The Infinity Reference X series car speakers have been around for many years, but they consistently perform well. The model we tested, the Infinity 9623ix was among the best performing speakers in our audio quality tests, as well as in our comparative loudness tests. While the series doesn't feature component speakers, it has speakers that fit all the common installation sizes and even several uncommon sizes. However, it's the speakers’ affordable prices that makes the series stand out. When you're trying to balance cost with performance, you should look at the Infinity Reference X series.
To measure audio performance, I recorded each speaker repeatedly playing a 20Hz to 20kHz sine tone. Then I used a frequency analyzing plugin to create a frequency signature of the recorded tone. From this, I graded how accurately the speaker reproduced the low, mid and high frequency ranges. Overall, the 6 x 9-inch Infinity 9623ix received an A-.
It performed the best in the high frequencies, receiving an A+. This is exactly what you want in a speaker, even if you prefer music with fat bass. Your body might feel the music in the lows, but inaccurate highs cause ear fatigue and headaches – they sound grating, and you'll even wince. Only the Alpine Type-S speaker received as high a grade.
The speaker’s midrange accuracy was also very good, receiving an A. It's not perfect, but no speaker is. Its midrange was more accurate than that of nine other speakers we tested, which means it's balanced and detailed. When you pair this with the excellent high-range accuracy, it makes for a good balance of shape and detail in the music you listen to.
The Infinity 9623ix’s low-frequency accuracy wasn’t as impressive, receiving a B-. This isn't terrible – the bass is there, but it starts to wobble around the 300Hz mark. If you pair these speakers with a subwoofer, the sound quality would be about as good as you can expect from car speakers.
The Infinity Reference X’s sensitivity rating is 94 dB. Sensitivity is often pointed to as the most important specification, and it indicates the volume the speaker should create when supplied with 1 watt of power, as measured 1 meter away from the speaker. This is the highest sensitivity rating we saw – only the Polk MM1 and the JBL GTO speakers have as high of a rating.
However, the Infinity Reference X speaker was the only one to back it up in our comparative loudness tests, in which it received an A. Only the Pioneer PRO speaker was better at producing volume. I tested comparative loudness using the same car stereo to power every speaker, and I used a decibel meter to measure the speaker’s volume with the stereo set at 10, 20, 30 and 40. While I don't know how much power is supplied at each of these settings, the 9323ix was among the loudest at every level.
The power-handling ratings are average – its continuous rating is 100 RMS watts and the peak is 300 watts. However, with the speakers being so efficient, the average power handling rating is less of a concern because you don't need as much power to turn it up as with other speakers.
The Infinity Reference X series has all the common speaker sizes: 6 x 9, 6.5 and 5.25 inches. It also features uncommon sizes: 6 x 8 and 3.5 inches. However, it doesn’t include component speakers. That said, component speakers are really only useful for people who want to customize their car audio systems.
The Infinity Reference X series is our value pick because it balances high-end performance and power handling with an affordable price. The Infinity 9623ix’s audio quality was among the best in our tests, and its comparative loudness was second only to the Pioneer PRO. When you consider their low prices, the Reference X speakers are clearly a great purchase.