Alpha & Delta KS1 Review

Alpha & Delta KS1 review featured

Alpha & Delta website:

Alpha & Delta is a Singapore-based company that manufactures in-ear monitors. In today’s review, I’m taking a look at their latest iem, the Alpha & Delta KS1. Equipped with a custom-tuned 8mm graphene dual magnetic driver, the KS1 is coined as being “the baby brother to the A&D KS3” which I reviewed here. How will this budget edition fare against its big brother and also against other budget earphones? Let’s find out.

Disclaimer: This sample was provided for the purpose of an honest review. All observations and opinions here are my own based on my experience with the product.

Alpha & Delta KS1 Review

  • Build quality
  • Great comfort and noise isolation
  • Detachable cable
  • Clear, coherent sound
  • Value for money

  • Treble is a little peaky

Package and Accessories


Similar to the KS3 packaging, the KS1 comes in a small box with a transparent plastic cover. The earphones can be seen seated in a plastic insert and there’s a classy looking black accessory box with embossed gold print on the front.

Here’s what you get in the box:

  • Alpha & Delta KS1 earphones
  • Detachable 2-pin 3.5mm cable
  • Fabric carrying pouch
  • 3 pairs of black wide-bore silicone eartips
  • 3 pairs of white narrow-bore silicone eartips
  • 1 pair of black foam eartips
KS1 box contents

Build Quality and Design

Alpha & Delta KS1 with Shanling M5s

The A&D KS1 iems are made of a smooth medical-grade resin and have smoky-grey transparent shells. There are 4 colours available for the faceplates, including black, red, silver and blue. A silver-coloured A&D logo sits flush in the middle of the faceplates.

For a budget iem, these look and feel really nice, similar to the KS3 and other earphones like the TRN IM2. The nozzles are metal for extra durability and have a solid lip to help keep eartips securely in place. In addition, there’s a metal grill covering the mouth of the nozzle to keep that nasty ear wax and other things out.

Internally, the KS1 has a custom-tuned 8mm graphene dual magnetic driver which can be clearly observed through the transparent shells. Overall, the build quality feels durable and really good for something in this price range.

Comfort and Noise Isolation

According to A&D, the KS1 housing design is based on 3000 ear impressions. I’m willing to believe it because these are some of the most comfortable in-ears I’ve used. They just disappear in your ears and feel very natural. In addition, they have a low profile so they don’t stick out from your ears which makes them great for lying down with.

Noise isolation is very good so these are great if you don’t want to hear your spouse or parents nagging. It also makes them very practical for commuting as they block out a good deal of external noise.

Alpha & Delta KS1 cable and DAP

Included with the KS1 is a basic generic cable. It’s a 4-strand twisted cable with a glossy black insulation and you may have seen the same type included with other budget earphones as it’s a fairly common one.

It actually handles quite well and has minimal microphonics so I think most people would be satisfied with it. Of course, it can be swapped out if desired for another one as it is detachable and has a standard 2-pin connector.


Gear used for testing includes the Shanling M5s as a portable source and on the desktop, I used my Singxer SDA-2, in conjunction with the Phatlab Chimera portable amplifier. A bit overkill perhaps but hey, we’re all #stuckathome right now so why not spoil ourselves a little right?

The Alpha & Delta KS1 has a classic V-shape signature that most people will be familiar with. It has a warm presentation with a lightly accented bass and treble with a mildly recessed midrange.


The bass is tastefully done and of surprising quality for a budget iem. Mid-bass is punchy and fast but also delivers with sufficient impact and slam. Sub-bass reaches low and has really nice extension with a tight, controlled rumble.

Slowly Rolling Camera’s “Eight Days” is a laidback, cruisy track based around an acoustic guitar, piano and saxophone. But the kick drum (starting at 1:34) hits pretty hard and the KS1 handles it really nicely, delivering it with a powerful thump but never obstructing the midrange instruments. It shows an ability to create layers in the bass that a lot of budget alternatives simply can’t match.


Although the KS1 has a V-shaped signature, the midrange is relatively forward in the overall presentation. Gazpacho’s “What Did I Do” is a haunting song with a focus on the vocals. Listening with the KS1, the vocals are upfront and prominent, quite intimate but presented in a large soundstage with the vocals centrally positioned and the instruments spread further out towards the edges of the stage.

Midrange resolution is above average for a single dynamic driver earphone, especially in the budget range. Listening to Katatonia’s “The Promise Of Deceit” the KS1 holds things together admirably during the busy segments. The male vocals are a bit thin sounding but on the plus side, have good diction.


The treble is what I consider the weakest element of the KS1. It can be a bit splashy and thin, sometimes making cymbals sound artificial and shrill. Long Distance Calling’s “On The Verge” is a song that highlights this characteristic and the cymbals throughout the second half of the song sound quite splashy.

Of course, there are upsides to these treble peaks, namely additional clarity and definition but on certain tracks, it’s a little too much for comfort. However, people that enjoy a bit of shimmer up top will probably find it quite enjoyable.


The soundstage dimensions are quite good and give the impression of somewhere between a large room and a small hall. With fairly precise imaging, the KS1 draws a clear picture of instrument positions and is pretty good with layering too, particularly for a budget iem. Instrument separation is above average and the KS1 rarely shows any signs of congestion.

Alpha & Delta KS1 earphones


BLON BL-03 ($29)

The BLON BL-03 (review here), is another single dynamic driver earphone and one that became the budget favourite of 2019. It’s not without shortcomings though – in particular, the stock cable and eartips that most people end up replacing.

It has a more natural tonality compared to the KS1 but not the same level of detail. The BLON is warmer and has more fullness to its presentation. Both iems have similar sub-bass but that’s about where the resemblances end. BL-03’s mid-bass is more prominent, thicker and full-bodied. It’s not as fast or tight as the KS1 bass, nor is it as textured.

Moving on to the midrange, the BL-03 is again fuller and warmer. Instruments and vocals are more upfront but the KS1 has the edge here in terms of instrument separation. The BLON is more musical here compared to the KS1 but also more prone to congestion.

When it comes to treble, the BL-03 is more subdued and less peaky. It has less emphasis on the lower treble, instead of focusing more on the 9-11kHz range. This helps it maintain clarity and timbre while at the same time avoiding harshness.

KZ Z10 Pro ($20-30)

The KZ ZS10 Pro (review here) is a 5-driver hybrid iem (1DD+4BA). It’s much more upfront in every aspect compared to the KS1. ZS10 Pro is bold, energetic and takes no prisoners. With its multi-driver configuration, the ZS10 Pro is able to surpass the KS1 in separation and resolution.

It has significantly more sub and mid-bass but thankfully it’s still pretty tight. The low end is thicker and warmer and that carries throughout the midrange. The midrange is brought forward and is thicker than the KS1 but the transients are still very fast (BA drivers at work).

When you look at the graph above, it looks as though the ZS10 Pro should be hotter and harsher in the treble but it isn’t. It’s less splashy and doesn’t exhibit the same harshness as the KS1. It can be fatiguing in its own way – big bass, in your face sound, lots of detail: the ZS10 Pro is quite demanding on the listener from top to bottom. On the other hand, the KS1 is more coherent but it has a sharper treble.

KS1 with carry pouch and DAP


The Alpha & Delta KS1 is a competent iem in the budget category. Its standout feature is the tight bass which it handles better than most in this price range. It has a V-shaped signature with a clear, articulate midrange and lively treble. Those who like a bit of shimmer and detail in the top end will likely appreciate the extra energy in the highs.

Another prominent feature of the KS1 is the excellent build quality and comfort. These are a super comfortable earphone and their diminutive size is great for those with smaller ears. Alpha & Delta consistently provide great value with their earphones and they’ve done it again with the KS1.

  • Driver Unit: 8mm graphene micro driver
  • Impedance: 16 ohm
  • Rated power: 1mW
  • Frequency response: 10 Hz- 20 Khz
  • Speaker sensitity : 105 +/- db/mW
  • Cord Length: 1.2m silver plated copper cable
  • Plug: 3.5mm

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