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Concrete Speaker Evaluation

samthebaam

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May 14, 2024
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I recently built some desktop speakers from concrete, and I am trying to understand my measurements.
I am quite happy with the overall sound, but they are definitely missing some base.

1715720212954.png




I am using a Dayton Audio DS135-8 woofer with a Peerless Tymphany BC25SC08-04 tweeter and crossed them at 1700hz in a sealed 3l enclosure. (Datasheets attached)

Below my far field on axis response measured at 1m
1715719768846.png


Here my near field measured response of the driver

1715719844787.png



1715719940622.png


How do I further smoothen the response and extend the bass? Do I simply need a sub?
This is my first DIY speaker so, excuse if there are any obvious omissions or mistakes.
 

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You can't expect much bass from a 5-inch woofer. And even if you tune it lower there's only so-much bass SPL you can get out.

Did you model the design with software and compare sealed & ported designs? (WinISD is free, or there are others.)

That bump between 100 & 200Hz could be a box resonance, or it might be the room...

Concrete seems like it might be a bit heavy for a desk or shelf. ;)
 
So I'll have to build my compact concrete isobaric sub that I have been conceptualizing.

Looking at it now, I think I may want to bring the upper end of the tweeter up a bit more to compensate for the baffle step.
Yes I used VirtuixCAD to help design the crossover.

My goal is to get to 50hz. I thought I would manage maybe 100hz with just the speakers.
 
As long as the woofer is not nearing its excursion limits, you can use EQ to improve the bass response.

I'd try extending the response in 10Hz steps (with a steep roll-off below) and listening for first signs of woofer breakup during music.
 
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Welcome to ASR! This is a very visually appealing / interesting build, nice work on that and thanks for sharing.

Doesn't look like you actually lost much bass from raw driver to in-cabinet.

Sealed this driver has an F3 of 113hz, so I think things are basically working as expected here. With a reasonable but not crazy xmax of less than 5mm, I am not sure you can get massive bass out of this thing no matter what you do, but I would *guess* you could get it flat down to 50-60hz at reasonable SPL without hurting anything, using EQ.

Either way, I would definitely suggest adding a sub. In fact, even if the bass response from this looked significantly better, you could still benefit from a sub. A sub is important not just to get low extension, but to add a second (or third, or fourth) physically separate source of low frequencies to fill in nulls from room modes.
 
@kemmler3D Thanks for the kind words.

I haven't got much experience with EQ. Do I just use something like soundsource for mac?

I actually also want to build the sub. I think it will be a cool addition to the concrete family. Probably will take me a while to make it though.
 
I haven't got much experience with EQ. Do I just use something like soundsource for mac?
SoundSource would work fine.

You can use REW's EQ function to generate presets and export them as .txt, which can then be imported into SoundSource.
 
@kemmler3D Thanks for the kind words.

I haven't got much experience with EQ. Do I just use something like soundsource for mac?

I actually also want to build the sub. I think it will be a cool addition to the concrete family. Probably will take me a while to make it though.
I think you might want to look into a MiniDSP unit or something, they're very commonly used in active / DIY builds. You can also do it on your computer, although I don't know of great solutions for Mac, I mainly use Windows, I think Soundsource might work but others can give you better advice.

If you aren't already on DIYAudio.com, the crowd over there is heavy into building speakers and could give you a lot of detailed advice on how to get more bass from this thing.
 
Neat project, do you want to share the building process?
I played a bit with concrete too on subs, but the damn’ thing ended near 200Kgs, it will stay where it is... How heavy are yours?
 
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