The 64 Audio A4s is your gateway to auditory bliss. Four groundbreaking drivers and a slew of cutting-edge 64 Audio technologies like Apex, tia, and LID combine to guarantee extraordinary fidelity for a sound experience you'll never forget.
Everything you need is included with the 64Audio A4s IEMs!
The A4s custom IEM features 64Audio's patented 3Dfit technology for guaranteed fit and comfort.
3Dfit is a revolutionary process that ensures your ear molds are reproduced with astonishing accuracy while integrating acoustical tuning features in the IEM shell for sound precision and comfort you just won't get with any other custom IEM.
The A4s is only the second custom in-ear monitor in 64Audio's stable to feature a dynamic driver hybrid setup. Paired with 64Audio's patented tia system, the A4s delivers a complete high-quality sound experience that's perfect for both professional audio work or casual listening.
It is well-known that a dynamic driver delivers some of the most natural and visceral sounding low-end of any driver type. With a special dynamic driver driving the A4s' bass, you'll experience deep rumbles like never before and feel a powerful punch in your favorite music.
On the other hand, 64Audio's tia open drivers and open bore design deliver outstanding clarity and immaculate details for a truly immersive sound experience like no other.
IEMs can cause discomfort over time, caused by unavoidable pressure buildup typical of the air-tight seal created by in-ear monitors to ensure proper sound delivery.
You'll never have to worry about discomfort with the A4s. The glove-like fit created by the ultra-accurate 3Dfit shells is enhanced by 64Audio's revolutionary air-pressure release system called Apex.
Apex vents extra air from the sealed ear canal to ensure you don't suffer from discomfort caused by pressure buildup over time. The result is unbeatable comfort for distraction-free extended listening sessions and a more natural and immersive soundstage.
Your audio source affects the sound quality of your in-ear monitors due to varying electrical resistances in multi-driver in-ear monitors.
With Linear Impedance Design, you'll never have to worry about inconsistent sound quality on the A4s.
LID ensures the dynamic driver and Balanced Armatures in the A4s remain faithful to the original sound signature so you can experience only the purest sound - no matter your source. Whether you're using your smartphone, bodypack, DAC/Amp, or DAP, rest assured you'll hear every note with precision and accuracy on the 64Audio A4s.
A3t:
Drivers: 3 Drivers
Impedance: 11Ω @ 1kHz
Frequency Response: 20Hz – 20kHz
Sensitivity: 109 dB/mW @ 1kHz (105mV)
A4s:
Drivers: 4 Drivers
Impedance: 11Ω Nominal
Frequency Response: 10Hz – 20kHz
Sensitivity: 107 dB/mW @ 1kHz @ 1mW (94mV)
Our Analysis:
The A4s is a premium custom IEM from 64Audio. Priced at $1,099, the A4s delivers a fantastic low-end response for listening to bass-heavy music.
| Specification | Description |
| Driver Type/Count: | 1 dynamic low, 1 BA low-mid, 1 BA high-mid, 1 tia high |
| Frequency Response: | 10Hz – 20kHz |
| Sensitivity: | 107 dB/mW (94mV) @ 1kHz |
| Impedance: | 11Ω @ 1kHz |
| Crossover: | Integrated 4-way passive crossover |
| Isolation: | 20dB w/ m20 module, -15dB w/ m15 module. Ships with M20 Module standard |
Shipping is FREE on all orders to customers within the USA.
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Here's how shipping works around here:
We get it. Audio gear can be subjective. That's why we offer our industry-leading 365 day return policy. Here's a quick rundown;
We get it. You've got a lot of choice when it comes to online retailers. Here's why we think you should shop with us at HiFiSoundGear.
Ordering Process:
At HiFiSoundGear, we understand that the journey to perfect audio is unique for every individual. We also understand that the custom IEM ordering process can be confusing at times. That's why our custom IEM ordering process is designed to be as seamless and supportive as possible.
Here's how we do it:
1) Choose your custom IEM model, add to cart, and proceed through checkout. This authorizes payment for the base IEM, and gets the ordering process started.
2) We'll reach out with an order confirmation and send you a form with instructions on choosing your custom options. You can fill out the form yourself, or contact us by phone or email. We're happy to fill in the options for you - just let us know what you're looking for!
3) If you've chosen any options that have an extra cost associated with them, we'll handle it at this point of the process with an invoice. (Custom artwork, wood faceplates, etc.)
4) We'll find a few audiologists in your area and work on helping you get an appointment set for your impressions! All you need to do is show up. We'll provide you with a special guide and instructions for your audiologist.
5) Send us pictures of your impressions so that we can verify whether they can be used for production. This prevents the headache of shipping your impressions only to find that they are not detailed enough.
6) We'll send you a shipping label and a confirmation sheet for your impressions, marked and addressed to the right place.
7) We'll confirm that your impressions have been received, and that the production of your custom IEMs has begun! Expect to wait 4-6 weeks for production and final shipment. (Bellos Audio X-Series are 1-week production time)
As always, we're available to help at any point of the process. Just reach out by phone at (888) 926-8024 or by e-mail at info@hifisoundgear.com.
Returns
Refunds, returns, and exchanges are NOT available for custom IEMs after your order has been submitted and production has started, due to the highly custom nature of the product.
Unexpected as in very pleasantly surprised at the sound quality coming out of these :)
I took my Mega5-EST and hooked em up wirelessly and don't miss the wire sound AT ALL!! IMO the wireless sound was 98% of the wired sound without the PIA of the wire. Unless you have some amazing source gear, which thanks to Adam at hifisoundgear I do, you would be hard pressed to hear a massive difference. Especially with a phone as your source.
I did A/B noble Fokus Prestige vs Go pod w Mega 5 and gotta say l, there is more balanced sound with the Go pod chain then the Prestige on its own. To be fair the Mega 5 punches WAY above its price... so the 2 are a match made in heaven.
I find the connection very stable as well. I've used my iPhone AAC/SBC as well as with FiiO BT11 to get other than Apple codecs and was pleasantly surprised as well.
The ear hooks are very comfortable. Actually prefer them to the wire hanging over my ear with a tie behind my neck. For some reason that's hard to get used to and pulls as I wear loose shirts. The hooks stay in as I like to move around a bit. Also the weight is better distributed than other wireless IEMs as the components are in the hooks. The prestige, unless I have foam tips, which I'm not a fan of, will pop out of my ears when I move around. These stay stable and I do not have to re-seat the IEMs to get that great bass nearly as often with other wireless IEMs.
Battery level has been all day 10 hrs so far with intermittent breaks and still have 28% left.
The case also is deep enough to fit the Mega w hooks as it charges which is very convenient. Some IEMs may be too big but they fit with a tad bit of room to spare.
Of course having the flexibility to swap out your favorite IEMs as needed is awesome!!
5 stars for the Go pod and more importantly 5 stars to Adam and his team for such amazingly awesome customer service!! You guys ROCK!! Thanks :)
The iFi Audio iDSD Diablo 2 is an absolute masterpiece in the world of portable amps. It delivers an audio experience that redefines what’s possible in a compact, travel-friendly device.
To all the "haters" out there who mention that the 5180mw output is an overstatement and the "balanced" is not a true balanced output... I say whatever... it drives anything I throw at it with aplomb! FostexTH900mk2, ZMF Caldera Open and Closed, ANY IEM my friends and I have tried ...too many to list. If you need more power than this portable titan.... well you may have hearing loss. And it drives all I mentioned without using "beast mode" (they refer to it as Nitro (1 of 3 settings)). If anything, it could use a lower gain option / IEM match for some sensitive IEMs.
The implementation of BT 5.4 (supports all codecs) is a welcomed addition for quality, but in general, the distance it can be from the source is very small for consistency. That is not a Diablo issue, but a BT5.4 issue IMO.
As for the sound quality...simply unparalleled. I have compared this to desktop headphone amps in the same price range and I would put it toe to toe with them. It even ran close to my buddy's Burson Soloist 3x!!! and the Diablo 2 is portable :)
I run it using A&K SP3000T and it oozes warmth and richness in the lows and highs WITHOUT covering/smoothing anything up in the mids, which is my jam.
It is on the heavier side and will still fit in a pocket... barely. built like a brick. At the limit of what I would like to carry but totally worth it! I get about 6 hours of the 8 rated battery with constant listening, no Bluetooth on, hard wired, IEMs / Caldera tested on the battery life.
In conclusion, the iFi Audio iDSD Diablo 2 is nothing short of extraordinary. It’s the ultimate portable amp for those who refuse to compromise on sound quality, power, or versatility. If you’re serious about your audio and want the best experience on the go, the Diablo 2 is the perfect choice.
Shout out to Adam, a massive THANK YOU!!! for your absolutely OVER THE TOP customer service and shopping experience :) :) Seriously, your dedication and attention to detail have been nothing short of exceptional.
With all the online ordering over the years, HifiSoundGear provides the best service I have encountered. It was as though they were good friends. They responded so nicely to all my questions about the product and shipment. As it works out, while I liked the IEM's, I concluded they were not sufficiently different from the ones i had been using. Again, for the process of returning and getting a refund, they could not have been nicer. Buying from them was a first rate experience.
Recently had a great experience with Adam and Laura. I requested a price match for the FiR KR5 and it was such a painless process. Adam and Laura’s communication is top notch! Adam even sent me a personal thank you video. In my experience, this level of service is hard to come by these days. I highly recommend going through HifiSoundgear for your audio needs….I know I will be going forward! Thanks Adam and Laura!
The quality of service, level of help provided, and overall customer satisfaction is beyond anything I have experienced. I cannot say enough good things about the people who belong to this company!
As for the U4S, these are my first foray into 64 Audio but I am SO thankful that I got to experience them! My goodness the soundstage, bass response from the m15 module, and overall quality is just great!
Please, buy from these wonderful people! And if you can swing it, get a set of U4S! You will not regret it!
Only complaint is the cable. For the price, I expected better, but it works well and is just fine.
Thank you HiFi Sound Gear! I look forward to purchasing more from you in the future!
These are the closest TWS gets to pure IEM listening. You get the wide soundstage. They scale quickly. They have that satisfying bass slam often missing in TWS. The layering is just right and resolution is mesmerizing. Oh yes, you get the convenience of taking them on the go and they are truly comfortable. Noble has achieved a superior status in my eyes with the FoKus Prestige. I look forward to listening to them on my walks when I don’t have to take my DAP. Adam is one of the greats in this business. His commitment to customer service is exceptional. You aren’t a customer, but a client. He helped me after losing my first pair and just went above and beyond to ensure that I was shipped a new pair in less than two days. I am completely satisfied and impressed. You will be too. Thank you and looking forward to my future purchases from your establishment.
HifiSoundGear offers exceptional quality products and unparalleled customer service. Their wide selection of high-end audio gear, including in-ear monitors and amplifiers, are praised for delivering outstanding sound clarity, detail, and an immersive listening...
