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Free / $29

SplineEQ has an average user rating of 4.50 from 12 reviews

Rate & Review SplineEQ

User Reviews by KVR Members for SplineEQ


Reviewed By jrucks01 [all]
June 24th, 2014
Version reviewed: 7 Pro on Windows

Well, a quick disclaimer and background before I start my review of SplineEQ. I had never heard of SplineEQ until today when asked to provide a review and my thoughts on the plugin. My mixing skills are adequate and continually growing and the opinions are solely mine based on my experience with the product. Now without further ado my review of SplineEQ.

SplineEQ was a completely new type plugin for me. I have only used a handful of EQs and mainly the stock PreSonus ProEQ (awesome by the way) and Waves Q10 & Renaissance EQs. There are more EQs in my arsenal but I usually stick to those that I know for mixing. Either I have had my head in the sand or just never caught up with the difference between phase and linear EQ - branching out during mastering EQ was using my Waves V-series EQs (I know rookie moves). However, having used the SplineEQ on a quick little ditty I threw together tonight my eyes have been opened in a shock of my ignorance. I will provide links to my examples using SplineEQ and same example without SplineEQ. But first my thoughts.

- any boosts and cuts need to be in moderation, but this plugin for some reason was very intuitive for me.

- use the provided presets for examples and starting points, I used the preset for the track and then adjusted to my liking and then saved for later use.

- the analyzer graphics are astonishingly useful; I prefer graphical analyzers in my EQ plugins and yes I use my ears but like having my eyes helping out.

- the only con is the CPU usage which is adjustable but never over the top in my limited experience.

The short track I recorded for examples consist of the following:

1 acoustic guitar (capo 7th fret) with a non-capo acoustic guitar accompany; bass; electric guitars; and Slate Drums 4 separated into channels for mixing.

Acoustic guitars both used my modified SplineEQ preset 'Acoustic - Bright and Balanced'

The electric guitars had a SplineEQ preset I modded 'Electric - smooth'

Bass guitar had SplineEQ modded preset 'Bass -12db limit for kick mix'

Snare used the preset 'Snare - 1' with a minor high-mid boost for rim shots.

Kick used the preset 'Bassdrum A1' with minor tweaks to remove the boxiness.

The drum bus had my FX chain preset of 1. PreSonus Pro Eq 2. IK Multimedia Black76 3. IK Multimedia Vintage 670.

Master bus had my normal setup of 1. Slate VCC 2. NI Bus Compressor 'Mix Glue' preset 3. Slate Tape Machine 1/2"

Each track has Slate Tape Machine and Virtual Console inserted before SplineEQ.

Here are the two examples:

First the mix without the SplineEQ: https://soundcloud.com/jrucks01/example-no-splineeq.

Now with SplineEQ: https://soundcloud.com/jrucks01/example-splineeq-active.

My take is that the SplineEQ gives each instrument its own space and allows the sounds to mix better. Having only spent several hours with SplineEQ I can already tell it will be a new go to weapon in mixing for myself and clients. Please let me know your thoughts on the review and thank you for reading.

*SplineEQ is currently selling for $19 until July 5th according to the website, so don't hesitate to buy. Low investment, big return in my view.

J. Rucks.

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Reviewed By solidtrax [all]
December 27th, 2012
Version reviewed: 1.09 on Windows

A lot has already been said about this amazing EQ, as there are currently ten reviews already here on KVR. For me, it's not a surprise so many people are raving about this plugin, as I believe this one is unique in both sound and handling.

Let's start with some basic information. SplineEQ is a linear phase equalizer plugin. This means that it does not change the phase of a sound, and as a result, gives a more natural sound. All this comes with a price however, because a little bit of latency will be introduced. As I'm using this EQ mostly as a master EQ and a few instances during mixing, I'm not complaining about this latency, I'm more than happy to pay this "price" and get an amazingly good and natural sounding EQ for it in return.

An unique approach
When we look at EQ plugins like Sonnox EQ, DMG Audio EQuality or Duende X-EQ, we talk about parametric EQ's. This type of EQ is what most people are very familiar with. They often have a fixed amount of bands that include high and low pass filters, high and low shelving filters and bell filters. When you take a look at EQ plugin like the Waves API 560 or Voxengo Marvel GEQ, you will easily see they are different, and these are known as graphic EQ's.

When we take a look at SplineEQ, we will find it's not exactly a parametric or graphic EQ as we have come to known in the last few decades. So what is it? Well, it's more a parametric EQ than it's a graphic EQ, that's for sure, but you won't find the high and low pass filters, shelving filters or bell filters in this plugin. SplinEQ uses a very unique approach to making curves and it's called Bézier splines. SplineEQ gives you the ability to design your own curves. The retail version ships with up to 60 bands so your imagination is the limiting factor here. This way of shaping a sound might take a few minutes to grasp, but once you understand how it works, you will probably love it as much as I do.

An unique sound
This EQ being unique in the way it's working, that is something that we have established so far, but I have not said anything about the sound. Ladies and Gentleman, that's because I wanted to save the best for last. This EQ sounds amazingly transparent. You will not find any analog buttons, hidden tube emulations or anything like that in this plugin. The only thing this EQ is doing for you, is shaping the sound with a transparency that is breathtaking. Adding a few db's and cutting a few db's with a standard digital EQ often result in a sound that somehow sounds like it's been altered. It's like you hear that there is an EQ on top of the sound. With SplineEQ, it's like the sound has been changed from within, and the result sounds as natural as it sounded before. Of course there is a limit to this transparency and we hopefully all understand that boosting 30dB around 5Khz on a full mix will most likely give a very unpleasing result, but this has nothing to do with the EQ plugin, and all to do with the person behind the knobs doing something very weird.

SplineEQ in use
During the mixing process I do use SplineEQ when a sound needs fixing, or in other words, when my normal go-to mixing eq's don't have the precision to fix a problem. For example, a kick drum that is recorded without a lot of body/low energy. With SplineEQ I have managed to make a kick sound powerful and punchy again by adding and cutting more than a handful of dB's at some critical frequencies while sounding totally natural at the same time. The difference between the kick drum with and without EQ was nothing short of a miracle. I asked some friends to listen to the difference and they couldn't believe at first that this was the same recording with just some help from an EQ. Countless of times I used the help of a transient designer and compressor together with different eq's to fix this type of bad, lifeless recordings, but with SplineEQ, I managed to fix it quicker and better without the need for other tools.

Another example of a recording that needed to be fixed was a lead vocal that was recorded in a very tiny room with a crappy microphone and no room treatment at all. I was able to remove a lot of the resonating (boxy) sound of the room without destroying the rest of the sound. Again, the end result sounded very natural and the difference compared to the original sound was stunning. I tried a lot of other EQ's to do the same, and although I was able to get very pleasing results with another one of my favorite clean EQ's, in the end, I preferred SplineEQ. I don't like mixing bad recorded songs, but SplineEQ makes my life a bit easier when the client has no intention of delivering a better recording.

When mastering, I love clean/transparent EQ's and this is where SplineEQ shines! It's probably not a surprise that it has become my favorite mastering EQ. When I'm mastering a track I always (try to) respect the mixer engineer, so I always try to keep the character of the track the same, while at the same time, making it translate as good as possible on many different devices. With SplineEQ, I can fix certain frequencies with an incredible precision. I have been able to master tracks with this plugin that normally would have needed a new mix. Having said that, I still prefer a new mix that doesn't need this kind of fixing, but sometimes there is no money/time and SplineEQ can really save the day.

In my opinion, SplineEQ is an amazing plugin. The way you can shape the curves and the way it stays transparent even when boosting or cutting a pretty high amount of dB's, is both unique and impressive. I'm confident that this EQ will find it's way to most of my future mixing projects and all my future mastering projects, just like it has done for the last couple of months.

For $19 this EQ is a steal. To be totally honest, I don't know what the developer must have been thinking when deciding to sell this plugin for so little money. In my opinion, it's on par with the very best there is on offer in the digital domain.

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Reviewed By Feng [all]
November 12th, 2012
Version reviewed: 7 on Windows

Brief description

Making eq curves with Spline EQ is really simple and fast. You have a large x-y plot with frequency on x axis and gain on y axis. On the background there is a quite unorthodox spectrum analyzer. it doesn't show Fourier transform of incoming sound nor shows spectrogram, but it uses a different approach. It shows you frequency bands as vertical bars (using the x axis reference). This bars become brighter as more energy is detected in their frequency range, they become darker and disappear when low energy or no energy is detected in their frequency range. You can watch simultaneously the unaltered spectrum (below the eq curve) and the spectrum altered by the eq (above the eq curve).

The overall graphic effect is very pleasing. To draw your curve you simply enter a number of frequency centers (yellow spots, created double clicking on the desired frequency position) and drag them to set the gain at that frequency. On the sides of the yellow spots a blue and a red one are there to define the slope of the curve.

You can also control frequency, gain, slope by three knobs on the right.

As all linear phase eq, Spline EQ introduces some latency, that's clearly reported on the GUI. A knob called precision lets you set how many filters will be active. At lower resolutions the eq cannot always match the curve you draw, so it lets you see the real eq curve in form of a dashed line. Clearly latency issues grow with higher precision values.

Spline EQ in action

The gain possibilities are amazing. I never saw anything like that. Each point can have a gain varying between - infinity to +60 dB. It is that you can completely mute some frequencies and highly enhance others. I tried Splne Eq on all kind of sonic material: overall mix (where liner phase eq tend to be used the most), but also drums, male voice, female voice, guitar, synths, strings and I have to say that it really does a good job.

Nonetheless I feel that SPLINEEQ strength lies in some more unorthodox use of its enormous power where it can really stand out

1. You can easily use it to extract or mute single instruments out of complete mixes,

due to the very very extended gain. Obviously it works best with instruments that have a quite narrow frequency spectrum. In a complete mix I was able to extract without many problems the kick drum, the bass, the cymbals and some midrange synths.

2. You can apply juicy frequency sweeps

There's a knob called "transpose" that, when moved, shifts all the curve to the left or to the right. Given the fact that almost any parameter can be automated I found myself drawing a "transpose" automation for a synth applying a very complex curve (that I would have never been able to create with the synth's internal filters).

3. You can easily cut away fixed frequency noise

I tried with some hum noise that I could easily cut without altering too much the other frequencies. the same applies for hiss.

4. You can create mind blowing, never heard effects

As I said almost any parameter in Spline EQ can be automated, so I tried to make some "extreme", experimental automation on vocal lines. The result was quite good. I could easily create wobbe effects, telephone like FX, and morph between them.

Obviously, due to latency, these tasks have to be programmed. Real time automation works fine only at lower resolutions.

CPU usage is very very low, expecially when thinking that this EQ is linear phase.

So the keyword in Spline EQ, in my opinion is POWER. While it can do a good job at subtle enhancements or at muddiness removal and at all standard uses, it really shines when used at full power, in more creative and unorthodox ways.

I think this is a very good plugin and, at 19 $, it's a REAL STEAL!

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Reviewed By Brother Charles [all]
August 2nd, 2012
Version reviewed: 7 x64 on Windows

** UPDATE! **

It seems that every time I need to perform any kind of surgical EQ tweak, SplineEQ has become my absolute GO TO plugin. Need to cleanly edit an acoustic upright bass track to retain rich sound while lessening "string buzz" or "click"? SplineEQ to the rescue. Need to bring out the 'shimmer' of a Hammond C3/Leslie combination? SplineEQ to the rescue. Need to tweak that nasty 'reverb ringing' in an otherwise nice vocal track? You guessed it! SplineEQ is a must have. Once you get accustomed to working within it's color-coded graphics assisted environment, your ears will become better trained (visual & auditory mental associations) and you can easily *find* offending frequencies.

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

Mr. M. Rouzic (aka "A_SN") contacted me back in the middle of June, 2012 and invited me to test and review his wonderful new Linear Phase EQ plugin, SplineEQ. I was honored that he thought well of my writing skills and audio engineering skill. Of course, I didn't apprise him otherwise. *wink*

I'd been very busy with work, ministry engagements and an overdue (3) week vacation and finally, at the end of July, 2012, I was at liberty to bench test SplineEQ. My findings are most nearly all positive. I will attest to my fellow KVR reviewers' testimonials that there can be quite a bit of latency induced if you operate this plugin at its higher quality settings. That aside, it does sound very, very clear and free of ringing, fuzziness, or other fatiguing audio artifacts. As such, this plugin shines brilliantly in a final mix/mastering scenario.

By default the full version gives the user (5) key frequency centers - 80hz, 253hz, 800hz, 2.5khz, 8.0khz. You can add as many frequency bands as you want from there, by simply double-clicking at an insertion point of your choosing. I've gotten into the habit of adding 42hz, 32hz, and finally 20hz bands to create smooth, downward-sloped low frequency cuts. SplineEQ is a great tool for cleaning out unwanted low end muddiness. The low end spectrum isn't "hauled away" with conservative use; it just gets cleaned up and balanced out. Once you add a good mastering limiter to the end of the mastering chain, you'll get the "oompphh" back on the bottom end, but it will sound clean and articulate. This process has kicked the quality of my final mixes up a couple of notches. I used to rely of Bootsy's BaxterEQ for this - SplineEQ does yield even cleaner results.

What particularly impressed me about this EQ plugin was its wonderfully CLEAN sound quality. The EQ curves are very smooth; even when adjusted in steep, narrow bands. SplineEQ's tonal shaping qualities are easily adjustable in very granular steps or in large swaths. Yet, the audio quality remains high and transparent. I like to describe this plugin as a 1st class tool to realize accurate and extensive tonal shaping without "coloration" or audio graininess.

This plugin is attractive and offers a nicely sized interface. I won't discuss these features as they were well-reviewed by Monk_Volcano previously. I agree with Monk_Volcano's comments on the gui design and that the vertical color-coded analysis bars greatly aid in locating "troubled" frequencies.

On a recent CD track for my upcoming Gospel album, I used Spline's lower resolution settings to make Acoustica's Pianissimo (Steinway Model D sample VSTi) really come to life, without noticeable latency, and without losing the warmth and character of the classic "Steinway" tone. When played at higher velocities, Pianissimo does somewhat over-accentuate sympathetic resonance and upper register "ping". When played at lower velocities, Pianissimo tends to become a little too "dark/mellow" sounding. Nevertheless, it really is a remarkably good sounding piano VSTi and it competes very well against sample libraries costing 2 or 3 times as much. By lowering the velocities of louder notes and enlisting SplineEQ as an insert effect on my piano track, I was able to balance the tone of Pianissimo to sit in the mix perfectly. It retained the warmth without sounding "boxy" or dull. The piano's upper register rung though cleanly and pleasantly without any shrillness. The mids were tamed nicely without losing definition.

** EDIT **

Using subtle high frequency increase @ 2k, 4k, & 8k (+1 dB, +2.4dB, +2.1dB respectively) made my favorite B3 VSTi absolutely come to life and "shimmer" with gorgeous, breathtaking clarity. We are talking about taking the sweetness of Gospel-style Hammond Organ "through the roof, people!" - SplineEQ used as an insert plugin in this instance. The VSTi in question? Genuine Soundware VB3

Any time I attempted to "fine-tune" Pianissimo (and some other VSTIs) using conventional (minimum phase) Parametric EQ or classic multi-band EQ plugins, I would sometimes hear slight grainiess or fuzziness on some note tails and decays. This issue has been entirely resolved for me since I started using SplineEQ.

I don't own FabFilter Pro-Q, EQuality, or any other expensive Linear Phase EQ plugin, but I can tell you this - SplineEQ is an amazing plugin that allows tremendous control over tone-shaping. It's very simple to use, largely due to its intuitive, attractive interface. If you don't presently own a high quality linear phase mastering EQ, I can guarantee that your mixes will benefit greatly by purchasing and using this professional, studio-grade plugin.

I rank SplineEQ way up there with other exceptional products such as ToneBooster's TB Barricade (Brickwall limiter), Klanghelm's DC8C (Compressor/Limiter), MeldaProductions VSTs, HollowSun samples, etc.. .

Yes, it's very, very good. It's also very, very reasonably priced.


Attractive design.

Clean, transparent audio quality.

Ease of use.

Capable of extensive, equalization fine tuning.

Granular control (when needed).

Very affordable.


Latency - it is linear phase after all. This type of plugin is best suited for mastering purposes.

When attempting to change resolution settings, during playback, it has caused my DAW to stop responding. I'm using Acoustica Mixcraft 6.0 b194. Otherwise, the plugin is very stable.

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Reviewed By monk_volcano [all]
July 18th, 2012
Version reviewed: 10.6.8 on Mac

I told myself I would really try not to give this plugin a 10/10. But I have to. I'm sorry. I guess if I could, I might give it a 9.5 because there are just a couple of minor features I would like to see added, though they would just be some icing on this cake. When I first read about this plugin, I was thinking "ok cool, a linear phase eq with a nice interface, every one needs one of those lying around." I came to find out that there are a handful of features that take this plugin to a higher realm of function. This is freaking great plugin that has as many creative uses as it does practical.

I'll start with the sound. The sound is what you would expect from a linear phase eq, I reckon. The clarity that the signal retains when making enormous boosts is pretty stunning. Even while making extreme boosts to very high frequencies, it sounds as if the filter is simply making those frequencies louder; any distortion or artifacts created are virtually indistinguishable to my ears. This allows you to radically alter sounds, and still retain a lively sound. It's really crazy what you can get awaywith on this thing. Considering that I'm into "idm" (it's ok if you roll your eyes), this is very exciting to me.

One of the key elements that gives this eq a unique set of qualities is the usage of Bezier curves for the band filters. I mathematically have no idea what that means, all I know is that it makes working with this eq notably different from working with a standard parametric. It will take a little bit of getting used to, and I'm guessing there are some situations that it may not be preferable. You can have from 1-60 control points, and this is more important than you might think. (This next part is going to be tricky to explain, but I'll do my best.) First of all, when you boost a node, the bandwidth of the boost is altered depending on its proximity to other nodes. In other words, if there are other nodes close by, they will make the bandwidth of the boost smaller. In addition to that, changing the slope of a filter band doesn't have the same effect as changing the q in a typical eq. When you raise the slope amount, higher frequencies will be boosted and lower frequencies cut, when you lower the slope, the opposite occurs. This can yield very "musical" results. I know it sounds complicated, but I'm sure you'll catch on quickly if you give it a spin. I find working with these curves to be very easy and effective. Also, I just find it very enjoyable to explore a novel approach to eq'ing.

Then there are some even more out there functions which really end up making this plugin for me. The transpose function allows you to shift all of the control points up or down the freq spectrum. So basically you can make a crazy filter and this is the cutoff control. I should add that adjusting this parameter occurs perfectly smoothly; you can automate the hell out of it. A very powerful feature. It also has other uses. For instance, let's say you've transposed a synth line up a few semitones, but you want it to have the same "spectral signature", transpose the eq up as well! Then theres the 'gain scale' parameter. This controls the overall amount (or scale, derp!) of gain boost/cut. Often I'll go a little overboard with this eq, so this parameters is great to reel it in a bit while maintaining the tonality I've achieved. But we're not through yet.. by using negative values, you can invert the amount. HECK YEA! This is a quick and dirty way to separate two clashing elements. In studio one, I can apply a little boost to one signal, and then just copy the instance of splineEQ over to the sound its competing with, invert the gain scale, and BAM! no more masking. Maybe a bit of a ham handed way of doing it, but it works really well in certain situations!

Last but not least: the GUI is gorgeous and functional. For some reason when I think of linear phase eq, I think of some big gnarly laggy beast of a plugin that requires me to put on a lab coat to operate… err, maybe thats just me being a bit over dramatic I dunno. Whatever the case, this plugin is elegant and responsive. The rainbow frequency analyzer in the background will keep your girlfriend mesmerized for hours while you tweak your "keyboards" in a state of euphoria. Besides that, it simultaneously displays the spectral content before (bottom the eq curve) and after (above the curve). I also just find it easier to see what frequencies are present with this style of analyzer.

OK and a couple of relatively minor critiques. The range of this thing is huge. By that I mean, you can make up to 60 db boosts. It might be handy to limit the amplitude range for when you're doing more conventional equalization duties. Another idea that struck me, is the ability to lasso groups of nodes and move them about together. Given the shear number of nodes available, this could be very hand.

So basically this thing is fantastic. If you are doing any sound design heavy music, I'm on the verge of telling you this eq is a must have, even though I generally try to avoid saying that about anything.

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Reviewed By bduffy [all]
May 29th, 2012
Version reviewed: 1.0.9 on Mac

This is quite an extraordinary EQ. I'm usually not crazy about Bezier curves (even in Adobe Illustrator, they drive me mad!), but this EQ gives me an excuse to get more familiar with them. But I do have to say, the "killer app" with this EQ is the amazing spectral display.

The RGB display undulates and moves with the audio signal (red = low end, high = blue, as expected), making it very easy to zero in on hot spots in the recording. I was able to instantly remove the boxy character from a tricky voiceover in a mixed ad spot, while leaving the background music largely unaffected, just by adding a generous dip around the "green" area, which was clearly the VO's fundamental area.

There are some great tricks here too, like being able to transpose and adjust the gain of filters. The limiter is a nice touch, although it doesn't seem to protect the signal from distorting at all. It may need another tweak or two, but generally, I would never boost enough to make my EQ scream, so this is not a big deal.

Another con: there does not seem to be a way to bypass a band; you can only create and delete bands, which seems a little destructive for the sensitive art of mastering.

Also a great feature: you can control how precisely the EQ follows the "ideal equalization curve". At lower values, a dotted line will show how much the actual EQ is diverging from the ideal EQ, and you can increase the precision to more closely match the "ideal". I could use it a highest quality in Wavelab 7, no problem, but it sounded good even at lower settings.

Overall, this seems ideal as a mastering tool, given its buffer sizes and CPU use. Again, it's easy to find trouble areas in your mixes with the display, and the curve splines can give you very precise control over the signal, or even offer a novel way of approaching EQ. At $19, this is a crazy steal, and there's a 4-band version, which could already meet most mixing/mastering needs. I strongly advise readers looking for a cool linear-phase filter to check it out.

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Reviewed By jam92189 [all]
May 6th, 2012
Version reviewed: 1.08 on Windows

The best eq for audio restoration I Have ever used

I have used this eq for about 6 projects now 3 audio cleaning for a podcast of a good fiend of mine and 3 for use of the master mix of some classical guitar of some guitar students.

I'm going to start with this. The eq will lag up like crazy when you have this set to maximum. that might sound like a problem but its not. This thing is so amazingly transparent i have been able to get rid of hum and hiss with just this eq alone and still keep the tone of the voices. what i do is is set the delay to minimum when i am picking frequencies to cut. Honestly to me you almost cant tell the difference between the sound of different latencies its always amazingly clean and clear. But I set it back to max just to have the most effect when i cut. besides that i like how when you change the resolution of the eq it shows what I like to think of as the true band of the eq always nice to know what the difference it but still very smooth and clean.

The analyzer at first before I used it I thought might not be useful but i have to say its almost like a frequency analyzer that is set to show you how much the frequencies are cutting through. Its super easy to read and i love how it has helped me find frequencies that are standing out a little to much.

The way that the eq bands work at first might be a little odd to get to know how to use. Once you play with it for a little bit you really get why its done the way it is. i have been able to set it like a hum remover or style it almost like a pultec style eq. I really like how i have full control of the curve in every way.

overall this thing looks nice, the features are really easy to figure out and it sounds just amazing. I have replaced my audio cleaning plugins with this because i find i can get the results i want with this a lot faster and cleaner sounding. As for mixing I personally chose to use this as a mastering tool but with minimum latency you can still have high resolution and use it in a mix when you want some linear phase eq on parts.

as for mastering i have it set up to be with my specter from sknote. i find both of them working together really gets the job done in a quick easy smooth way. overall i would say this is one of those rare gems that really needs to be looked at and given a lot more praise than you would think. The price is amazing when you want the ultimate linear phase eq with total control of the whole eq curve of the way it will use i would say spend the 19 bucks and get this baby

the only negative i can think of is that the brick wall limiter part kind of distorts easy. I don't have to worry about that personally because i mix at good levels and when I record or get mixes form other people i try to get them at good levels besides that i would say its a great tool. If anything would say just put more of a transparant limiter on the end and this thing would be perfect. I am going to be using it on my projects that have any audio cleaning from now on though.

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Reviewed By Sendy [all]
April 19th, 2012
Version reviewed: 1.0.7 on Windows

SplineEQ is a linear phase EQ with an innovative GUI which combines spline curve editing with visual feedback and just a handfull of the most essential features, plus a few generous extras.

Firstly, I'm no expert on EQs, but it sounded very transparent to me, even in the treble end. I'm ready to believe that when I push the treble up with this EQ, what I'm getting is simply a louder version of those frequencies I've chosen to accentuate with the curve profile. This makes it perfect for corrective EQ or other situations where surgical precision is required. Bands can be as narrow as you like, have any steepness at their transitions, and you can boost, or completely take out an exact band of frequencies to silence.

The plugin will introduce latency (which I believe is a neccecity due to the time-critical nature of linear phase EQing), which was automatically compensated for by my DAW, but could lead to problems in a live situation. But then who EQ's stuff in realtime? The latency can be traded off for less filter accuracy, which doesn't degrade the sound quality, but does degrade the resolution of the filter curve. Where the curve deviates from your programmed profile, a dotted line shows what's really happening. In most cases I've found it's low frequency resolution that is lost with the trade-off, but unless you're doing surgical bass work, this isn't going to be much of an issue and moderate settings give good results.

Creating and modifying curves in the GUI is a breeze, and the visual feedback really makes this EQ stand out. The input material's frequencies are shown under the curve as pulsing beams of colour-coded light, and as they pass through the curve, they get brigher or dimmer, or completely disappear, depending on how much the curve deviates from the neutral setting. Not only is this a really intuitive concept visually (and quite pretty), but the way the frequencies are depicted is somewhat different to the norm, and I found it very natural and a good way to picture the frequencies in my music.

Finally, the extra bonus functionality here is the option to shift the filter response up and down the frequency range - right off of the screen if you want - and alter the magnitude and even polarity of the curve, so that peaks become troughs, etc. This feature allows the creation of some serious creative filter and phasing effects, and the brickwall resonant lowpass filter I constructed sounded very fat and dare I say 'punchy'. Seriously, I couldn't stop squelching my mix with it :)

I can see this getting some serious use as a creative filter as well as surgical EQ.

For the low price, there is quite a bit of functionality and usability packed into SplineEQ. If you've never tried a linear-phase EQ (as I hadn't) I recommend you give the demo a shot.

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Reviewed By myk [all]
March 3rd, 2012
Version reviewed: 7 (x64) on Windows

First off, it is pretty awesome. The gui is slick, styled well, and original. Also, the concept of Spline EQ is fairly amazing. I have always had a blast playing with Vector Graphic programs like Illustrator and Inkscape where you can drag nodes easily and fluidly, and to be able to control eq levels that is way is seriously fun - it opens up possibilities that - while the techniques to produce the sound in question were never not there - suddenly reveal themselves with astonishing ease. The differences are extremely noticeable as well - there is no need to be concerned with whether or not something is too subtle for the equipment you are using. This is not to say subtly cannot be achieved here, it is just not the only game available. All in all, the sound are interface are a 10/10, and are of the level of professional quality plugins (the few that I have used anyway).

Why I will likely never use this in a true production situation:

The latency is a killer. Something like 49ms on my computer (my very fast and powerful computer), and the compensation required just isn't worth it. I don't know enough about DSP production to have any sense of what the source of increased latency is, or why it might not matter as much as think it does, but until that gets fixed, this is essentially unusable for me. I've only used two plugins in my life that caused latency that was immediately, and unmistakably audible, and they were both great plugins; but they damaged the mix so much that I can't compensate for it in my listening.

Bottom line: Killer plug-in. Too much latency.

Developer edit: Have you noticed the knob called Delay? You can use it to bring the latency down to about 17 ms. If you're willing to compromise on resolution you can even bring it down to about 6 ms. Every linear phase equalizer introduces delay, at least SplineEQ allows you to adjust how much you get as a trade-off between CPU usage, latency and frequency resolution (and it remembers your settings permanently). It can't get much better than that for linear phase equalizers, which makes your comments and rating sound like a misunderstanding. Furthermore as someone else pointed out the main use for linear phase equalizers is in mastering and final mixing.

User Edit:In taking the developer and other user responses into consideration, I have revised my rating. I do think this is a d*mn good eq. However, I have used linar phase eq's that don't introduce noticeable latency, Voxengo and Electric-Q to name a couple. I am no master in the music production field, and as I said, I don't know why the latency is introduced or why it might not matter, but it still is what it is. I will play with the delay some more. When using it the first time, I found that the latency was not improved by as much as you say, but I can't remember exactly. Still, if I can get it below 10 or maybe even 15ms or so, for sure it would be at the top of my stack.

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Reviewed By RickardTheGreat [all]
March 3rd, 2012
Version reviewed: 7 on Windows

So I downloaded Spline EQ and threw it in fruityloops. It was really easy to set up. After that I messed around with it and changed each one of my drum tracks. I used some preloaded settings that are grouped together with Spline. They made everything a lot easier for me to get a better sound out of the drums already included with FL studio.

Besides all the preset settings its easy to change the sound to tweak it in your own way by messing around with the curve. The colors in the program interact with the way the curve is moved and it is really easy to hear what you are changing in the sound as you go as well as visualize it. It is also easy to save your settings so that its convenient if you want different instruments tweaked the same way. I enjoyed using this plug in a lot.

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Reviewed By FarleyCZ [all]
February 22nd, 2012
Version reviewed: 1.0.5 on Windows

Once a while, when mixing and especially when sound desigining, you come to the point of: I wonder, what it wold sound like if I applied little ramp shaped EQ response with crazy steep end. Or: What if I just grab this band strictly from frequency to frequency and low it down?
...and such. Problem is, that you have no chance to do it. Classic parametric EQ offers you lots of sound shaping but responce is not so chirurgicaly precise as you'd need.

Developer of this plugin told himself in this situation: Naaah, I'll do my own EQ for that. ...and he did. And it sounds awesome.

One may say: So what? But think about it really...It's not that easy. EQ's as far as I know are bulit either by DSP (sometimes analog) filter modeling or by some FFT mangling. Nature of this idea kinda excludes any other then FFT way, so they needed to concentrate on that.

Now I don't know about you guys, but my expirience with FFT is kind of bad. These plugins always contain qualitty setting that sets length of window that plugin operates on. I often get wierd sound artifacts or "not so sharp" sound when turned down. This EQ? None of it, sounds absolutely cool even when qualitty turned to lowest. (Low and too steep filters loose a bit of definition when qualitty is set to low, but you're informed about it in very pleasant and non disturbing graphical way by "alternative curve".) Whole sound really tells you they have lot's of FFT expiriences from Photosounder.

One thing that's really a question is: How do you tell if it sounds good, when concept is so new? Well I don't know, but what I can tell is, if you draw some really crazy curve, it doesn't sounds harsh, aliased or with digital artifacts, but like some equally crazy sound alternation you hear in wierd nature conditions. And that is good. Really good.

I can also imagine it could be amazing for fixing these responses on recorded material while mixing. When something sounds like from coffe cup, it could be pretty nicely cured by exactly that ramp I described at the beginning, just inverted.

It has bad sides of course, every plugin has. Firstly, for casual mixing, it could be bit of overkill. Especially when some slope shaping demands two filters to model (in vector-spline way). Secondly, few more curve handling functions would be nice. I can imagine shift of selected filters or free hand drawing whith automatic filter position solving. Point down for that, but just as a little cheeky motivational poke. :) On the other side this "whole reponse shifting" is feature I'd like to see in some other EQs. :)

All and all this is really a breath of fresh air. Amazing for experiments and in some specific situations it can really save your ass I guess, becouse classic EQs could be too solid for some tasks. Sound is pleasant and without a single problem. Not you'r bread and butter EQ and handling could be still a little bit improved, but really fresh little plug.

Me recomend really much! :)

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Reviewed By Syrou [all]
January 13th, 2012
Version reviewed: 1.0.3 on Windows

Incredible easy to use, with a near to no learning time at all. It does well for mixing
and allows you to quickly see those frequencies you want to either boost or cut.

I've always wanted a quick way to separate different instruments in my mixes.
With this tool, you have a function called Gain Scale, which allows you to invert
the settings you made for one instrument, so that two frequency-ranges never are exactly the same.
This helps alot when you are trying to isolate instruments from eachother in the mix.

For me this EQ is definitely a must have in your studio setup.

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Latest 12 reviews from a total of 12

Comments & Discussion for Photosounder SplineEQ

Discussion: Active
4 March 2012 at 9:09am

@myk: I haven't used SplineEQ, but as I understand it, EVERY linear phase EQ introduces latency because of the way linear phase adjustments are computed (the signal must be delayed a bit, kind of obvious if you think about it). That's why they're typically used for mastering and final mixing, as opposed to tracking. Seems kind of unfair (if not dead wrong?) to mark it down for something that's inherent to its way of working.

5 March 2012 at 9:23am

@myk Just locate the latency knob and adjust it for lower latency, you should be just fine.

The reason why you want to be able to change latency, is for rendering purposes. If you are really anal about getting the best possible sound, you should increase the lantency when you render, and that will give you an even sharper sound. As you might have noticed with the "dotted real processing" line that shows up on the lower frenquencies,

it will become more accurate with higher lantecy settings, this is something you can't escape when processing audio the way linearphase eq's does it.

It's not fixable, it's just something you have to learn, with ALL linearphase eq's :)

5 May 2012 at 5:19am

just a little thing to say I tried this out on a audio cleaning project i had and it kept the tone of the voice but got rid of the noise I mean whistling right next to the vocal frequency. no other eq i had was doing it right and this baby kicked ass.

7 May 2012 at 5:43am

i use this for sound design and it is awesome

7 May 2012 at 6:03am

yea its a great plugin i love it

7 May 2012 at 6:17pm

Really nice free EQ, very tweakable, efficient and colorless. Perfect for cleaning, mixing and mastering.

7 May 2012 at 9:05pm

I agree. the paid version is even better to. I use this for cleaning and mastering

3 July 2012 at 7:23am

Yep, i discovered what the free is by itself capable of on a sample design purpose and after that i'll certainly by the full version ASAP ...really excellent tool !

3 July 2012 at 8:24am

You know what is awesome is if you set it to minimal delay and stuff right to find something like if there is this annoying hum then you cut the hell out of it swap back to max mode and render you will be amazed on how high the quality of the eq its like you never did anything but the hum is gone. its very non destructive

3 July 2012 at 9:36am

well i currently experience narrow bandpass (rather than bandstop) to isolate locust's stridulation at almost a precise frequency then rendering, not much different technique as you know, that what made me amaze about spline eq

3 July 2012 at 6:56pm

I know some people complain because its super latency ridden but that's what i think makes it so good the quality of the eq is so high that it has to be

Brother Charles
Brother Charles
12 November 2012 at 6:58pm


Great review. I like how you brought out more information about the unique graphically-driven features.

12 October 2013 at 4:53pm

Brilliant mastering EQ. Top quality.

28 June 2014 at 1:52pm

TOP notch EQ plugin right here..

Best delivered in final mixing master bus and mastering.

8 February 2020 at 7:05pm

Why no hpf/lpf filters?

8 February 2020 at 7:49pm

You have to make them yourself. Place a control point high and another low.

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