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Dameo182
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10/10/2020 8:58 pm  

I mentioned in an earlier thread that i was planning this, ive bought an av reciever, 165watts to 7 channels, 1 channel driven. The speakers i want to use for this need to be around 30- 50watts rms i think, someone correct me if im wrong, but i also want the speakers to be quite small. I just like small speakers with big sound. And speaking of the sound, i want to be able to have the surround speakers play down to around 50hz. So in total i need a sub, two fronts, one centre and at least two surrounds, eventually atmos speakers too once ive learned how to design and make those. Would the rs100 drivers be a good choice for all of the above apart from the sub? The sub im thinking i could use the tang band w5. Or are there better options i could use? 

 


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TVOR-Ceasar
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13/10/2020 3:48 pm  

-Charlie


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Dameo182
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13/10/2020 4:07 pm  

@tvor-ceasar

 

Thankyou, i pm'd you the link to the reciever i bought 


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Dameo182
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13/10/2020 5:23 pm  

Also, i took this picture from the instruction manual if that gives more specific details, it only makes me worried that id be way overpowering single 30 watt satalite speakers if i went with a 30 watt 4ohm midrange or full range and added a 4ohm tweeter to make it an 8 ohm load, but honestly im so unsure about how much power these speakers will get, especailly the front left and right ones on the stereo setting that im hesitant to design anything yet as i could be way off with my thinking. Anyway im sure you can make more sense of the specs than i can lol

20201013 184240

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TVOR-Ceasar
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13/10/2020 10:14 pm  

Looks like the Sony STR-DN 1080. And looking at the photo,you'd probably want to go with something a bit more sturdy. And it would be judicious to go with the 8 ohm versions of whatever you decide to use, just to keep it safe for everything,, that is, if you  plan on running it wide open. Now, if you don't plan on really pushing it past about 1/3 - 1/2 power, you could probably go with the PC83-8 for all the drivers. At least for now.

-Charlie


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Dameo182
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14/10/2020 4:26 am  

Thanks, im just kinda skeptical about the 165 watts to the channels on the surround setting, ill send you a link to the video of a review on this avr when i get home from work, the guy says he thinks its around 50 watts per speaker, but then because ive seen other things claiming thats wrong im just massively confused by what i need in regards to the power handling, id like to get away with using the pc83 if i can though. 

A quick question about tge ohms part of this is, if i put two 4ohms in the surrounds, that gives me the 8 ohms, does that mean the 165 watts, if true, drops to around 130, and if i do that does the wattage handling of the two drivers become 60 watts rms or does that drop too back diwn to around 40 watts for both speakers? Sorry if that doesnt make much sense, im trying to type quickly as im on break at work


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TVOR-Ceasar
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14/10/2020 10:08 am  
Posted by: @dameo182

Thanks, im just kinda skeptical about the 165 watts to the channels on the surround setting, ill send you a link to the video of a review on this avr when i get home from work, the guy says he thinks its around 50 watts per speaker, but then because ive seen other things claiming thats wrong im just massively confused by what i need in regards to the power handling, id like to get away with using the pc83 if i can though. 

A quick question about tge ohms part of this is, if i put two 4ohms in the surrounds, that gives me the 8 ohms, does that mean the 165 watts, if true, drops to around 130, and if i do that does the wattage handling of the two drivers become 60 watts rms or does that drop too back diwn to around 40 watts for both speakers? Sorry if that doesnt make much sense, im trying to type quickly as im on break at work

That would be much better, two of the 4 ohm units in series to make an equivalent 8 ohm speaker. 

When you combine multiple speakers to make 1 equivalent unit, regardless of series or parallel, you are just adding the power ratings together. Reason being that you are pushing just 1 signal through that particular combination's number of speakers, effectively dividing it up at the beginning and then recombining it at the end so that it only sees the equivalent impedance. Lots of theory that could be thrown out there, but for resistance and impedance, that's pretty much it in a nutshell.

So ultimately, you'd get 60W-120W ratings, double the Vas and then go from there. If you are using WinISD, it'll do all that for you. Another bonus is that for the same amount of power, that combo would only use 1/2 the Xmax that a single driver would, which means you've got more headroom.

Plus, once you hit 10 units, the price per unit drops!

 

As to the true power of the amps, you'd have to feed a 1K signal into the amp, into a non-inductive load (power resistor) of the appropriate value (with all channels driven), look at it with a O-Scope to see when distortion starts, then measure the RMS value (scopes usually do this for you), square that value and then divide it by the load. I mentioned JohnAudioTech on YouTube as a guy I've been watching even before that was his channel's name. He does this quite often.

Reason I said that If you were not going to use that much power from the amp is because most use a Logarithmic Volume control that slowly ramps up and then really puts the juice to it nearer the end, so that most times, when the volume seems loud or at the normal level you'd use, it really runs between 2-10 or 20 watts. Lower levels, like background type levels where you are able to hold conversations with others over the content are actually well under 1 watt, say 125-250 milliWatts. I think that tidbit came from Nelson Pass. He's a cool guy to listen to, too - Check out his interviews on The Audiophiliac Daily Show with Steve Guttenberg on YouTube.

-Charlie


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Dameo182
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14/10/2020 12:56 pm  

@tvor-ceasar

 

As usual a very detailed reply, thankyou for that, so yeah i think ill go for the two drivers, basically ill make 3 identical speaker units, one for the centre and the other two for the surrounds, i dont how to work out what adding a tweeter to the speakers will do to the ohms though. If i added say a 4ohm tweeter to the two 4ohm pc83's, how will that effect the ohms of the completed speaker? Or does that depend on how its wired? 

Given that i have to keep the volume down to avoid upsetting the nieghbours i definately wont be maxing out the avr, so i think you might have helped me finally get to a decision on how to get started on this. I now just wanna check that making two of the dinas speakers for the left and right is a good match? Replacing the rs100 drivers for the pc83 just so they visually look part of the set. 


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TVOR-Ceasar
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14/10/2020 7:27 pm  

**(For those following along, here's the Manuals page of the AVR we are talking about)**

If you were to add a tweeter, you could do a MTM style speaker. Again, the 2 mid-woofers/full range drivers would be wired in series to get 8 ohm equivalent. For the tweeter, it is usually good form to follow along with a similar impedance, so you would be looking for a single 8 ohm tweeter. There are many to choose from.

Your question about what using a tweeter with the other speakers is a good one. The answer is that the crossover takes care of maintaining the correct impedance by dividing up the frequencies and directing them to the appropriate drivers.

The DINAS, I'd refer that to Nick since they are his design. I can say that you'd have to do some recalculations for box size, crossover, and maybe more. It would be a different voicing, that's for sure.

One thing you could do is use the Sub Outs one your AVR (they look like line level) and build either a pair of Mini Earthquakes or a pair of Voxels. Or design one on your own / with help. Power them with a decent Class D. It'd work out well, I bet. That way, you could run all your surround channels with the exact same voicing.

-Charlie


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Dameo182
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15/10/2020 8:00 am  

@tvor-ceasar

 

Ok great, now i think i know what im doing about the centre and the surrounds, ill do the mtm style as you mentioned since i was unsure about the finished ohms, due to my reciever only going as low as 6ohms, but thanks for clearing that up for me. 

 

I was goung to ask nick about tgat, but given hes feeling under tge weatger right niw i decided to try and wing it and learn what i could about them from his video, im a bit worried i might be overdoing the amount of subs if i went with dinas design, id then have one in each left and right aswell as the main sub, so im considering using the same design mtm speakers for everything but then it might be too lacking in bass on the stereo setup lol i hate overthinking things so much. What would you think to be the best choice of the two ideas?

I would probably need sone help designing a sub to be honest, since ive bever done one before, what benifit do you get from 2 subs over just the one? 


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Dameo182
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15/10/2020 5:35 pm  

Im trying to design the crossover using xsim, but no matter what i try it will only let me upload one of the 4 frd files when i click the driver to tune it, why is it doing that? Surely it needs all 4 of them to give me the correct response? 


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TVOR-Ceasar
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16/10/2020 12:42 am  

I was looking at the AVR's data sheet, going over what mode does what. I see that when it is in 2 channel mode (regular stereo), the sub outs are not used. I see now why you were thinking of going with a slightly different L & R speaker style.  

Which got me to thinking...

Some of the other posts within a month or so highlight the modular system with the bass unit integrated, yet detachable. Since one of the goals of an AV system is to have similarly voice matched speakers throughout, you could do 5 of the same MTM for LCR RR LR, and if you wanted just a single driver for the 2 Height channels. Voicing is pretty well matched. (From what I'm hearing about the height channels, they don't get that much use, and the power they'd use is fairly low, so it'd probably be okay to use the same driver). 

Then, for the AV subs, you would do the line in powered units. 

Pretty standard so far.

Now, for when you want music, you'd want a bit more substance from L+R. You could use a ~5-1/4" to 6-1/2" woofer (not a sub-woofer, you want it to be musical) built into a box that could wrap around behind the L+R speakers to enhance their low end, bolstering from about 100-120Hz down to around 40+-Hz. These would be low-passed in the crossover, but you could put a switch in line to turn them off for movies. Or, you may find they enhance the L+R enough to keep them always on.

Anyway, that's a thought I had to try to address your concern when in stereo mode. 

Back to what's on the drawing board. You've settled on the PC83-4 wired in series and a tweeter. What 8 ohm tweeter are you looking at? 

I ran a quickie and it looks like a .38 CuFt box (allowing for some extras taking up space inside with a 1" port at 1" long ( or 1.5" port at 2.75" long) will put them down at a FB of ~58 Hz and a F3 of ~49 Hz. Not too shabby, I'd say.

The interior measurements of the box, I like the Acoustic Ratio of ~11"x8.5"x7". That way, you can choose whatever thickness you want.

For a companion woofer, I've looked at a lot of drivers from 4" & up, I think that these two 6-1/2 drivers look promising in 1 CuFt boxes that can be fit around the MTMs. The Goldwood would have FB of ~44 Hz, F3 of ~37 Hz with a 1.5" port 1.4" long and a 4.7 dB peak near FB. The Peerless would sit both the FB and F3 at ~42 Hz with 2" port 3.2" long with a 2.2 dB peak near FB. I kind of like the Peerless a bit more atm, just on spec. Of course the 1CuFt box is just a way to keep it small and volume is subject to change and recalculation.

Again, that is just an out loud thought/suggestion, not a requirement. 

For the XSim question, just load the 0 degree frd file. That is the one you should be working with. The other ones are the off axis measurements.

 

PS, almost forgot, are these dimensions doable in your room or do you need something smaller? Wouldn't hurt to draw a scale mock-up of your room to see how it all fits, or if a bit of a rethink my be needed. It'd be a bummer to go through all this to find out it's crammed in tight. You say you are in an apartment, so I don't have any idea what you can and cannot do with your area.

-Charlie


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Dameo182
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16/10/2020 7:29 am  

Thankyou for all of that, the integrated but detachable idea is a good one, maybe a little too complex for me though, what i think i will do is firstly make all of the mtm speakers, and the sub so that i can get it working at least. Then add the extra bass as you mentioned at a later date, im limited for time as my girlfreind is due to give birth in december, so whatever i make has to be finished by then as all my free time will be given to my son, at least for the first few months. So i have 5 mtm to make and atleast one sub, whuch tbh i havent even started to design yet, i wanted to use the w5 as i said before but its 40watts rms is a drawback, can you think if theres away i can bring that into the mix or just go for a bigger sub? 

 

The working out you did is pretty much what i got too, i planned to make the box 13x6x8.5 internal giving .343ft. With a 20mmx40mm port at a leng if 46mm.Trying to keep the box a bit smaller but i guess i sacrifice bass by doing that though, maybe they will still sound ok, as tge one i made for my girlfreind soubds really good, but ut is in a slightly bigger box. 

I definately plan to do like you say about adding the extra woofer to help with bass, its a good fix if the mtm are lacking a bit, im stuck on the crossover at tge minute though, i cant seem to get xsim to put a baffle step circuit in, it only puts the componsnts in in series when i try to add them and there is no already made circuit to add to it that i can tell, do you know how i put componants in in parallel on that software? 


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TVOR-Ceasar
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16/10/2020 8:49 am  

Ironically, I have the PC83-4 files from when we started the "Who wants to design a speaker with me?" thread. I tried throwing together a quick MTM 1st order X-Over using the ND90, and there was a big dip at about 16.5 KHz. Out of curiosity, I pulled the tweeter out of circuit and the graph looked amazing. I wish I had some hands on experience with them to really see what's going on. 

Does anyone here have experience with the PC83-4? We'd like to hear from you.

As to the Baffle step and XSim, I am still learning them myself. I'll let you know when I figure that out.

( Still learning WinISD as well. You are never too old to learn. )

 

Almost forgot - the subwoofer. You should be connecting that to the Sub Out on your AVR, which is at line level. Therefore, it will be self-powered by it's own plate amp. We can work on that once you get the main speakers worked out.

-Charlie


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Dameo182
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16/10/2020 10:43 am  

@tvor-ceasar

 

I hadnt noticed the dip, as i said i cant get that far in xsim yet lol i havent fully decided on a tweeter yet, i was planning to try crossover with multiple different ones to see which seemed to match best, but i think i might go for the hivi t20, if i can ever get a baffle step circuit into xsim 🙄

Ahh i hadnt realised the sub worked like that, i assumed the avr was what powered it, im glad you told me that, so the w5 is a possibility then? But as you say, get the mtm's sorted first lol

I really appreciate the help your giving me on this, my system of speakers is sure to sound way better now than if id gone at this alone 


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