JBL Synthesis 4305P Studio Monitor (Pair)

Company & Product Overview

Just about every fan of live music has heard the great sound of JBL speakers at a concert event. Their professional music systems have been the go-to choice all over the world since the Grateful Dead made them famous in the early 70s with their Wall of Sound which had almost 600 JBL speakers driven by 48 McIntosh amplifiers. They are still the top choice for the pro sound market and recording engineers and also offer a huge variety of speakers for consumers from portable speakers to high-performance audio models.

Over the last several years we have seen a big trend of people wanting great sound but with fewer components. Powered speakers that have everything built into them to give you music have become extremely popular, especially for desktop computer use. Most of the market for powered speakers is found in the sub $500 a pair category, but in the past few years, some powered speakers have emerged that rival high-performance separate audio systems.

For a large group of people, these powered speakers are an outstanding solution as you only need a pair of speakers and possibly a turntable. JBL has several very highly regarded powered speakers that are used in the professional production world. As a matter of fact, you’ll find their 705p and 708p at some of the top movie soundtrack post-production companies where accuracy is so important.

We wondered when JBL would take all of the great tech in their professional powered speakers and add in features that would make them perfect for home use. We are happy to say the new JBL 4305P Powered Bookshelf Speakers are precisely this product!

Design and Build Quality

Powered speakers have a few really big inherent design advantages. First, when a company goes to make a speaker, they have no idea what type of amplifier it will be connected to and have to be sure it will be compatible with a wide range of amplifiers. And the same holds true for the amplifier or the amps in your receiver. The engineers have to make them able to drive a wide variety of speakers. With a powered speaker, the whole system works as a unit. The engineers know exactly what is going on with both the speaker components and the amplifier and can design them to work perfectly together.

Some powered speakers can take things even further by giving you a separate amplifier for each speaker driver. This removes the passive crossover that would normally be in a regular speaker and does the crossover using active electronics, which is a far superior way to do a crossover as there is no loss in the passive network.

Finally, if the speaker company has some good knowledge of active designs, they can use equalization to perfect the sound coming from each individual speaker. The new JBL 4305P, as you might have guessed, uses all three of these pieces of technology.

They have a 125-watt amp for each of the woofers and a 25-watt amp for each of the high-frequency compression drivers.

From a physical design standpoint, the 4305P looks almost like a normal speaker except for the small controls on the front panel of one of the units. They are very compact at only about 13” tall by 8” wide, by 9” deep and come in a walnut or black wood veneer. As with most of their high-performance speakers, the beautiful (at least to us) compression driver is exposed and the grill hides the woofer. The grill will be JBL blue with the walnut and black with the black finish. Each speaker weighs almost 15 pounds.

The main speaker has all of the connections on the rear. One small caveat, but it is a performance enhancement, is for best performance you want to connect the two speakers together with an ethernet cable. Many powered speakers communicate with each other wirelessly, but JBL felt the sound was better if they were hard-wired like this and there is no length limit on the cable. You can use them wirelessly if necessary but you will lose a little resolution.

Features and Technology

JBL engineers some of the best speaker drivers in the world and a couple of those are present in the 4305P. We love the way they also call out their driver models. Unlike a lot of speaker companies, JBL engineers and manufacturers all of their own components. The compression driver is their new 2410-H coupled with their HDI horn. We could write an entire article on the advantages of a well-executed compression driver, but in a nutshell, imagine a water hose without a nozzle and your thumb over the end and one with a high-pressure nozzle. The latter one has a controlled and long-focused spray, while the other goes everywhere. The controlled directivity means there is less interaction with the surrounding walls which eliminates reflections that blur the sound.

Horn loaded speakers are looked down upon by some groups of audiophiles as there have been designs over the years that were very edgy and too bright which made them hard to listen to. JBL compression drivers are the exact opposite, as they are super sweet yet very fast.

The woofer is the 5.25” JW130P-4 which even has a cast basket for more rigidity. The internal Digital to Analog Converters are all 24bit/192k high-performance DACs. You’ll get a whole slew of connection options with the 4305P. You can tell that JBL, and rightly so, thinks these will be popular for professional monitoring as there are a pair of combination XLR and ¼” phono plug inputs. In addition, you get a 3.5mm analog input, a Toslink digital input, and an asynchronous USB input for use with computer audio. Google Chromecast, Apple AirPlay2, and Bluetooth give you a great set of ways to stream music to them. You also get the Harman Music for Life app which will make streaming or accessing files on your network a snap. They even have a nice little handheld remote for input selection and volume control. Or you can just use the front panel as well.

You can place the speaker with all the connections on either the left or the right side as there is a switch to select which channel the speaker with the connections should be. They also have a boundary control which will reduce the deep bass output if they are close to walls.

The 4305P will also be Roon Ready for those of you who are fans of Roon for Hi-Res music streaming.

We do wish they had come with an HDMI ARC connection. This would have made operation with a TV system more seamless, but with the way these guys sound, we can’t get everything and you can connect most TVs using an optical connection which they have!

One very cool feature is the way they did the subwoofer out. When you plug a cable into the output jack, it engages a high pass filter at 80Hz on the main speaker. This will roll the bass out of the 4305P and let the sub do all the deep bass work.