A simple inline DSP equalizer: is it possible?

[bachatero]

Hi everyone, I'm stuck in a weird position with an audio setup of mine.

I go to a gym which offers judo on a long foam mat, and we like to listen to music while practicing judo on it. On the other side of this mat is a fitness area of around the same size. Because I basically live for music, I decided to go all-out and drop some megabucks on some EV powered speakers and a TOTL subwoofer with each top facing the mat on either corner 10ft away from the side pointing inwards at a roughly 45 degree angle, and the subwoofer sitting at the midpoint. To summarize the rest of the setup, anybody can just connect their phone to a little Bluetooth receiver that supports either analog or TOSLINK output and play anything they wish.

Unfortunately, I get really annoyed because my favorite recorded music just doesn't sound right even at the acoustic sweet spot where I love to do exercises. Huge L. This is probably due to the EV speakers lacking a flat response curve and the gym being made of corrugated steel. Before joining this forum I scoured the web for days (actually weeks) looking for a simple and cheap solution to get PEQ and possibly a FIR filter for room correction. The constraints are:

• that it can't cost more than a couple hundred USD (due to the possibility of being stolen/smashed),
• that it should work with free and open-source software if required, and
• that it has to have inaudible distortion/noise (to prevent generational losses).

Here's what I found with some thoughts on each:

• miniDSP 2x4 HD: I like this one a lot! I like how it's simple and has a TOSLINK input for a direct BT receiver connection. I also like how it's relatively cheap at "just" $260 from Bezos Mart. I don't like how you need fussy software and a laptop, or a costly BT dongle if I want to use my phone. I don't like how the ASR review revealed some unsavory performance from the TOSLINK input.
• Dayton Audio DSP-408: I like this one too! I like how it's just as simple as the 2x4 HD. I like how cheap it is compared to all the other options. I don't like how it doesn't have TOSLINK. I also don't like how you need to get another costly BT dongle to use it with your phone, or laptop with fussy software. I don't like how it was just middling in the ASR review.
• miniDSP Flex: I like how this one just includes everything out of the box. I like how it topped everything else in the ASR review. I like how it could possibly be not much more expensive than the others due to integrating Bluetooth as both a controller and a receiver. I don't like how it's a whopping $575 for a version that would work natively with the speaker system (balanced outputs).
• Behringer Ultracurve Pro DEQ2496: I like how this is basically just what I needed at a fine price. I like how it supports TOSLINK. I like how you don't need any external device at all. I don't like that it's out of stock everywhere unless you pay highway robbery prices to a scalper. I don't like how its ASR review wasn't the rosiest regarding DAC performance.
• Thomann t.racks: I like how this one is super cheap, like only $100! I like how it's super simple. I like how it performed great in the ASR review. I don't like how you need more fussy closed-source software with a laptop, not even the option for a phone.
• Some Hifiberry Thing: I like how Hifiberry is straight up the hardware and free and open-source software, no extra funny business. I like how I have the option to have a web panel to access it from any device. I like how the DACs should perform well (hopefully). I don't like how I sold all my unused Raspberry Pi 4s last year due to them becoming a 200% yield investment and now I can't get any.

In short, I'm stuck in a quandary with all these options that each have some huge gotcha. Is there some hidden option I'm not aware of?

Thank you ASR!

 

[Zapper]

How about the WiiM (any model] which now have PEQ capability?

Regarding the ASR reviews, how good does it have to be when playing ZLX speakers in a corrugated steel gym? I imagine that the nits that Amir picks are pretty inconsequential in that context.

People lose perspective on the things that Amir measures. Maybe the difference between the best and worst DAC or ADC can be heard in a blind test by someone with very keen hearing in very good listening conditions. Most of us wouldn't hear any difference at all, even in optimum conditions. Probably no-one ever would hear any difference in your gym.

 

[gnarly]

Hi, my 2c is to get whichever device gives you the functionality and ease of use you desire.
(I only use the ASR SINAD etc reviews as tie breakers)

 

[bachatero]

How about the WiiM (any model] which now have PEQ capability?

I just checked out the Wiim Pro and it actually looks great. However, the one catch looks like that it hinges on WiFi, which is nearly incompatible with how we use the audio system with only Bluetooth and no specifics after that.

Regarding the ASR reviews, how good does it have to be when playing ZLX speakers in a corrugated steel gym? I imagine that the nits that Amir picks are pretty inconsequential in that context.

Truthfully, it probably doesn't matter that much for ZLXes in a steel gym. However, next year I'm planning on upgrading to ETX speakers and adding substantial acoustic treatment. Then it may matter a little more.

Hi, my 2c is to get whichever device gives you the functionality and ease of use you desire.
(I only use the ASR SINAD etc reviews as tie breakers)

I can get behind this. The one problem, though, is how even after discounting SINAD ratings, there still aren't many good options.

If worse comes to worst I might be in the position to just design my own DSP EQ because I'm in college for an engineering degree.

 

[Zapper]

I just checked out the Wiim Pro and it actually looks great. However, the one catch looks like that it hinges on WiFi, which is nearly incompatible with how we use the audio system with only Bluetooth and no specifics after that.

The WiiMs also work well as a Bluetooth receiver, and with analog and digital inputs. They are very versatile.

 

[dweeeeb2]

FYI Wiim Mini has bluetooth and EQ

 

[bachatero]

FYI Wiim Mini has bluetooth and EQ

I'm liking the sound of this. Looks like the Mini has full fat PEQ and is by far the cheapest premade option.

Looking at Hifiberry a second time, it turns out RPi 4 1GBs are in fact in stock again (https://rpilocator.com) so the total price of one of those would be 84.90 + 11.90 + 35 = $131.80 for a DSP board, case, and Pi 4. That's not much more moolah for something potentially a lot more flexible.

I guess what I'll do from here is see if improving acoustics can possibly help, and then see if a Wiim Mini would fit in nicely with the setup.

 

[MAB]

Have you looked into software DSP? For instance:

Equalizer APO

Download Equalizer APO for free. A system-wide equalizer for Windows 7 / 8 / 8.1 / 10 / 11. Equalizer APO is a parametric / graphic equalizer for Windows. It is implemented as an Audio Processing Object (APO) for the system effect infrastructure introduced with Windows Vista.

sourceforge.net

If you are playing music from your laptop, then this would be a super-quick way to check out if you can find a notch that will prevent the subs from driving your wall's resonance. Even if this isn't your normal mode of playing music in your gym, you could use a laptop with software to explore if DSP can help your situation. I think it can...

 

[bachatero]

I already have EasyEffects (like EAPO but for Linux) and use that at home, but we usually use phones at the gym. If there's a good PEQ app for Android then that would work for when I'm playing music there.

 

[Jimbob54]

I already have EasyEffects (like EAPO but for Linux) and use that at home, but we usually use phones at the gym. If there's a good PEQ app for Android then that would work for when I'm playing music there.

If tidal, qobuz or local files are your source, usb audio player Pro on android will allow peq over Bluetooth.

 

[ehabheikal]

I'm liking the sound of this. Looks like the Mini has full fat PEQ and is by far the cheapest premade option.

Looking at Hifiberry a second time, it turns out RPi 4 1GBs are in fact in stock again (https://rpilocator.com) so the total price of one of those would be 84.90 + 11.90 + 35 = $131.80 for a DSP board, case, and Pi 4. That's not much more moolah for something potentially a lot more flexible.

I guess what I'll do from here is see if improving acoustics can possibly help, and then see if a Wiim Mini would fit in nicely with the setup.

all wiims only have 4 peq rules which is not a lot. I see other systems have 10 rules

 

[MAB]

I already have EasyEffects (like EAPO but for Linux) and use that at home, but we usually use phones at the gym. If there's a good PEQ app for Android then that would work for when I'm playing music there.

I am clueless on Android apps, but seems there should be one.
Can you bring a laptop with appropriate connectivity to the gym just to investigate?

Also, you you can run test tones or sweeps to find the resonance, and even estimate the Q (~width) of the resonance. There are a ton of apps for android for this type of work. Just be careful not to blow a woofer! A sweep or tone is much easier to identify the source or sources. A subwoofer and tone generator is an incredibly good tool for identifying resonances.

 

[antcollinet]

I don't like how I sold all my unused Raspberry Pi 4s last year due to them becoming a 200% yield investment and now I can't get any.

PI4 shortages are ended now, and have been for some months. Should be readily available from stock in most places.

Even the new Pi5 is available in stock from my usual source.

Find Raspberry Pi computers in stock - rpilocator

Find Raspberry Pi computers in stock - rpilocator

rpilocator.com

 

[ehabheikal]

rasperry pi can do this but it is nom trivial installation and the eq process is also a bit difficult.

 

[bachatero]

rasperry pi can do this but it is nom trivial installation and the eq process is also a bit difficult.

What is the process

 

[ehabheikal]

You use rew to create peq using a specialcalibrated mic then using REW software to create the rules based on these measurements. Mind you REW has so many advanced usages that it us difficult to use.
Premade systems like dirac, yapo etc are easier to use. This makes even.more of a difference since everytime you change significantly your setup like moving subs or speakers.

 

[CedarX]

Low-end option…. Would something like a Hiby R2-II work? Yes, it’s a DAP, but it can be used a BT receiver (easily 30ft with line of sight), has a 10-band GEQ + Hiby MSEB kinda-PEQ, a decent DAC (ES9219), and is ~$100 (as low as $90).

 

[LIΟN]

I don't know that works for speaker... But I think it's possible. It also applies to using IEM with Bluetooth.
You can check Android JamesDSP(Rootless). It is applicable to all kinds of EQs and convolutions. If you don't have enough regular EQs, make your own EQs with a pir filter and put them in. Then it probably won't be enough. I don't remember exactly, but I think Jamesdsp supported up to 8192 or 16384tap.

 

[bachatero]

I don't know that works for speaker... But I think it's possible. It also applies to using IEM with Bluetooth.
You can check Android JamesDSP(Rootless). It is applicable to all kinds of EQs and convolutions. If you don't have enough regular EQs, make your own EQs with a pir filter and put them in. Then it probably won't be enough. I don't remember exactly, but I think Jamesdsp supported up to 8192 or 16384tap.

I just got JamesDSP running and it's looking promising. It looks like I can choose between a GEQ or convolution, either being a good option.

 

[LIΟN]

I just got JamesDSP running and it's looking promising. It looks like I can choose between a GEQ or convolution, either being a good option.

I'm glad you like it.