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ZMF Caldera Headphone Review

Rate this headphone:

  • 1. Poor (headless panther)

    Votes: 47 25.7%
  • 2. Not terrible (postman panther)

    Votes: 85 46.4%
  • 3. Fine (happy panther)

    Votes: 31 16.9%
  • 4. Great (golfing panther)

    Votes: 20 10.9%

  • Total voters
    183
I would love to try an empyrical experiment. Gathering a group of people advocating for harman target in this thread and let them do "a blind test" of Caldera stock tuning and with the EQ amir came up with "that makes Caldera sound excellent" then they can state which tuning they liked more. I imagine the results to be very fun.
 
Indeed, I hope it wont be long until chinese manufacturers start implementing 10band PEQ on DACs like RME, but priced for the masses. I mean, at some point they have to stop chasing an extra DB of SINAD per year dont they? XD

/dreams
Funny enough, 7-10+ band PEQ is already implemented on many (maybe most) bluetooth speakers and headphones. It wouldn't add more than $20 at retail to implement it on DACs. It's just that it's used for tuning, graphic EQ, or not used rather than exposed as PEQ through an app. The module makers don't build or maintain a user-facing app, and most audio manufacturers don't particularly want to maintain an app. Even if they so, even up through brands like KEF, manufacturers don't believe users will be able to use PEQ effectively.

In my experience doing customer support for audio, they are correct... (the concept of "frequency" is already pretty hazy for mainstream folks, let alone Q.) but I still wish they'd just offer an "advanced mode" buried in menus or something.
 
I would love to try an empyrical experiment. Gathering a group of people advocating for harman target in this thread and let them do "a blind test" of Caldera stock tuning and with the EQ amir came up with "that makes Caldera sound excellent" then they can state which tuning they liked more. I imagine the results to be very fun.
It is a good idea but why should you volunteer for that? Shouldn't that have been the starting point for design of this headphone by the company?

That aside, that is precisely what Harman has done in its research into target frequency response. They used a surrogate headphone and equalized it to many other curves of other headphones. The results of that research (and then some) is what I use.

BTW, can you post the equalization you used? I want to make sure it is correct.
 
It is a good idea but why should you volunteer for that? Shouldn't that have been the starting point for design of this headphone by the company?

That aside, that is precisely what Harman has done in its research into target frequency response. They used a surrogate headphone and equalized it to many other curves of other headphones. The results of that research (and then some) is what I use.

BTW, can you post the equalization you used? I want to make sure it is correct.

For knowledge, since thats what all of this is about in the end. Empyrical experiments are always more fun than theoretical tribalist discussions. Not sure I understand how you imagine this to be part of a headphone development but I think it would be an interesting event to find a consensus in this discussion.

I am on a working trip next 2 weeks, just with my dap and a verite closed :) Will try to remember to post, otherwise feel free to ping me. I am certain to have copied your EQ with care and I spent a lot of time with it before posting any conclusions.
 
For knowledge, since thats what all of this is about in the end. Empyrical experiments are always more fun than theoretical tribalist discussions. Not sure I understand how you imagine this to be part of a headphone development but I think it would be an interesting event to find a consensus in this discussion.
??? If a company wants to invent their own "house sound," do you think it merits performing the very experiment you mentioned? You think they should go and build it with a prayer that it sounds good to people? Or that the designer's view is gospel and must be right???
 
I am on a working trip next 2 weeks, just with my dap and a verite closed :) Will try to remember to post, otherwise feel free to ping me. I am certain to have copied your EQ with care and I spent a lot of time with it before posting any conclusions.
Would have been nice to not have to wait that long. Anyway, when you get back, get an audiophile friend and run a blind test on him/her with/without EQ. Repeat at least 10 times and use a few varied audio samples. Keep a log and then see where the chips fall.
 
@amirm - If you are going to be continuing to ruin this forum responsibly, you really need to get the rig that most/many us manufacturers are using which is the 5128 from B/K. It will accurately give you results above 8K and more properly show the rest.
I am assuming you are not a regular reader of this forum because if you were, you would have known that I first evaluated BK 5128 before purchasing the GRAS 45CA. There are no research backed targets for 5128 which to me was a showstopper. I would be spending a lifetime defending some target I would make up for it. As for accuracy above 8 kHz, small variations in headphone mounting will result in large variations there regardless of which fixture you use. Theory is not the same as practice here.

FYI, I did see your 5128 measurements for Caldera. If your website was not written in a way that wouldn't allow linking to images, I was going to include them in my review. I encourage you to post those measurements and explain to us why it tells you what you want to know. BTW, I did appreciate your posting those measurements -- something almost none of your competitors do.

As to ruining this forum with the way I test headphones, I suggest you do some research. I will get you started on popularity of our site vs Head-fi.org which has been around far longer than we have:

1701462950114.png


Knock on wood, seems like we are doing OK. :)
 
Would there be any chance that you could send these models to Amir, in each configuratiom for review, for the benefit of the consumer and the overall audio community? All these different options and configurations would be impossible to compare at home, or even at a headphone show, where the presenters are sometimes far less technically sound as you obviously are.


I want to purchase a pair of your headphones, but the reviews are all over the place to risk $1,500 - $3,500. Whoever does your wood work is amazing. You have by far the best looking headphones on the market, in my opinion.


Amir can be a bit steadfast, but why not work with this site for the fans by sending him the gear for review as YOU have designed them. Fly out, and do a video together. Yes I know your are busy, and why should you sacrifice , or bend to one particular market base. I get that, but it would be awesome to see any of these bigger names to reach across the aisle. Amir is not leaving the Pacific Northwest, but I think it would be awesome to see, instead of all this bickering.


Most of the other site reviewers have all these different standards and everyone has their own listening curves, without the large data set like the harman study.

If all the manufacturers are now using the 5128, wouldn't it help the hobby, and the science if a new study was completed using the 5128 was compiled before everyone decides the science of the GRAS system is no longer useful to the current hobbyist base?


@amirm - If you are going to be continuing to ruin this forum responsibly, you really need to get the rig that most/many us manufacturers are using which is the 5128 from B/K. It will accurately give you results above 8K and more properly show the rest. I know the 711 coupler is great since it will reflect the Harman research, but the industry is moving past that as the 711 coupler is dated at this point. Maybe you can develop some findings with your own research more based on what your personal HRTF is as we all have large variances in certain areas.

Further - and as any ZMF owner will tell you, there's 6 sets of different pads for the Caldera, and a titanium mesh for the front that helps tune the headphone to your preferences/HRTF and without testing all of that the way an actual owner is and finding what works best for your own personal HRTF BEFORE doing EQ you are also doing a dis-service to anyone who reads this by stating "facts" without utilizing the headphone in it's designed sonic modular fashion. For example there's three different depths of Caldera pads, all which adjust the distance of the driver to the ear to account for different anatomies, as well as a fully perforated pad that more follows harman.

Please be more responsible and use the headphone the way an owner would, so you can provide accurate information since you have so many followers.

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@solderdude and everyone else who has commented on the tuning of ZMF's. I work with, and know most manufacturers, and have talked at length with all of them about the Harman curve and ofcourse read all the research and as you know designed and tuned many headphones. And for anyone who does this laborious practice of spending years at a time tuning a single headphone, you try many things. I use and own flat panel, DIY, 711 coupled Larson Davis AEC206, and two 5128's from B/K. I measure every headphone and driver I design in various stages and always tune much closer to harman just to try what each headphone will sound like, as I do want to test and utilize the great research that Sean Olive has done because I am not a denier of it and find it useful.

But what Sean Olive will tell you, as any other responsible headphone MFR that actually makes headphones, that the harman curve was meant as a starting point not as a defined endpoint that all headphones need to meet to be enjoyable.

Each system, driver/cups etc has many innate qualities of airflow that are measured in other ways, some that are worth exploring via measurements and some that are experienced more subjectively that are the culmination of many measurements like THD, FR, impulse, CSD, bursts etc. Further, open vs closed full sized headphones vary quite differently in how we each experience them when tuned the same. I know this because when I'm working on the closed version (and vice-versa) of each of our open headphones I tune them to match, and also tune them to harman and then EQ them to harman, and every single time the closed version or open version tuned like the other sound way different. There's just so much more that goes into how we experience sound aside from FR.

I'm pretty sure there's many of you on this forum who enjoy a headphone that isn't tuned exactly to @amirm 's cult of Harman tuning, but are afraid to speak up because of the insane groupthink that happens here. I'm here to tell you that it's OK, because all of us on the side of things that are actually making headphones, know that there are many variations, including liking the Harman curve that can be enjoyable for many different reasons. I implore you to like what you like and stand up for yourself, because there's a reason you like what you like, and you're not alone!!!!

Many people seem to think our headphones are just me sitting in a basement tuning the headphones and making sure they look some special woody way, this is just not true. I do tons of acoustic research and testing on each headphone and they are tuned in very specific ways based on the driver and platform (open/closed/semi-open) that they exist within. I follow advice, thoughts and measurements from many sources before they are released and you'll find that none-of our headphones have .1 // .2 // .3 versions after they are released. If you don't like them because they are not tuned to harman that is totally awesome and cool! But I would implore more of you to actually listen to the Caldera before posting here, and do more work to find what your actual HRTF is because that's what my headphone designing is all about, making a platform that is semi-modular within the pads and damping mesh where a gamut of owners can end up with something they really like.

BONUS COMMENT: If you want a ZMF that is tuned to closer harman, the Atrium Closed with suede pads is quite close. I don't particularly love the way it sounds due to my HRTF, I like the lambskin version that has quite a bit more mid-bass and is below harman in the 4-6 khz area.

BONUS II: If you want a Caldera that conforms closest to harman, use the ultra perf pads, gently EQ to the curve in the area (less has to be done) and then EQ the bass up as the ultra perf will cause a roll-off below 70 HZ. I know about 2 out of hundreds of owners who prefer this, but if that's what you're into, it's the easiest way to get there.
 
Further - and as any ZMF owner will tell you, there's 6 sets of different pads for the Caldera, and a titanium mesh for the front that helps tune the headphone to your preferences/HRTF and without testing all of that the way an actual owner is and finding what works best for your own personal HRTF BEFORE doing EQ you are also doing a dis-service to anyone who reads this by stating "facts" without utilizing the headphone in it's designed sonic modular fashion. For example there's three different depths of Caldera pads, all which adjust the distance of the driver to the ear to account for different anatomies, as well as a fully perforated pad that more follows harman.
For starters, you should clearly post measurements of all of these pads. Second, are you saying that with a different pad the bass response would jump up nearly 7 dB to comply with Harman's target??? Love to see that measurement.

If you want to send me the pad that does bring the headphone to compliance, I am happy to test it. I recall you joining the forum a while ago and offering to send me headphones for testing but nothing happened.
 
I am assuming you are not a regular reader of this forum because if you were, you would have known that I first evaluated BK 5128 before purchasing the GRAS 45CA. There are no research backed targets for 5128 which to me was a showstopper. I would be spending a lifetime defending some target I would make up for it. As for accuracy above 8 kHz, small variations in headphone mounting will result in large variations there regardless of which fixture you use. Theory is not the same as practice here.

FYI, I did see your 5128 measurements for Caldera. If your website was not written in a way that wouldn't allow linking to images, I was going to include them in my review. I encourage you to post those measurements and explain to us why it tells you what you want to know. BTW, I did appreciate your posting those measurements -- something almost none of your competitors do.

As to ruining this forum with the way I test headphones, I suggest you do some research. I will get you started on popularity of our site vs Head-fi.org which has been around far longer than we have:

View attachment 330986

Knock on wood, seems like we are doing OK. :)
(I agree, but I think he did a typo and meant to say "run" rather than "ruin".)
 
Please be more responsible and use the headphone the way an owner would, so you can provide accurate information since you have so many followers.
An owner sent me this headphone and I tested it exactly that way. Per above, you could have sent me a headphone and told me which one to use but since you did not, I test what is sent to me.
 
If all the manufacturers are now using the 5128, wouldn't it help the hobby, and the science if a new study was completed using the 5128 was compiled before everyone decides the science of the GRAS system is no longer useful to the current hobbyist base?
I'm sorry to keep banging this drum, but I really feel like it's important to emphasize this: essentially no new study can make the older 60318-4/7/GRAS gear stop being useful. We have decades of research correlating perception and measured results on such systems. That, again, doesn't mean that we can't improve, but one would essentially have to overturn the majority of all work on headphones (and much of the work on sound perception in general) that occurred from 1980-present in order to conclude that the GRAS measurements are no longer useful.

I know this is a pedantic point, but I see this brought up quite a lot, and I think it's really quite important that we keep in mind that we have years of significant correlations of human perception and measurements from these fixtures. Unless all of that work is somehow overturned, we can only innovate by improving new methods, not by demonstrating that the older ear sims are somehow fundamentally unsuitable.
 
But what Sean Olive will tell you, as any other responsible headphone MFR that actually makes headphones, that the harman curve was meant as a starting point not as a defined endpoint that all headphones need to meet to be enjoyable.
I don't think he said it is "starting point" but yes, by definition, a smoothed target combined with "circle of confusion" can't be fully prescriptive. This is why I listen to every headphone without EQ. And then apply EQ based on target to see if it makes it sound right. If it doesn't, I will modify/adjust the response to get it there and note that in the review. I noted that here.

As I also noted in the review, I don't mind you having a different target. Just spend half a day and perform blind tests to see if they are preferable to Harman target. Without it, you are expressing opinion, not facts.
 
I believe it was a typo "running this forum".

No I just think a blind A/B test between the stock tuning proposed EQ that you came up with on an evening or two and adamantly claimed to make a headphone "excellent" that a knowledgeable designer finetuned and designed for many years, would open up many eyes on ASR and your reviews in general.
OR prove your point.

And yeah, I dont quite follow how you imagine such experiment to happen during the development, but considering how open ZMF are about their work, I doubt the guys woud say no, if you Amir dropped by in the workshop to discuss some ideas and maybe even implement and compare some tunings. I believe Caldera Closed is currently in development. But this would imply a certain degree of humility, mutural respect and curiousity.

I dont think ZMF tries to invent a house sound, the headphones are simply tuned to a preference of an experienced designer that still uses harman target for reference but deviates from it in search of something he wants to achieve with a particular design. I dont think that ZMF owners are dead set to see Zach as any kind of messiah.If you read head-fi you will see that plenty people who are buying ZMF stuff, own or owned many other totl headphones, people simply enjoying the tuning Zach comes up with, some stay with ZMF some move on, in my experience if there is a common dominator, its the crowd that enjoys the trip, discovering new and fun tunings.
For me personally each new release in the recent years brought sonically something new and very enjoyable to the table which is rare. And I listen to A LOT of stuff regullary visiting fairs and local meet-ups.
 
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I'm pretty sure there's many of you on this forum who enjoy a headphone that isn't tuned exactly to @amirm 's cult of Harman tuning, but are afraid to speak up because of the insane groupthink that happens here.
You are sure of many things that are not true and this is one of them. Some of the bloodiest battles here are around headphone measurements, preferences, fixtures, etc. I have spent days arguing with people in these threads.

At the end of the day, we are getting work done. I have tested nearly 100 headphones and importantly, some 300 speakers. I provide my frequency responses for all to use together with equalization to try. All of this has built up a level of confidence that entices members to continue to send me headphones to test including one of your customers.

As I said in the other post, there will never be anything approaching 100% with headphones. But we can still get work done and separate the bad from good. From a sample of good, members can choose what suits them best.

BTW, I am personally disappointed in the tone of your responses. Did you not notice that I gave your headphone the highest award possible with EQ? This, despite its high cost? I also complimented the looks, build, etc. I suggest taking a moment to appreciate that before posting remarks like this.
 
No I just think a blind A/B test between the stock tuning proposed EQ that you came up with on an evening or two and are adamantly claimed to make a headphone "excellent" that a knowledgeable designer finetuned and designed for many years, would open up many eyes on ASR and your reviews in general.
OR prove your point.
There are plenty of "knowledgeable designers" whose products get poor marks from me and membership at large. We are not here to worship heroes. They are not here doing anything for us. We use their products and the performance of the product is what matters.

In this case, I am not aware of any qualifications of the designer in coming up with a preferred target for headphones. I know of no training he has in that regard or education. Many designers are similarly situated. His demonstrated expertise is in building headphones (which I praised). Not getting the response right. For that, we need much more than his claims and yours.

The experiment is dead simple and can be run in half hour with a single listener. You have them wear the headphone, equalize levels (with and without EQ), and randomly select EQ or not. Repeat a dozen times. Try it with a few songs. Then do a simple statistical analysis to see if they are right in preferring one EQ more than the other with lower probability of chance than 5%. If you don't know how to do this math, post the results here and we will do it for you.
 
I'm pretty sure there's many of you on this forum who enjoy a headphone that isn't tuned exactly to @amirm 's cult of Harman tuning, but are afraid to speak up because of the insane groupthink that happens here. I'm here to tell you that it's OK, because all of us on the side of things that are actually making headphones, know that there are many variations, including liking the Harman curve that can be enjoyable for many different reasons. I implore you to like what you like and stand up for yourself, because there's a reason you like what you like, and you're not alone!!!!
Sigh* I've been showing off my PEQ settings for a long time and nobody freaks out... LoL. ChiLax!
z Screenshot 2023-04-08 230137.png
 
I dont think ZMF tries to invent a house sound, the headphones are simply tuned to a preference of an experienced designer that still uses harman target for reference but deviates from it in search of something he wants to achieve with a particular design.
He should do that for himself then. If he is going to do it for the rest of us, we are going to scrutinize it. To my ears, it lacks bass to the point that my bass heavy reference tracks are totally bland and unenjoyable. As it happens, research into headphone targets explains why I feel that way. There is nothing "Harman like" here. It is directly opposed actually. As are the dips in frequency response which we know from speaker research to be bad. I paid for all of my music and expect playback gear to produce all of it. Not decided arbitrary to take out some segments!
 
There are plenty of "knowledgeable designers" whose products get poor marks from me and membership at large. We are not here to worship heroes. They are not here doing anything for us. We use their products and the performance of the product is what matters.
From my plain life experience if someone spends over a decade with something and is successful with it, there will be a fair amount of knowledge.It rarely occurs that people poke in the dark for 10 years without any idea of what they are doing which your review implies and yet are successful with what they do. More and more people enjoy ZMF tuning and advice others to try a ZMF for a reason. People are here for sound in the first place, great craftsmanship and customer care is a cherry on top. Yes I do think Zach has a fair amount of experience with tuning a headphone design from ground up.

The experiment is dead simple and can be run in half hour with a single listener. You have them wear the headphone, equalize levels (with and without EQ), and randomly select EQ or not. Repeat a dozen times. Try it with a few songs. Then do a simple statistical analysis to see if they are right in preferring one EQ more than the other with lower probabily of chance than 5%. If you don't know how to do this math, post the results here and we will do it for you.
I think there will be a lot of bias and room for manipulation with this approach. I for my part can easily tell your tuning from stock tuning. And I think anyone with bit of experience will do. Blind A/B testing with a larger focus group without any prior knowledge of this discussion would be fun though. I would place a bet for more people enjoying stock tuning for the reasons I mentioned previously.
To my ears, it lacks bass to the point that my bass heavy reference tracks are totally bland and unenjoyable. As it happens, research into headphone targets explains why I feel that way. There is nothing "Harman like" here.
And thats totally valid since its your genuin subjective impression and a feedback, that I find rather interesting btw. To my ear while I certainly get far more bass with something like Atrium Closed or Abyss Phi TC, Caldera never felt bass light or lacking. The tracks that I enjoy for bass just slam. I read plenty of Calderas reviews by "professional" reviewers aswell as customer feedback, you Amir are the first person critizing the bass which makes me curious. May I ask which tracks you felt been lacking bass? And which pads been provided with your review unit?

In other news according to head-fi posts Zach cant reply to you since his posts are waiting for moderation approval ...
 
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