for being quite large in physical size as it does take a large cabinet to have a complete horn-loaded design. The Forte was introduced in 1985 and was a great way to get that classic Klipsch sound in a much smaller cabinet. The Forte went on to become one of the most popular Klipsch speakers ever made but was discontinued just five years later in 1989.

When you look at a Forte next to the top of the line Klipschorn, there is no question, it is far easier to fit into a room than the Klipschorn, La Scala, or Cornwall. Those models have quite an imposing footprint with big sound to go along with their large size.

Even though the Forte stands at 3’ tall, the ratio of its dimensions (only 13” deep and about 17” wide) gives it a smaller look that enables it to fit into most living rooms. We think it is the best value in the Heritage series as it too can sound very big and powerful, yet can blend into a space far easier. Just make sure and have some help around for your new pair as they are 72 pounds each out of the box!

You have four choices of finish on the Forte IV with grills designed to match each one. They are American Walnut with Salt and Pepper Grille Cloth, Natural Cherry with Salt and Pepper Grille Cloth, Black Ash with Salt and Pepper Grille Cloth, and Distressed Oak with Lambswool grille cloth. Our favorite is the Oak with the light-colored grill as it just has this classic retro look we feel is fitting for a speaker with a 75-year heritage.

All of the Heritage series models are made in the USA at their Hope, Arkansas factory. There, skilled craftsmen, who in some cases have been with Klipsch for decades, make each and every Heritage model by hand. Each pair is serial number matched just like the book-matched real wood veneers that grace the speaker cabinets. A pair of speakers even travels together through the factory to assure you get a beautifully matched pair of speakers. You can rest assured, a Klipsch Heritage speaker will last a lifetime and be something your next generation will likely enjoy as well.

Features & Technology

The Klipsch Forte IV is a 3-way design with a horn-loaded tweeter, horn-loaded midrange, and 12” woofer on the front of the cabinet. The rear has a 15” passive radiator.

The Forte IV is rated at a 99dB sensitivity which makes it a super-efficient speaker. You can drive these with anything from a tiny tube amp to a big McIntosh or Mark Levinson solid-state amp with no issues. With the ability to output an SPL level of 116dB, these can rock!

Starting with the tweeter, the Forte IV uses a titanium compression diaphragm driver coupled to a patented Klipsch horn. All tweeters like to beam as the frequencies increase. Klipsch has updated the phase plug to improve the linearity of the high frequencies. In effect, it ensures controlled uniform directivity all the way up to the high frequencies. This has a dramatic positive effect on sound staging.

The midrange compression driver is a new model using a polyimide diaphragm. This driver was developed for the recent Cornwall IV. We were curious as to what exactly a polyimide was and did a little digging. It turns out to be a pretty exotic plastic polymer that has a very high resistance to heat. Polyimide is used in high-tech military applications and high-temperature fuel cells. The midrange driver is coupled to a modified Tractrix® horn. The horn uses Klipsch’s patented Mumps tech which gives you extremely even sound in the listening area.

The 12” woofer is made of a fiber composite cone material. To extend the bass even deeper, Klipsch adds a rear-mounted 15” sub-bass passive radiator. Passive radiators enhance the bass from the active woofer. The Forte IV gets down to 38Hz. We also love the solid binding posts on the rear that are big enough from some massive speaker cables and are set up for bi-wiring if you wish.

Klipsch decided to voice the new Forte IV more like their top-of-the-line Klipschorn and La Scala speakers. These use a steeper slope than the other models and is used in the Forte IV. They also upgraded the quality of the components used in the crossover. While you never see a speaker crossover, it is a critical link in the chain as it splits up the incoming signal and sends different frequencies out to the drivers. A cheap or poorly designed crossover can ruin the sound of a speaker. From the tech used in this new crossover network, it appears to be first class.

As you might expect from a Heritage series Klipsch, the cabinet is very solidly built, in the case of the Forte IV it is made of ¾” MDF, then the matched veneers are applied.

Technical Differences in the Forte III and Forte IV

We love the fact that Klipsch, like just a small handful of other speaker manufacturers who actually make their own speaker drivers, spells out the actual driver name they use for the speaker components. This makes it easier to compare model to model and to see what they have changed when a model is upgraded.

Tweeter
Both the Forte III and Forte IV use the K-100-TI 1” titanium diaphragm compression driver on a K-79T horn. The phase plug was changed on the Forte IV for more linear high-frequency dispersion.

Midrange
This is where there are some big changes as the new Forte IV uses the same compression driver developed for the more expensive Cornwall IV. The driver is the K-702 model while on the Forte III they use the K-70 model that uses a titanium diaphragm as compared to the polyimide material on the K-702 version. We should point out Klipsch also uses polyimide for the tweeter diaphragm in the La Scala and Klipschorn. Both the Forte III and Forte IV use the same K-703-M horn.

Woofer and Passive Radiator
These are both identical on the Forte III and Forte IV.

Crossover Network
Klipsch made some big changes here, using both more expensive components in the crossover network and changing the slope to more closely match what they do in the La Scala and Klipschorn. The crossover points remain the same at 5.2kH and 650Hz. It appears the goal was to get the sound of the Forte IV to be closer to a Klipschorn!

Cabinet
While the Forte IV is ¼” shorter in height than the Forte III, this is due to the redesign of the base the speaker sits on. All new Forte IV color versions have the same matte black base.

Performance Testing and Comparison

We set the Forte IV and Forte III up in our listening room to test the Forte IV and how it compares to the Forte III. We did an asymmetrical set up so each speaker would be the same distance apart and in our rectangular room would be just a mirror image on distances from the side walls.

We pulled them off the wall about 25” and used a tape measure to get them exactly the same for both models. To power them we used a McIntosh stack consisting of their MT5 turntable, C-49 preamp, MC152, and MCD350 CD Player.

It is always important when comparing things to perfectly match levels, which was a cinch with these two as they are identical in sensitivity.

We decided to make this an all-analog comparison and pulled out some classic records from years gone by, which of course plays right into the legacy behind the Forte. For our testing, we listened to one of our all-time favorites the Getz/Gilberto with The Girl from Ipanema, the Amanda McBroom Dreaming Album, a very old Direct-Disk of the Neophonic String band, and finally the Persuasions No Frills album.

You probably noticed a focus on midrange here, which is where we expected to hear most of the improvements in the new Forte IV. First, it is totally clear the Forte IV is an evolution of the Forte III. The sound profile between the two is similar, but the differences we heard were pretty big to our ears.

On the Getz/Gilberto we heard a big difference in just how much more effortless the voices and saxophone sounded on the Forte IV. When we flipped back to the Forte III, they almost sounded strained.

The title cut Dreaming was even bigger. Her voice floated in space and sounded very natural on the Forte IV, and when we switched back and forth to the Forte III, we felt her voice had almost a coloration to it. We actually had to do a double-take and pull the grills off to make sure the horn itself was not different on the two as it sounded like we were hearing some horn resonance on the Forte III in comparison. Our theory is the new midrange driver and steeper crossover slopes are a much better match to the horn itself.

Next up were the Persuasions, who are an acapella group, and we heard the same differences in the midrange improvement but even more so with multiple voices going on.

On every single cut we had tried up to this point, the stereo image was also wider, deeper, and more precise in space on the Forte IV. But when we switched to the next album, that difference became huge.

The Neophonic String Band is a great old bluegrass record. On the Forte IV, everything was perfectly in space, spread out very well. When we switched back to the Forte III, it was like the image just went back into the two speakers.

Needless to say, we were very impressed with the new Forte IV. We did not even cover here how both models have great bass impact and have such a high sensitivity, you can run them with a very small amp.

We have to give Klipsch some kudos for taking a speaker that was already really good and making it much better in our opinion.

Proudly Crafted in the USA

Own part of a legacy from the craftsmen at Hope, Arkansas with the Forte IV. From book-matched veneers to meticulous hand assembly, these are made with pride by people who have been making heirloom speakers for decades.