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.
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
Here my near field measured response of the driver
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.
I am quite happy with the overall sound, but they are definitely missing some base.
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
Here my near field measured response of the driver
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.
Sealed? For a 135mm woofer the response is OKish. Guessing without looking at the data or modeling the midbass...
Bigger box that extracts more from it, or reflex, or helper woofer.
Where are these measures being taken?
The near field measure should better show the actual bass extention. The bumps in the decay are likely from the speaker’s environment.
dave
PS: next one, get the tweeter closer to the midbass.
Bigger box that extracts more from it, or reflex, or helper woofer.
Where are these measures being taken?
The near field measure should better show the actual bass extention. The bumps in the decay are likely from the speaker’s environment.
dave
PS: next one, get the tweeter closer to the midbass.
The measures were being taken in a large room placed in the centre from the floor to the ceiling, and the response was gated.
So for the size of the speaker this should be an acceptable response, or is there more to be done except the bass extension?
Could you elaborate on the tweeter placement? Now that you mention it, most speakers seem to have the tweeter close to the mid-bass. What is the reason for this?
I guess I'll have to make the compact isobaric concrete sub to go with them then
So for the size of the speaker this should be an acceptable response, or is there more to be done except the bass extension?
Could you elaborate on the tweeter placement? Now that you mention it, most speakers seem to have the tweeter close to the mid-bass. What is the reason for this?
I guess I'll have to make the compact isobaric concrete sub to go with them then
Perhaps you could ease the size of the cabinet by adding some stuffing, making it behave as though it were larger.. however you can't expect much bass from the average 5" mid/woofer.
Since you will be sitting close you have the option of EQing the bass where you want it. If this overdrives it you'd want to consider adding a 'sub'.
Since you will be sitting close you have the option of EQing the bass where you want it. If this overdrives it you'd want to consider adding a 'sub'.
Like aircraft hanger large? You have a lot of resolution in your frequency response plot, which implies a very long window (gating). It's not a big issue given what you are describing and since your nearfield and 1 meter response trends are similar, but it does seem curious.
In an ideal world the drivers centre-to-centre distance will be less than a quarter wavelength at the XO frequency.
since this is practically impossible, my rule of thumb is get them as close as possible… even to the point of trimming the tweeter bezel to mate with the midbass basket.
dave
The Fs of small speakers these days
can be impressive for the size.
All in all dont expect much more than
70 to 100 Hz of bass from a 5"
Reflex will slightly extend that.
But it is just the classic port sound.
I like 5" or smaller speakers
About the size for not needing a waveguide.
And small 3/4" tweeters can be used.
As mentioned this allows very very tight
center to center spacing.
Since many modern tweeters use neo magnets.
the mounting ring isnt large.
So it allows tight mounting.
Ive played with little speakers before for desktop.
For sealed its easy to go crtically damped or max flat Qtc
Just go as big as you can go for .5 to .6 Qtc
usually not more than 6 to 8 liters.
More bass is a simple shelf filter.
Aka turn up the bass knob or add a woofer
Fun project with concrete
should be great for desktop
nearfield listening
can be impressive for the size.
All in all dont expect much more than
70 to 100 Hz of bass from a 5"
Reflex will slightly extend that.
But it is just the classic port sound.
I like 5" or smaller speakers
About the size for not needing a waveguide.
And small 3/4" tweeters can be used.
As mentioned this allows very very tight
center to center spacing.
Since many modern tweeters use neo magnets.
the mounting ring isnt large.
So it allows tight mounting.
Ive played with little speakers before for desktop.
For sealed its easy to go crtically damped or max flat Qtc
Just go as big as you can go for .5 to .6 Qtc
usually not more than 6 to 8 liters.
More bass is a simple shelf filter.
Aka turn up the bass knob or add a woofer
Fun project with concrete
should be great for desktop
nearfield listening
While not so easy with passive components, I would try and reduce that 150hz area. It's peak, makes what's below it seem weak. Not in measurements, but in listening.
I think the Chinese DSP chip boards are over the £20 mark now. However, it could be a nice toy, to reduce that peak, and perhaps lift what is below. To find the balance you are looking for. After which, you may wish to start building again.
Just airing an idea here. When concrete needs to be water proof, some sort of latex additive is used. It allows the particles to better move about each other, so you get a denser concrete. the additive doesn't fill the gaps, it's more of a lubrication. You can buy a readymix aimed at tanking basements, rather than an additive. I'm waffling on about it, as I'm guessing a denser mix would be preferable, and may hold it's corners better. I have also seen concrete polished, which must also have some trick to the casting process.
Quick search "Polished concrete is much like standard concrete with chemical densifiers added to fill the pores to give a dense, durable matrix"
I think the Chinese DSP chip boards are over the £20 mark now. However, it could be a nice toy, to reduce that peak, and perhaps lift what is below. To find the balance you are looking for. After which, you may wish to start building again.
Just airing an idea here. When concrete needs to be water proof, some sort of latex additive is used. It allows the particles to better move about each other, so you get a denser concrete. the additive doesn't fill the gaps, it's more of a lubrication. You can buy a readymix aimed at tanking basements, rather than an additive. I'm waffling on about it, as I'm guessing a denser mix would be preferable, and may hold it's corners better. I have also seen concrete polished, which must also have some trick to the casting process.
Quick search "Polished concrete is much like standard concrete with chemical densifiers added to fill the pores to give a dense, durable matrix"
