Leob.
I remember you 3D printing some panels.
This made me think about down sizing a proplex panel To 3mm and still using the circular flutes.
The size of the panel should be reduced too.
I wonder if the circular flutes are the key element to the good sound of this panel?
Would a thinner lighter panel, still using round flutes sound just as good?
The round flutes make a more sturdy and robust panel than the square flutes.
Steve.
I remember you 3D printing some panels.
This made me think about down sizing a proplex panel To 3mm and still using the circular flutes.
The size of the panel should be reduced too.
I wonder if the circular flutes are the key element to the good sound of this panel?
Would a thinner lighter panel, still using round flutes sound just as good?
The round flutes make a more sturdy and robust panel than the square flutes.
Steve.
Hi Leob
Thanks for your response. To be clear my question was about the simple case when you add a second exciter and leave the volume knob in the same position. If I understood Christian’s answer correctly, he was suggesting that the expected result would be no change in the SPL in that case. Are you suggesting that the expected result would be a 3dB increase? To be absolutely clear I’m not questioning your response. Just trying to be sure I understand it.
My own experience is that the addition of a second exciter doesn’t increase the SPL, or decrease it for that matter as long as the volume knob is left in the same position. I understand that the addition of more exciters should allow more power to be applied to the system but that’s not the case I’m talking about.
Thanks
Eric
Been a heck of a week, but making some progress. Speaker one of four is finished and mounted. I ended up using the threaded hole, and inadequate as that screw is, with soft double-sided tape on the other side it seems to hold together pretty good. I'm attaching the frame to the strips on the wall via pocket holes in the frame.
Attachments
+ @Leob , @spedge
Yes exactly what I suggested. Exciters added in series in a single circuit (branch) give the same SPL for a given voltage as one but a higher power handling and a higher power efficiency. Adding 2 extra exciters in a parallel branch increases the SPL for a given volume. How the coils are wired is a parameter. Have a look to diyAudio : How parallel and series wiringsHow parallel and series wirings affect T/S parameters, the 2 last lines of the table show the SPL@1W and the SPL@2.83V.
Christian
When going from one to two exciters impedance will change, which will change the amount of power the amp supplies in total. So as Christian says, you will get same SPL but lower power consumption with them connected in series.
With four exciters in series-parallel impedance remains the same, so power draw will remain the same, but you will have a 6dB increase in sensitivity.
So with two exciters in series, half the power and same SPL.
With four exciters in series-parallel, same power, +6 dBSPL.
py2pdf
I case I am not alone to have interest in exporting pdf file from a python script under Linux, follow the link above... OK not related to DML but who knows, maybe somebody around looking for that? Next step should be to rewrite the bash file in python for a portability to Windows.
Christian
I case I am not alone to have interest in exporting pdf file from a python script under Linux, follow the link above... OK not related to DML but who knows, maybe somebody around looking for that? Next step should be to rewrite the bash file in python for a portability to Windows.
Christian
There is one big problem mounting the panel up close and flush with the wall.
This will cause heavy cancellation and compression of the sound, this will reduce (remove) the response somewhere below 500hz.
This is easily solved by pulling the far edge out from the wall a few inches or more.
Similar to toeing in a speaker towards you.
I would put stiff hinges on the left supports and do away with the right supports.
You could then move the sides in and out To your preferences.
Believe me the sound will be 100 per cent improved, even with the side wall so close.
Steve.
spedge said:
It will, or it should in theory?
I have the second one up now, that first one may have a construction issue, it sounds fine, but the second one, to the left, is the best I've made so far. The bass is fantastic (compared to my others). I haven't measured with my limited phone app, but when testing the original quick and dirty frame model, it was hanging on the wall and 80hz - 120 hz was pouring off of it. I may get a mic for the purpose later and do more technical testing, and if I find a problem I will try moving it out a little, but that would be just for a test as there isn't room to bring them out. I've considered filling the box with insulation or something to dampen the back waves, I've actually experimented with that prior to the boxes but couldn't hear a difference. well, that stuff would be a second improvement round, I can see my biggest issue for now is getting 4 speakers all of roughly the same quality going.
Hopefully the prices will start to drop over here soon as the postage is very expensive to the UK.
Although I am having some good results from using my 10watt exciters in push pull mode,with no comb filtering, so maybe will use this to drive my low frequency panel from 300Hz or 400Hz to 40Hz (to be decided) .
I am even thinking of finding a way of standing off the exciters a little To minimize the Exciter body problems, this may not work ,but it is worth a try, maybe.
We shall see.
Steve.
There is an EU stockist
https://www.soundimports.eu/en/audio-components/exciters/
When they detect a UK address they deduct their VAT and we pay ours at the boarder. I've not tried this yet. In theory it shouldn't work unless a certain min amount is spent,
On things from the USA I have asked suppliers to use USPS's slow service. Some will some wont. Sad as it's very reliable but can take up to 2 weeks.
I believe any company outside the UK who sells items on line with a total value of under £135 is supposed to register for UK VAT. Some similar figure anyway. No idea if this is working. It is in Germany with some supplier's. They have registered or only take orders of sufficient value. Amazon UK carry some Dayton items including exciters.
Me - very interested in DML's so watching this thread with interest but build wise a woofer comes first.
I asked eurosounds what they do - reply as I posted and no mention of total value. VAT paid here at at the boarder.
Hmmm... Suggests some possibilities to me, PE:
- Has gotten into financial trouble and needs to generate cash,
- Have overstocked on exciters, or
- Intend to release new exciters.
There is also this
The online marketplace must charge and account for VAT at the point of sale, unless the consignment is a business to business sale and the customer has given their UK VAT registration number.
To charge and account for VAT the online marketplace will need to:
but need to read it all again. It was put over in a way that suggests the overseas company had to register for UK VAT,
Consignments valued at £135 or less
The online marketplace must charge and account for VAT at the point of sale, unless the consignment is a business to business sale and the customer has given their UK VAT registration number.
To charge and account for VAT the online marketplace will need to:
- know the precise nature of the goods to find out the correct rate of VAT to charge
- register for VAT — online marketplaces that are already registered for VAT do not need to re-register
- keep records of the goods sold, and make sure they get accurate information to apply the correct VAT treatment to the goods
but need to read it all again. It was put over in a way that suggests the overseas company had to register for UK VAT,Spedge,
I didn't say I can't tell the difference, and I hadn't stumbled across your recording in this sprawling thread. My third panel is done, glue dried overnight and tested it this morning. It sounds better than my second panel (mounted), was leaned against the first panel and I had it in mind that it is a few inches out from the second, and has panel one behind it. The bass is better; or at least, thicker. So I did the test of picking it up and moving it to the wall. It definitely does make a difference, but doesn't make it sound like speaker 2. Then I dismounted speaker 2 and put (unfinished) panel 4 behind it. Speaker 3 still sounds better to me, speaker 2 is a little punchier though and at about the same volume level. I don't think there is anything wrong with it, my guess is that they are two versions of the thruster exciter, the newer version that twists off the base sounds a little better. I'll confirm that by sundown as I have a final panel to build with the newer thruster version.
So yes, distance from the wall definitely made a difference in the test this morning, I will have to do some experimenting with damping once I get other factors under control and see if a little space is worth sacrificing.