Hi,
Beginner speaker builder here looking for some help.
My current goals is to build a decent 2-way speaker for my workshop, one that fits the limited space available. The speaker will be almost against the back wall.
The woofer is a new Dayton Audio RS180P-8.
Enclosure: already built so I could have some woodworking exercise. Ported. Internal net volume is 11,2l. Box is tuned to 49Hz. I did an impedance sweep (DATS v3) and the enclosure is pretty much tuned to this frequency. Leaks should be limited, it all fits nicely and is glued together.
Ports: two 1’’ vents, each 7,5’’ long, on the front.
My first problem now is that low frequency response is terrible. Very little low-end bass sound. Even when hooking up the woofer directly and playing frequencies like 60hz, there is definitely missing something.
I recently also built a much smaller cabinet with a DSA135-8 with a rear bass reflex port, and it has a much better low end sound. So it’s not that I’m unrealistically expecting subwoofer-like bass.
One difference I can think of is that in this build I have two plastic bass-reflex tubes, and the DSA135-8 build has a rectangular MDF port, which is more stiff. The plastic tubes in this build aren’t that rigid, I don’t know if that’s important.
So my hope now is that there is a major design flaw with what I built. Thanks for any hints that put me on the right path again. I'm a bit stuck here.
Vincent
Beginner speaker builder here looking for some help.
My current goals is to build a decent 2-way speaker for my workshop, one that fits the limited space available. The speaker will be almost against the back wall.
The woofer is a new Dayton Audio RS180P-8.
Enclosure: already built so I could have some woodworking exercise. Ported. Internal net volume is 11,2l. Box is tuned to 49Hz. I did an impedance sweep (DATS v3) and the enclosure is pretty much tuned to this frequency. Leaks should be limited, it all fits nicely and is glued together.
Ports: two 1’’ vents, each 7,5’’ long, on the front.
My first problem now is that low frequency response is terrible. Very little low-end bass sound. Even when hooking up the woofer directly and playing frequencies like 60hz, there is definitely missing something.
I recently also built a much smaller cabinet with a DSA135-8 with a rear bass reflex port, and it has a much better low end sound. So it’s not that I’m unrealistically expecting subwoofer-like bass.
One difference I can think of is that in this build I have two plastic bass-reflex tubes, and the DSA135-8 build has a rectangular MDF port, which is more stiff. The plastic tubes in this build aren’t that rigid, I don’t know if that’s important.
So my hope now is that there is a major design flaw with what I built. Thanks for any hints that put me on the right path again. I'm a bit stuck here.
Vincent
Simulate the woofer in Winisd (freeware) with the parameters you got from DATS V3.
And measure the frequency you have now in Rew (freeware). Cheapest option is umik-1 microphone. If the woofer just can’t produce bass, and it starts being sloppy too soon because of the low tune, you can try a higher tune and get a little snappier midbass.
It does not look like a subwoofer, so just get a subwoofer for it. Trying to get the last bass out of that little woofer will probably not sound as good as having a dedicated subwoofer.
60Hz is pretty good, I like to add a subwoofer at 70Hz. Although right now I use a 10 inch driver for bass from 25-250Hz. It has a lighter cone and I think it is more musical than a home theater subwoofer.
And measure the frequency you have now in Rew (freeware). Cheapest option is umik-1 microphone. If the woofer just can’t produce bass, and it starts being sloppy too soon because of the low tune, you can try a higher tune and get a little snappier midbass.
It does not look like a subwoofer, so just get a subwoofer for it. Trying to get the last bass out of that little woofer will probably not sound as good as having a dedicated subwoofer.
60Hz is pretty good, I like to add a subwoofer at 70Hz. Although right now I use a 10 inch driver for bass from 25-250Hz. It has a lighter cone and I think it is more musical than a home theater subwoofer.
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The crossover is actually another problem but one I didn't dare to mention in the original thread
I would like to fix the low frequency problem first.The bass is the same when I connect the woofer directly to the amp or when I use my low pass filter. When I connect it directly I turn down the high frequences on the source.
So the crossover is not the problem unfortunately.
The sound is pretty much the same, maybe a bit more LF with no socks, but it's minimal.
The vents are not obstructed inside, and have at least 7cm breathing room in the back
For fun I plugged the drivers parameters into an online calculator. There seems to be conflicting data about the VAS between the Dayton Audio site and the parts-express site. I used the PE number of .78 cu ft or 22.08l . for 11l cabinet the port length should be 6.75cm for 2 X 2,54 cm ports.. The ports you are using are 19.05 cm long and may be the problem. Please do some research on your own before cutting anything, but i have noticed that smaller diameter ports are shorter than larger diameter ports for the boxes i have built. Good luck
Sorry it seems I made a mistake in my initial post, I'm a metric system person and goofed up the conversion. So in reality I'm using 35mm ports. 19cm long
What is the conflicting data? Parts-express says 0.78cubic feet,the spec sheet says 22l, which seems to be correct.
A 'bad' crossover can allow the mids and highs to be too loud, which is similar to having no bass.The crossover is actually another problem but one I didn't dare to mention in the original thread
I also get ~50 Hz tuning with those ports.
Does the woofer cone move visibly by several mm when driven at medium to loud volumes? What amplifier are you using?
I double checked and the ports were actually 21cm long . So I was a bit euphoric, thinking "this is it", and I shortened the ports to 15cm, what should give me a tuning of about 53Hz. This is what WinISD suggests and well, that should be ok or at least close to something that works. Now in reality it doesn't make alot of difference.
I'm using an Onkyo TX535 amp, which can get excellent results from some old Infinity Reference MkII 5.1, and also from my first project with a DA135-8 woofer. It has 6l internal volume with a rectangular port. And it has a very clear advantage in the low frequence area. You can feel the bass. It's half the size of the new speaker.
The RS180P-8 does move, but only at high volumes.
Maybe the DA135-8 is just a fantastic driver and I'm expecting too much from the RS180P-8?
Note: currently I'm using a Low Pass Filter only, and the tweeter is not connected. I already tried hooking up the woofer directly, and on the music source (my computer) I use an EQ to do the low pass filter. Identical results. The physical LPF is not causing this problem.
. So I was a bit euphoric, thinking "this is it", and I shortened the ports to 15cm, what should give me a tuning of about 53Hz. This is what WinISD suggests and well, that should be ok or at least close to something that works. Now in reality it doesn't make alot of difference.I'm using an Onkyo TX535 amp, which can get excellent results from some old Infinity Reference MkII 5.1, and also from my first project with a DA135-8 woofer. It has 6l internal volume with a rectangular port. And it has a very clear advantage in the low frequence area. You can feel the bass. It's half the size of the new speaker.
The RS180P-8 does move, but only at high volumes.
Maybe the DA135-8 is just a fantastic driver and I'm expecting too much from the RS180P-8?
Note: currently I'm using a Low Pass Filter only, and the tweeter is not connected. I already tried hooking up the woofer directly, and on the music source (my computer) I use an EQ to do the low pass filter. Identical results. The physical LPF is not causing this problem.
Do an impedance measurement. Very easy. You don't even need a perfectly exact calibrated reverence resistor, as you only look for the peaks and low's of the curve, not absolute values. This tells you how far off you are with your tuning.
So a few wires, a resistor and some free program will take the guessing out of your build.
So a few wires, a resistor and some free program will take the guessing out of your build.
Hmm, based on published specs a max flat BR is ~12.51 L net, ~54 Hz Fb, so a bit small for max flat LF, though up against a wall will boost the lows up to +3 dB, but you'll need to tune up around 1.56x Fs = ~71.44 Hz to get the ~ prosound mid bass 'bump' you apparently want to fill in the wall gain.
WinISD has a setting that computes the size for two port tubes. Make sure you are using that setting when doing the calculations. If you just use two of the ports that were computed as a single tube, the result will be off. That is an exceptionally good 7" driver and it has distortion nearly as low as the very much more expensive Seas and Scanspeak drivers. I have only used it as a lower midrange paired with a 12" woofer. It operates as a perfect piston up to around 800Hz.
That's a home theatre amp. Could you double check that the relevant speaker channels are set to 'large'? If set to 'small', it will apply a high pass filter at 80 Hz.
I checked the Onkyo, it is set correctly.
Thanks all for your comments. I configured everything correct in WinISD the first time, aimed for a flat response, but I think I was just aiming for a sound that is not what I want. In reality I guess I indeed want that extra "umph" in the lower frequencies. It's a workshop speaker and I will be wearing ear protection from time to time
WinISD: initial Fb was 52 Hz (light blue) with the double 3,5cm ports.
I plugged the vents, made a new single port on the back, aiming for Fb 73Hz. (red)
DATS v3 measurements for the enclosure with the new port. I'm off by a hefty 5Hz but that's probably also because I'm hacking the enclosure, socks in the old vents etc.
It now sounds more the way I like it.
I guess I won't be getting any audiophile awards for this tuning
Thanks all for your comments. I configured everything correct in WinISD the first time, aimed for a flat response, but I think I was just aiming for a sound that is not what I want. In reality I guess I indeed want that extra "umph" in the lower frequencies. It's a workshop speaker and I will be wearing ear protection from time to time
WinISD: initial Fb was 52 Hz (light blue) with the double 3,5cm ports.
I plugged the vents, made a new single port on the back, aiming for Fb 73Hz. (red)
DATS v3 measurements for the enclosure with the new port. I'm off by a hefty 5Hz but that's probably also because I'm hacking the enclosure, socks in the old vents etc.
It now sounds more the way I like it.
I guess I won't be getting any audiophile awards for this tuning
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