Alpine KTX-CSP1 Review: The OPTIM8 and OPTIM6 Measurement Mic Explained
Updated: Oct 6
The Alpine KTX-CSP1 is a measurement microphone kit that Alpine lists for two of its OPTIM sound processors, the OPTIM8 (PXE-C80-88) and the OPTIM6 (PXE-C60-60). It pairs a calibrated omnidirectional microphone, rated from 18 Hz to 20 kHz within ±0.5 dB, with a 1.8 m cable and a gold-plated 3.5 mm TRRS plug, and Alpine Australia identifies it as a Dayton Audio kit. Its Indian MRP is ₹10,999. It is for owners of an OPTIM processor who want accurate, repeatable measurements, especially when tuning with Alpine's PC software. You can order it from our Alpine KTX-CSP1 product page.
Key takeaways
Alpine lists it only for the OPTIM8 (PXE-C80-88) and OPTIM6 (PXE-C60-60), not for the PXE processors we sell, such as the R80-8 or R100-8.
Alpine's OPTIM8 launch release names this microphone as the external mic for PC use (sold separately), while it describes the iPhone app using the iPhone's built-in mic.
It is calibrated to within ±0.5 dB from 18 Hz to 20 kHz, and the 1.8 m cable lets you move it around the cabin during measurements.
We found no owner reviews of the kit itself; OPTIM owners' reports are mixed, and they are about the processor.
Alpine KTX-CSP1 specifications
Specification | Alpine KTX-CSP1 |
|---|---|
Type | Measurement microphone kit (Dayton Audio, per Alpine Australia) |
Listed for | OPTIM8 (PXE-C80-88) and OPTIM6 (PXE-C60-60) |
Capsule and pattern | Precision 6 mm electret condenser, omnidirectional |
Frequency response | 18 Hz to 20 kHz, ±0.5 dB (calibrated) |
Sensitivity | 10 mV/Pa (-40 dBV) at 1 kHz |
Impedance | 200 Ω |
Maximum SPL | 127 dB (1% THD at 1 kHz) |
Signal-to-noise ratio | 70 dB (A-weighted) |
Connector | Gold-plated 3.5 mm TRRS |
In the kit | Microphone and 1.8 m (6 ft) aux cable |
Weight | 7.6 g |
India MRP | ₹10,999 |
Figures come from Alpine USA's KTX-CSP1 page and Alpine Australia's KTX-CSP1 page, with the MRP from our June 2026 Indian price list. Our listing matches Alpine's figures.
What the KTX-CSP1 does
Automatic tuning works by playing test signals through the speakers and measuring what arrives at the seats. The processor then sets its EQ to flatten the peaks and dips the cabin creates. The result can only be as accurate as the microphone. A calibrated measurement mic has a known, flat response, so the processor corrects the car rather than the microphone; a phone's built-in microphone isn't individually calibrated like this one.
Alpine Australia describes moving the microphone around the cabin to capture the measurements, and Crutchfield describes the kit as plugging into the OPTIM8 to enable PC-based tuning. The long cable is the practical part: you can sit in the driver's seat, or reach the passenger side, without moving the processor or your laptop.
Which processors it works with, as Alpine publishes it
Alpine USA lists two compatible products, the OPTIM8 (PXE-C80-88) and OPTIM6 (PXE-C60-60), and Alpine Australia recommends it for the same two. Neither page names any other product. Alpine doesn't list the KTX-CSP1 for the PXE-R80-8, PXE-R100-8 or the other PXE processors we sell, and their product pages don't list automatic tuning, so don't buy the kit expecting it to add auto-EQ to them.
Alpine's OPTIM8 launch release, reprinted by 12voltnews in February 2023, shows where it fits. The app's guided steps show where to place the external microphone, which the release names as the KTX-CSP1 (for PC, sold separately), or the iPhone's built-in mic, and the release promotes a five-minute vehicle self-tune. It lists the OPTIM8 as compatible with the KTX-CSP1. The release covers the OPTIM8 only and mentions an iPhone app but no Android app, so for the OPTIM6, or an Android phone, ask us before you buy.
Do you need it?
If you own an OPTIM8 and want to tune from a laptop, Alpine's release names the KTX-CSP1 as the external microphone for PC use, and Alpine USA says it plugs directly into the processor. The release describes the iPhone app using the iPhone's built-in microphone, so phone-only tuning may not need the kit. It doesn't call the kit mandatory, and one owner below used a different calibrated microphone instead.
If you own any other Alpine processor, Alpine doesn't list the kit for it. A good installer will tune those by ear and with their own measurement tools; our guide to setting up a DSP in your car explains the process.
What owners and reviewers say about the Alpine KTX-CSP1
When we checked in October 2026, we found no owner reviews of the KTX-CSP1 itself; Crutchfield's listing, for example, shows none. Alpine's description of an ultra-precision microphone is promotional. What we did find are two owner reports on the OPTIM8 processor, which are related but not reviews of the microphone.
A US owner on the Maverick Truck Club forum (March 2024) called the measured response outstanding, with no significant dips or peaks, but found the initial correction curve far too bright and adjusted the target by hand. He praised hearing each PC-software change in real time and liked the 31-band EQ, though he couldn't find a way to apply one EQ change to several drivers at once. Notably, he skipped the KTX-CSP1 and used a different calibrated Dayton microphone on a TRRS cable, which he said cost about half as much. Alpine lists only its own kit, so that route is at your own risk.
An Indian owner on Team-BHP (November 2024) had a poor experience with an OPTIM8 in a Hyundai Creta N-Line: he described buggy firmware, limited manual control and an auto-EQ approach that didn't meet his sound-quality goals, and said Alpine India hadn't responded. Replies suggested involving a professional installer. Neither report says anything about the KTX-CSP1's own quality.
KTX-CSP1 vs other ways to measure
For OPTIM8 owners the release describes two routes. The free one is the iPhone's own microphone in the iPhone app. Next is the KTX-CSP1, which the release names as the external microphone for PC use. Installers also use stand-alone analysers such as JL Audio's MAX measurement system, a five-microphone dual-FFT analyser with an MRP of ₹4,99,990 that runs with JL's own TüN software. It is a separate tool, not an Alpine accessory, and far beyond what a single car owner needs.
Who should buy it, and who shouldn't
Buy the KTX-CSP1 if you own an OPTIM8 or OPTIM6 and plan to tune with Alpine's PC software.
Skip it if your processor isn't an OPTIM model, if you're happy with the iPhone app and your phone's microphone, or if a professional installer will tune the system with their own equipment.
Using it in an Indian car
Measurements are only useful if the car is quiet. Park away from traffic, close the doors and windows, and switch off the AC blower while the test signals play, even if that means measuring early in the morning in summer. Hold the microphone at ear height at each position the app asks for, and move it slowly and steadily. Run the cable so it can't snag on seat rails or get trapped in a door. If you'd rather not do it yourself, VA3 Car Studio offers professional installation in Ghaziabad.
Price and where to buy
The Alpine KTX-CSP1 has an India MRP of ₹10,999. VA3 Car Studio often sells below MRP, so check the current offer on the KTX-CSP1 product page, and tell us which processor you own so we can confirm it is the right accessory.
The bottom line
The KTX-CSP1 is a simple, well-specified tool with a narrow job: giving Alpine's OPTIM8 and OPTIM6 a calibrated ear. For OPTIM8 owners who tune on a PC, Alpine's release names it as the external microphone. For owners of other Alpine processors, Alpine doesn't list it, so check with us before buying.
Alpine KTX-CSP1 FAQ
Which processors does the Alpine KTX-CSP1 work with?
Alpine lists two: the OPTIM8 (PXE-C80-88) and the OPTIM6 (PXE-C60-60). Alpine doesn't list it for its other PXE processors, so check with us before buying it for anything else.
Do I need the KTX-CSP1 to tune an OPTIM8?
Alpine's launch release names it as the external microphone for PC tuning and describes the iPhone app using the iPhone's built-in microphone. It doesn't call the kit mandatory, and one owner plugged a different calibrated microphone into the processor instead.
Will the KTX-CSP1 add auto-tuning to the PXE-R80-8 or PXE-R100-8?
No such use is published. Alpine lists the kit only for the OPTIM8 and OPTIM6, and the R80-8 and R100-8 product pages don't list automatic tuning.
Buy Alpine DSP Processors in India
Check the Alpine KTX-CSP1 Measurement Microphone Kit for OPTIM8 / OPTIM6 price in India, browse more Alpine DSP processors or compare all car DSP processors in India. Want it fitted properly? Book DSP installation and tuning at our Ghaziabad studio.
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