Hello David, thank you for taking the time
Welll spotted, I missed setting the units next the input box from mm to um
The driver is a Chinese OEM and there are now 4 brands that I have come across that seem to have a variation on the same general package. Just the stamping on the frames, some magnet differences, colours and such. I have been told before purchase that I will need to take my own measurements for it to be any use but can use the specs from the Elite ZR6 to get in the ballpark. This is from a colleague that was a renowned installer and just an experiment to see if I can get his results. His use was car based though and in the SQ circuits. Something he was considering getting a few of as his house brand. This is from a while back though
I really don't have much use for this 20hz box. Just interested to see what the hype was all about and just to be able to say hey this box can do 20hz. I have simmed my fav bass loudspeaker for reverse engineering the tuning and worked out that it's 43hz. The driver will prolly die in testing, I have allowed for that and looking at getting a second unit if it nails the 43hz box well first. I am also looking at getting the 6.5" from DD Audio, CT Sounds and have already ordered the Elite ZR6.4D too. Will run the OEM against the DS18 first
As already noted, this is just to see if it can confirm some boasts, and attempts to steer me away from JLAudio drivers. At the start of the thread most folks called out attention to the fact that the box/port aspect is not too great and potential issues. I am unfamiliar with those issues so thought it will be a great opportunity to learn to hear and measure both good and bad. I picked up a Bheringer calibrated mic and all sorts of things to build and measure these types of things
At the moment, I am failing to get my head around this. Is the peak around 100-200hz? I see two humpy areas. GM posted a resource about pipe resonances. Reading around that, I noticed some links to applications to musical instruments. Something I was asking Gnobuddy a long time ago was if I can enhance and effect the port on a bass amp to play along and add more dimension to a bassline. I am now also thinking if I could trial and error my way along using this box as a start and see if there are mods that will effect the bass nicely. I have a Roland JDXI synth keyboard that has an input that can track a bass guitar and play along with one of its 4 engines with all sorts of oscillations and wave shapes that only a synth can do. Sounds like some fun messings around potential. Please dont take this all too seriously as free time to tinker like this is evaporating
You are prolly right about this. Just curious about some input from a friend who tried once to teach me what specs to look at for very low box volumes and recommended drivers. The CT option has FS 45hz and VAS 7L for the 8" version. And lowest FS out of all the drivers that seem to be wearing a common basket and cone/surround
Any recommendations for drivers under 8" that can do a solid 20hz?
Thanks again for your time man, very much appreciated. I hope you get the educational and recreational thrust of this thing. I prolly will not actually use it
Thanks and regards
Randy
Noted. I'll be more careful about checking the units and decimal spots from manual specs to application input box labelling. Why can't they keep it consistent? Is there any real reasons for one program to work in cm, the other to have cm on this box, mm on the next and so on?
Actually, we do want an HT system in the houseboat layout that we are testing in the new side room where we just built a new kitchen and dining area. We live in a "tiny home" and also are working on a tiny home based on a 6m x 3m houseboat that we have already prepared very high performance hulls for
I am looking for the tiniest 16hz system that we can fit in, any suggestions? Space is a major issue!
I am looking for the tiniest 16hz system that we can fit in, any suggestions? Space is a major issue!
Bob Carver's Sunfire "True Subwoofer" at around one cubic foot with 16Hz response produced more low clean bass for it's size than anything I have heard.
It's combination of processing, amp, driver and passive radiator work amazingly well.
Probably cost more to DIY than to buy, but for maximum VLF output for enclosed volume, the passive radiator approach is hard to beat.
It's combination of processing, amp, driver and passive radiator work amazingly well.
Probably cost more to DIY than to buy, but for maximum VLF output for enclosed volume, the passive radiator approach is hard to beat.
I was in high school when Australian Hi-fi magazine featured it. I took my Greensleeves sampler CDs with Robbie Shakespeare heavy on the basslines to all the Sydney Hi-fi shops to audition subs when I could afford to some years later, and there was nothing quite like the Sunfire at all. The closed I came to having the huge amounts of bass in my room was a JLAudio 13W7 and a 1kw PA amp some more years later. That was the first driver of its kind to make its way here
You mentioned Sunfire and someone on my 40hz thread mentioned under seat subs. This has got me thinking and talking to a couple of reps. This is for a usable box for change 😀
Now, for a keeper HT soundbar for the houseboat. This will be on a shelf in front of the parent's bed. The space limits remain, and an even more ambitious target of a usable target of 16hz. I have a JLAudio 1000/1 from my old car in storage at my folks for the houseboat, as well as 500wrms per channel modules from Erica.C that I can run off the 240v system on the boat
Ideas?
I am inclined to explore a wall hanging cab over the shelf (maybe instead of) with 1 active driver and two PR drivers with the satellites wall mounted also on each side of the sub
You mentioned Sunfire and someone on my 40hz thread mentioned under seat subs. This has got me thinking and talking to a couple of reps. This is for a usable box for change 😀
Now, for a keeper HT soundbar for the houseboat. This will be on a shelf in front of the parent's bed. The space limits remain, and an even more ambitious target of a usable target of 16hz. I have a JLAudio 1000/1 from my old car in storage at my folks for the houseboat, as well as 500wrms per channel modules from Erica.C that I can run off the 240v system on the boat
Ideas?
I am inclined to explore a wall hanging cab over the shelf (maybe instead of) with 1 active driver and two PR drivers with the satellites wall mounted also on each side of the sub
OK, thanks for the parameters.
The manufacturer hasn’t done you any favours to be fair, one is presented in a non standard way and some need a little knowledge to understand.
First up, Le given as 461.9mmH is stupid, they should have just said 0.46mH instead of stacking two “milli” prefixes.
Next up, being a dual coil woofer, there are a couple of ways of connecting it, namely series and parallel. They’ve given you BL for parallel, but you’re wanting to use it in series, so we need to double the figure for BL we use. That, incidentally, puts it closer in line with the value you had in your Hornresp record. ASSUMING Le was also for parallel, we’ll also need to double that for series wiring.
Lastly, Mms, Cms & Fs don’t quite tally up exactly. If Mms & Cms are exact, Fs should be a bit higher than 70, more like 77Hz. If Fs & Mms are exact, then Cms should be higher at 116um/n, and if Fs & Cms are exact then Mms should be higher at 53.8g. These are only ~10% out from the published values, so allowing for production tolerances and room acoustics affecting the final response it’s probably not critical but it’s certainly a bit annoying.
So, here are the parameters I’m going to use for the time being:
Note that most of the top section are in blue, meaning I’ve input the more fundamental, underlying electrical & mechanical characteristics in the middle block of the input screen 1st and let WinISD calculate as many as possible of the TSPs itself.
Now, on to the modelling.
First up, the resonant peak I was talking about is the one right at Fb. If you go to your filters tab and untick the parametric EQ, you’ll see the underlying response, and you’ll be able to see that 22.5Hz is nearly 5dB louder than 30Hz. That’s the kind of peak you really want to avoid.
Next, considering the overall response. I wouldn't even attempt to create a modelled response that has peaks in the bass. That’s partly for the resonance reasons already mentioned but also because of room gain. That’s a topic you can read up on yourself but basically, real world spaces that are not too big tend to add some free gain for us at very low frequencies. The exact amount depends on room sizes and construction, but if we assume we might get a bit, then adding that on to any existing peak in the modelled response can end up sounding even worse if it makes the peak too prominent. Therefore, a better target response is one the drops off more gradually. With the updated ZR6.4 parameters, the blue curve here is one I’d consider a (slight) improvement:
The EQ has changed slightly (wider and higher boost) and the tuning frequency has dropped to 22.5Hz to keep excursion from exceeding Xmax above 20Hz. The net power stays around 600W instead of the 6000W you would have needed with the older versions of the parameters, and it gets a bit louder. There's still a bit of a peak at tuning, but it's a little better than before.
There is a down side to getting louder however, that is that the port needs made (a lot!) bigger to avoid the airspeed getting high enough that it risks becoming turbulent, which adds unwanted noise (chuffing) and reduces the benefit of the port in the first place. Note however that your original port would be well into that territory anyway (see the “Rear Port – Air Velocity” graph in WinISD).
If you don’t like the look of the broad hump centred around 100Hz, another PEQ would take care of that – 110Hz, Q 0.8 and -2dB should be enough.
You asked if I knew any more suitable driver – in short, no. I wouldn’t even try getting 20-ish Hz response out of such a small box & driver, due to all the issues you’re discovering in this process.
Just to demonstrate what I’d consider a bit more sensible, the red curve here is a Dayton DCS205-4 (8”) in 35l net, tuned to 22Hz, with one PEQ of +4dB @ 30Hz, Q = 1. The benefits are a smoother response that relies much less on a peaky port resonance and will likely sound better, especially with room gain factored in; a shorter vent (thus easier to construct) and it takes ~seven times less power than the ZR6.4 to get this level. The downside (for you at the moment at least) is that it is over three times bigger, but hopefully it shows how much more is possible once you free yourself from extreme size constraints. Note also the Dayton is a pretty cheap driver, there are many better out there if more performance is needed. Both project files are in the zip if you want to have a play yourself.
Cheers,
David.
The manufacturer hasn’t done you any favours to be fair, one is presented in a non standard way and some need a little knowledge to understand.
First up, Le given as 461.9mmH is stupid, they should have just said 0.46mH instead of stacking two “milli” prefixes.
Next up, being a dual coil woofer, there are a couple of ways of connecting it, namely series and parallel. They’ve given you BL for parallel, but you’re wanting to use it in series, so we need to double the figure for BL we use. That, incidentally, puts it closer in line with the value you had in your Hornresp record. ASSUMING Le was also for parallel, we’ll also need to double that for series wiring.
Lastly, Mms, Cms & Fs don’t quite tally up exactly. If Mms & Cms are exact, Fs should be a bit higher than 70, more like 77Hz. If Fs & Mms are exact, then Cms should be higher at 116um/n, and if Fs & Cms are exact then Mms should be higher at 53.8g. These are only ~10% out from the published values, so allowing for production tolerances and room acoustics affecting the final response it’s probably not critical but it’s certainly a bit annoying.
So, here are the parameters I’m going to use for the time being:
Note that most of the top section are in blue, meaning I’ve input the more fundamental, underlying electrical & mechanical characteristics in the middle block of the input screen 1st and let WinISD calculate as many as possible of the TSPs itself.
Now, on to the modelling.
First up, the resonant peak I was talking about is the one right at Fb. If you go to your filters tab and untick the parametric EQ, you’ll see the underlying response, and you’ll be able to see that 22.5Hz is nearly 5dB louder than 30Hz. That’s the kind of peak you really want to avoid.
Next, considering the overall response. I wouldn't even attempt to create a modelled response that has peaks in the bass. That’s partly for the resonance reasons already mentioned but also because of room gain. That’s a topic you can read up on yourself but basically, real world spaces that are not too big tend to add some free gain for us at very low frequencies. The exact amount depends on room sizes and construction, but if we assume we might get a bit, then adding that on to any existing peak in the modelled response can end up sounding even worse if it makes the peak too prominent. Therefore, a better target response is one the drops off more gradually. With the updated ZR6.4 parameters, the blue curve here is one I’d consider a (slight) improvement:
The EQ has changed slightly (wider and higher boost) and the tuning frequency has dropped to 22.5Hz to keep excursion from exceeding Xmax above 20Hz. The net power stays around 600W instead of the 6000W you would have needed with the older versions of the parameters, and it gets a bit louder. There's still a bit of a peak at tuning, but it's a little better than before.
There is a down side to getting louder however, that is that the port needs made (a lot!) bigger to avoid the airspeed getting high enough that it risks becoming turbulent, which adds unwanted noise (chuffing) and reduces the benefit of the port in the first place. Note however that your original port would be well into that territory anyway (see the “Rear Port – Air Velocity” graph in WinISD).
If you don’t like the look of the broad hump centred around 100Hz, another PEQ would take care of that – 110Hz, Q 0.8 and -2dB should be enough.
You asked if I knew any more suitable driver – in short, no. I wouldn’t even try getting 20-ish Hz response out of such a small box & driver, due to all the issues you’re discovering in this process.
Just to demonstrate what I’d consider a bit more sensible, the red curve here is a Dayton DCS205-4 (8”) in 35l net, tuned to 22Hz, with one PEQ of +4dB @ 30Hz, Q = 1. The benefits are a smoother response that relies much less on a peaky port resonance and will likely sound better, especially with room gain factored in; a shorter vent (thus easier to construct) and it takes ~seven times less power than the ZR6.4 to get this level. The downside (for you at the moment at least) is that it is over three times bigger, but hopefully it shows how much more is possible once you free yourself from extreme size constraints. Note also the Dayton is a pretty cheap driver, there are many better out there if more performance is needed. Both project files are in the zip if you want to have a play yourself.
Cheers,
David.
David, many thanks again. I'll take my time and go over what you explained a few times. Some quick ones. Re the voice coils. They won't be connected together, and I didn't really know how to enter that
As you mentioned the Dayton, with the current shipping rate of about $160 AUD for that, I would be more inclined to spend up on an even nicer driver. The space allocation actually calculates to about 40L, either on the shelf or the wall just above it. It just needs to be max 180mm in the smallest reach and 900mm in the longest
I am trying to sim the ZXI10.4D in a 35L with 20hz. Looks better than the 6.5" drivers. Now that we want HT on the houseboat, I wouldn't mind if it hit a bit harder than the smaller speakers. I am also going to try a sim with two PR drivers once I get a handle on them. Looking at SBA ones that I can get for about $160. There could be a flat sub worth a try too. Maybe even pressed into PR duty. Looking at some now
As you mentioned the Dayton, with the current shipping rate of about $160 AUD for that, I would be more inclined to spend up on an even nicer driver. The space allocation actually calculates to about 40L, either on the shelf or the wall just above it. It just needs to be max 180mm in the smallest reach and 900mm in the longest
I am trying to sim the ZXI10.4D in a 35L with 20hz. Looks better than the 6.5" drivers. Now that we want HT on the houseboat, I wouldn't mind if it hit a bit harder than the smaller speakers. I am also going to try a sim with two PR drivers once I get a handle on them. Looking at SBA ones that I can get for about $160. There could be a flat sub worth a try too. Maybe even pressed into PR duty. Looking at some now
Btw...I tried to work on a couple of larger drivers today. File attached. Hopefully this time I can show that I have learned something and have better results. I like the flatness of the pancake speaker, but still can't really tell if they are too much apart. I can do a flat box with 100mm across, the smallest reach with that driver. I have left the 5L spare volume over the shelf for adding to the net volume with either port or PR and other electronics in the box
This brand seems to offer drivers with some of the lowest box volumes around. I have a few drivers already at home and one of the ZR6 on its way from Big Jeff as well as the Chinese one from my friend
I think ruled out the Dayton Ulimax a long time a go. Have to check out their and earthquake pancakes next
This brand seems to offer drivers with some of the lowest box volumes around. I have a few drivers already at home and one of the ZR6 on its way from Big Jeff as well as the Chinese one from my friend
I think ruled out the Dayton Ulimax a long time a go. Have to check out their and earthquake pancakes next
You will need to connect the voice coils, unless you're driving it from a 2 channel amp that is itself being fed a mono signal. Otherwise, you'd only be getting half the power rating of the driver and the parameters would change again. Connecting them in series isn't difficult - connect the + wire from the amp to the + terminal of one coil, connect the - terminal of that 1st coil to the + terminal of the second coil with a short length of speaker cable, and return from the - terminal of the second coil to the - terminal of the amp. The parameters I've used (Re 6.8 and BL 13) already account for them being in series.
$160 shipping on a $169 driver does sound steep, is that from abroad or within Aus?
$160 shipping on a $169 driver does sound steep, is that from abroad or within Aus?
Using dedicated modules per coil. have selection from 150wrms channel to 700wrms on hand. These have integrated PSU. So how are two active coils then entered into Winisd and HR. I made an assumption for two bridged channels on the 350wx2 amp and put the coils in series for an easy load. Something about he PSU outputs equal power in 4 or 8R
Most drivers discussed on the forum are not available AU. I asked FedEx yesterday for a quote to pick up a 30x30x20cm box @5kg from Florida for me and was quoted $720 US for standard! There was a time when I could get a 2.5m long parcel from florida for only $100!
The SB PR is available locally, similar size and weight item was $160 from Parts Express
The ZR6 is coming via ship for $80 AU
The ZXI10 will be steep but will eat less junk for a while 😀
Most drivers discussed on the forum are not available AU. I asked FedEx yesterday for a quote to pick up a 30x30x20cm box @5kg from Florida for me and was quoted $720 US for standard! There was a time when I could get a 2.5m long parcel from florida for only $100!
The SB PR is available locally, similar size and weight item was $160 from Parts Express
The ZR6 is coming via ship for $80 AU
The ZXI10 will be steep but will eat less junk for a while 😀
Here is what I think I should have learnt from this thread. Please assist further by pulling out the red pen. Much appreciated guys
1 - Any ported box tuned low and made to fit the allocated space is going to keep asking the BR or TL question
Action, build the 6.5" based "thing" to answer and learn from
2 - Driver is low in cone area and high Fs
Action, selected a larger driver with lower FS of 29hz made to work with small volumes, the ZXI10.4D
https://ds18.com/cdn/shop/files/ZXI...0-9a88-8fe34d12869a.pdf?v=9591678357036594353
Bar20s in the attached zip is the ZXI10.4D in 35L max volume allowed. Simmed as a ported, but I expect similar output with the right PR setup. Which is the answer to point 1 as that is a dimension problem with allocated space
This is a quick sketch of the active driver in the middle and a PR to each side. The box is 320mm tall, 180mm deep and 900mm wide
I hope to have achieved a usable result in the sim hoping for the following and hope for correction if I am making a mistake in thinking this is a good result inside the 5m x 3m x 2.4m tall open plan cabin. 1kwrms amp:
A good frequency response without eq
Potential gain from wall mounting to hopefully increase output to 16hz F3 or better in the room
Compact size that will not take up floor space or protrude in the room space much more than the wall mounted TV
Solid output to tun up the volume when moored away from others
1 - Any ported box tuned low and made to fit the allocated space is going to keep asking the BR or TL question
Action, build the 6.5" based "thing" to answer and learn from
2 - Driver is low in cone area and high Fs
Action, selected a larger driver with lower FS of 29hz made to work with small volumes, the ZXI10.4D
https://ds18.com/cdn/shop/files/ZXI...0-9a88-8fe34d12869a.pdf?v=9591678357036594353
Bar20s in the attached zip is the ZXI10.4D in 35L max volume allowed. Simmed as a ported, but I expect similar output with the right PR setup. Which is the answer to point 1 as that is a dimension problem with allocated space
This is a quick sketch of the active driver in the middle and a PR to each side. The box is 320mm tall, 180mm deep and 900mm wide
I hope to have achieved a usable result in the sim hoping for the following and hope for correction if I am making a mistake in thinking this is a good result inside the 5m x 3m x 2.4m tall open plan cabin. 1kwrms amp:
A good frequency response without eq
Potential gain from wall mounting to hopefully increase output to 16hz F3 or better in the room
Compact size that will not take up floor space or protrude in the room space much more than the wall mounted TV
Solid output to tun up the volume when moored away from others
Hi,
Acoustically, that looks a lot better yes.
Bear in mind that if you are going to go with PRs instead of the vent, you can model it in WinISD - when you start a new project, the next part of the popup after selecting your driver has a dropdown menu to select that. As PR's have their own parameters, you may not get an exact match for the frequency response but you should be able to get close.
Good luck,
David.
Acoustically, that looks a lot better yes.
Bear in mind that if you are going to go with PRs instead of the vent, you can model it in WinISD - when you start a new project, the next part of the popup after selecting your driver has a dropdown menu to select that. As PR's have their own parameters, you may not get an exact match for the frequency response but you should be able to get close.
Good luck,
David.
In case you drive both amps with the same signal it is just the same as driving the voice coils in parallel with a very stable amp. The virtual "very stable amp" in reality is two separate amps, but the speaker simulator won't care.
The resulting impedance for paralleled coils will double in reality for each amp.
Thanks man. Am I correctly hoping for some boost from the wall down to a usable 16hz?
Eagerly waiting for the table saw to arrive 😀
Thanks man. So, when I try to re-enter the zR6, Re should be set to 3.4 as the driver is rated Re 3.4 + 3.4, select option for 2 VCs and select parallel?
