First-Timer Home Theater Speaker Build

So your response in the 5th pic looks very good but your upper xo point is at about 4kHz whereas it's at about 2.3kHz in the towers. That's quite a difference.

In terms of the lower xo point, something to note in XSim when you are using 2 drivers wired in parallel is that the point where the woofers in blue and the mid pair cross is not actually the xo point because the blue curve is showing the individual drivers and so it's in fact down 6dB from the sum of the woofer pair. So that xo point shown is lower than the real one. To see the real xo point, go into the Tune window for 1 of the woofers and increase the sensitivity by 6dB. The real lower xo point is at about 615Hz which is only slightly off from the towers at 577Hz so that one is fine.

So even though the curve looks good, compared to the towers you've got the CC mids contributing almost an octave more than in the towers which is going to sound slightly different in terms of front sound stage matching. Not the worst thing in the world but not ideal either. So I think I would try to change one of them so that both of them more or less match.

The bigger problem for me though is what are you going to do if when you listen to them, you find there isn't enough mids? Cause the mids are running full out already. So that could be a problem. When I'm working with a xo, it's important for me to have some flexibility to alter things both upwards and downwards in as simple a way as possible when it gets around to the listening stage and fine tuning and here you are kind of stuck.

Now in fact given the sensitivity of the drivers involved, things were always going to be a bit tight in this respect with the 3-ways (and that includes with the tweeter too), but the problem is being exacerbated just a touch again by the level that you are setting your woofer at which is again about that LF increase in the woofers due to the xo. Just as the perceived F3 is lowered because the fundamental is a little bit higher, so too are the mid and tweeter having a harder time keeping up because of that increase in the woofer level. Using that impedance compensation filter on the woofers not only both improves the perceived bass response as well as probably allows for a better blend with the subs but, because it requires that the woofer level to be lowered slightly, it also gives you a little more room to adjust the mids and tweeter in the upwards direction because both of them are going to need lowering as well to match the new, lower woofer level.

I know you don't want to use it and that's fair enough as long as you fully understand the consequences. But personally I would and have done so with good results in the past.

Just as an aside, I can't quite figure out why your woofers are rolling off at about 100Hz making them look like the FF measurement only and yet I don't see the null that should be present at the tuning frequency if that's the case. Not that that is making any real difference in the sim.

Also both of us were half right in terms of your V1 lowered impedance at about 5kHz. It was definitely the result of L4 being so small but also in conjunction with C4 being too large. The problem is that C4 is letting too much of the signal through and then the same is true for L4 but this time it's going to ground. And that's going to lower impedance and that's going to suck up the current at that frequency as well.

Btw, to fine tune the CC xo, you can save the tower summed frequency response and then import it via another driver into the CC sim and then compare. Or do it the other way around if you want to. And for a CC dealing with voices, I don't mind if there is a tiny increase in the mid frequencies and/or a tiny dip up in the sibilance region. If possible.
 
That is a very good point about the upper xo point. I have been trying to change both the tower and the CC sims to meet somewhere in the middle and I am just not getting it to look good on either of them. The natural curve of the tweeter on the CC really can only look like that to look good, if I try to lower the xo point there becomes a null around 5kHz that the mid just cant fill in either. Similarly, with the tower is I try to raise the xo point, there is a null around 3kHz. Both of these are large nulls btw, larger than 5dB.

So, that makes me think. Is it more important to get the exact voicing, or it it more important to get flat frequency responses?

That is a good point about if I dont have enough mids when I listen, then what? So I'll create a sim where I lower the tweeter and woofer a little.

Btw that null at the tuning frequency is not there because I incorporated the port in the blended response. Just like I did with the towers.
 
Alright so this is the best I could do to get them closer. The first screenshot is the tower and the second is the CC.

The tower xo point is now around 2.7kHz and the CC xo point is around 3.6kHz. At least closer this time.

The impedance on the CC gets pretty low, but I forgot to check that when I took the screenshot. It can easily go above 3ohms if I lower C3 to 22uF and lower C4 to 6.2uF or 6.4uF. That would put the xo point around 3.7kHz then.
 

Attachments

  • Tower A V.5.PNG
    Tower A V.5.PNG
    288.4 KB · Views: 86
  • CC(v.5.1).PNG
    CC(v.5.1).PNG
    287.2 KB · Views: 86
Re that darn pesky tweeter - it seems to me that with a lower xo point, it does better with a parallel LCR and with a higher xo point, it does better with a series one.

If there were no other choices, yes I'd favor the flat response even though the voicing might be slightly different.

It's easy to bring down the tweeter level if the mids aren't loud enough but how are you going to bring down the woofers? Maybe I didn't state this explicitly before but it's sort of a cardinal rule to keep the series resistance on the woofers as low as possible. So here I'm just talking about the inductor(s) never mind adding any kind of resistors. Adding additional series resistance to the woofers is very inefficient on the amplifier, it actually changes the box tuning somewhat (you can add resistance in Unibox to see the effects) not that that is going to make too big a difference here where your F3's have already been reduced significantly and you need to make sure you have resistors that can handle all the amp power and not burn up.

Yes good, add in the port but the blended response of the CC woofers isn't close to that of the towers - the CC is rolling off at about 100Hz instead of 50Hz.

Both the tower and the CC sims are good efforts with the topology you have decided upon. Impedance is low in the CC but with enough current in the amp it probably won't be a problem. A couple of things to note -> if you are going to look at the current graph, you should probably look at it with the maximum watts you expect to use, especially when looking at the lower frequencies. Additionally, XSim sort of assumes that equal power is being drawn by the speaker right across the whole frequency range which isn't actually true in most cases. Most music genres are recorded with levels that drop as frequency increases. Kind of makes sense when you consider Fletcher-Munson. So the lowest frequencies will need the most power whereas the higher ones will draw less so the lower impedance up in the high frequencies isn't quite as bad as in the lower ones. But of course, best is if they don't go low anywhere. This is also the reason why you can use series resistors with lower wattage ratings as you go higher in frequency too.

Attached is my version of the CC - flat and with just about the same xo points as the towers. Impedance and phase are good and both the tweeter and mids have room for adjustment both up and down. And port contributions are not diminished from the fundamentals. But I'm making design choices again that you don't want to make which is again, fair enough. They're your designs and your speakers and your choices. I'm just trying to lead you in the right directions.

Hope that helps.
 

Attachments

  • XSim CC v2.JPG
    XSim CC v2.JPG
    430 KB · Views: 83
Yeah isnt the tweeter just weird!!! Seemed like the right choice at the time haha.

Yeah that is a good point about adding series resistance, thank you!
So, if I want to bring the woofers down if I dont have enough mids, I have an interesting and maybe controversial question haha. Would it be okay to just lower the "Bass" EQ on the receiver a little to bring it down slightly?

Idk why the CC woofers roll off sooner than the towers tbh. I know they are tuned higher than the towers by like 20Hz. But I put in all the necessary values into Response Blender, so that's hard to say. Haha blending has been a discrepancy since the beginning with us. Makes me think how accurate it really is, or if I'm just doing it wrong.

So, since this is a home theater setup, a receiver is in order. I have been somewhat looking at some receivers that also have 4K HDMIs and have not found ones that explicitly state that they can handle around 3ohms. When looking for a receiver, do you have suggestions on exactly what to look for or if there are some secrets on how to determine if it'll be sufficient?

Also a great point and reminder about low frequencies demanding more power. So the impedances down low are going to be more crucial than the high frequencies.

Your CC sim does look very nice and is really close to the tower xo points. I'm going to try that on what I have and see what I get, cuz from my experience I would still get those nulls like I was talking about before.

Sorry if this phase of the speaker design has been frustrating at all for you with trying to work with me. It has been abundantly clear to me in a lot of ways that these speakers need to get done asap and that I need to start my career and find a real job. So I apologize if I more or less has been "pushy" or not as easy to work with. As always, I appreciate and value your help in this very very much and do not know where I would be with this without your help along the way! Thank you!!!

I will try your CC sim and see what I get. See if I want to change it, but by the end of today I will be ordering the xo components! Which is honestly very exciting:D
 
If the receiver is rated at 4ohm nominal, it will be fine with minimum of 3ohm loads. That's an international standard. Slightly lower as well if there is enough current available. Sometimes this is stated explicitly as it should be but sometimes the easiest way to figure it out if it's not clearly spelled out is to look at the pictures of the back of the amp - the minimum nominal allowed impedances are usually labelled at the speaker terminals.

As well, most HT receivers have a built in eq function like Audyssey or whatever it's being called these days. Some people like the results. Some don't. I think also having manual access to the eq is better than just the program doing it automatically and that the greater the number of eq points the better. So yes, the eq is an option but for eg, I always want to listen to music without the digital processing involved, using Pure Direct or whatever else that might be called these days, so again it may depend on your or your brother's priorities.

Simple bass/treble eq on the other hand just gives a general roll-off which may or may not match the problem that exists. Just rolling off the bass will also lower your already lowered F3 a little bit further as well. More so in fact than what is happening up between 100-200Hz.

So I already mentioned that what I do next is figure out the xo with different levels of mid and treble and see if any other components also need changing and try to either incorporate those into the design or have those on hand to add in. But with 3-ways, mostly just playing with the resistors on the mid and tweeter will usually do the trick.

Then lastly as I'm going through the parts order, I'll also have XSim open and I'll start to add in the correct values of the components that are actually available including the resistance of all the inductors just to make sure that any small changes don't negatively impact the results. Usually you keep the series inductors as low in resistance as you can while having more flexibility with the shunt inductors. You can sometimes save yourself a fair bit of money by using higher resistance inductors in those latter cases. I'll spend more money on the series caps too within reason and sometimes substitute lower priced ones for the very large values.

Again, I would not shy away from good iron core inductors for these speakers as well as those lower priced and lower sized caps where applicable. But hey, that's just me. :)
 
Forgot to mention that I find some alligator clips very handy for temporarily assembling xo's while testing them out. Twisting component leads together works as well but you have to be very careful with caps and resistors as too much movement of the leads where they exit/enter the component can cause them to break/detach. Not that big of a deal on a $2 resistor when you got extra handy but a bit of a pita on a $30 capacitor.
 
I expect that you are probably pretty busy tonight getting your xo's finalized and ordered and I don't want to flog a dead horse, but I feel maybe I was remiss in terms of providing enough information about LCR impedance compensation filters on woofers.

I think I probably learned more about them from Troels than anybody else. Unfortunately, he relatively recently started to remove the actual xo values from many of his designs but the xo topology still remains as well as pictures of the components he's elected to use. So here's a list for quick viewing of speaker designs with xo's relatively close to the woofer's first impedance peak that in his view required an LCR notch to flatten out the response. Look at the xo pictures too, can you spot how many iron core inductors he's using?

Illuminator-4
Illuminator-5
DISC-4
SBAcoustics 10
SEAS_NEXT4

All speakers with excellent quality drivers with LCR notches aimed at impedance peaks of more than 1 driver in the design. And here's one of the ones I could still find with the values still available. It's educational I think.

http://www.troelsgravesen.dk/ATS-4.htm

Obviously a blatant and last ditch attempt to convince you to go down this route but as always, it's up to you. ;)
 
Yeah I feel like the Bass eq on a receiver would not be good for me, but for my brother I have no doubts he would never notice.

Yeah I got a handful of extra resistor values, only like $1.5 each.

I also did go back to Xsim and put in the real values. Haha that did take some time, trying to work around the actual component values.

Also, I did go iron fore for the larger inductor values and also for the series inductors since they have a lower resistance. But for all the smaller inductor values, I actually found air core was either cheaper or only around $2 more than iron core.

And yeah I have a plethora of alligator clips to use, very useful!

I appreciate the links to the LCR impedance compensations filters! While I will not be using these in my design, it is still great information for the future! Someday I might make a pair for myself and go all out. Haha I'll most likely reach out to you if I do, if you are willing. Hopefully at that point just for big questions tho, I hope to get all the small stuff under my belt pretty well by then.Though, this might be many years down the road haha.
 
Sounds good.

Definitely air core inductors for the smaller values.

Keep me in the loop as you start your listening evaluations. One more thing I do at this stage is take more measurements of the in-room response of the speaker(s) from the listening position, no gating this time and then use that as a frame of reference for what I'm hearing and for making any changes to the xo.

But this time without any gating and with the mic much further away, your target response is no longer pseudo-anechoic, so a flat frequency response probably isn't ideal here. Instead you'll most likely get a falling curve as you go higher in frequency (plus more than a few wiggles) or to put it another way, you should see the effects of room gain and boundary reflections increasing LF output. This won't fill any holes in the bass response though, this is how it normally works -> anechoic, you want to target flat (more or less) and then in-room, it's going to look tilted downward in the HF's, which of course is needed to make up for the differences between how sound is measured by a mic and how sound is perceived by the brain (Fletcher-Munson again).

And as long as I'm still around and functioning, I'll be happy to assist you again with another project any time down the road.

Cheers
 
You are indeed correct. Given the xo's you require, there is very little likelihood of excessive heat. If there is, it'll be in the resistive components, primarily the resistors.

But if you want to be sure, listen to the speakers for an hour or so at max volume and then feel the xo's for temperature increases. If you happen to feel a resistor is too hot, you can always change it up for one with a higher power rating or else combine 2 resistors in parallel to half the load each one sees (values need to be doubled though of course).
 
Hey!

Wow it has been awhile and a lot of life has happened.

Thank you for the inductor link! That is some good info and good insight as to how the distance and orientation directly effects them.
The good thing I knew the basics of not putting inductors next to each other due to their magnetic fields. I for sure took that into account when assembling the crossovers.

But for an update! I tried out the speakers with the crossover components twisted together or lots of alligator clips. I also did a quick FR test and it came out pretty well! So, I sat with them for awhile and was honestly blown away. I decided to finishing it up and mounted the crossovers onto dense particle board that was about 3mm thick. All resistors and small capacitors I had glued them to the board, and with the bigger inductors and caps I glued and zip-tied them to the board. With solder lug strips as needed. I then screwed the board from the inside to the bottom of the speakers.

And to be quite honest, they sounded amazing. I am no true high-end audio aficionado nor do I have the experience of listening to high end audio systems enough to really know what to look for, but wow was I blown away by these. Everything in the music was really heard clearly, no harsh frequencies or lack there of. Everything was so balanced and it felt like my soul was being cleansed :D
My brother absolutely loved them and during Thanksgiving my family loved them and my Uncles who are audio guys as well were blown away by it.

The CC made it easy to sit back and watch a movie without saying "What did he/she say?".

It was amazing and I really enjoyed it. I wish you could have listened to them! But, alas, they are gone off to Texas now. Haha I did not feel I would miss them until I listened to them, now it's tough that they are gone. But, thats how it goes!

So, yeah thats what I got to share with you! Sorry it took so dang long to do so haha, holiday season is a busy one.
I hope you are doing alright!

A final question I have for you is this; how much do you think these speakers are worth?
My brother and I have already discussed a final price and he has mostly paid it by now. Which these were a special case since he did pay for all materials and even the measurement mic. But Im curious on what numbers you got in your head for if I were to make these again and sell these to someone else.
I know a big factor of that would be how they sound. For this, I'd say put them on a scale of high-end but not like crazy crazy high-end like some of the brands out there. So, think of it like two steps above a good Klipsch home theater system.
 
Hey Keil

Welcome to the world of diy speakers. They can be pretty fri99in awesome when you get them right.

I am so glad for your success with them. You undertook one heck of an ambitious project for a first timer, something that over the years more than a few people here have said shouldn't be done or even can't be done successfully. You put in the time and effort, persevered when problems arose and it sure sounds like you ended up with something you can be very proud of. Well done.

As for their monetary worth? I don't really keep abreast of current speakers out in the marketplace any more so I'm not really the best person to answer that question for you. And obviously, I haven't heard them. Nor those specific drivers in any other builds either. You'll want to obviously cover the cost of all the materials involved as well as get a decent return on the time you invest with the design and construction. If you wanted to do these exact speakers over again, well, the design aspect is already done so you just need to figure out how much time it takes you to build them. And really I think you are going to want to be pretty fast at it in order to be at all competitive in the marketplace. An acceptable price may vary with the quality and type of finish as well. Look at both the standard speaker market out there a well as some of the smaller sort of direct to the consumer on-line enterprises, like Salk Sound or Philharmonic Audio for eg, to maybe get a better feel for the whole thing.

Once again, very well done. (y)👍
 
Yes and thank you for the mentorship and extensive help during the build! Without you it would have taken much longer and key steps would have been overlooked. So I thank you for that!! Truly.

Okay sounds good. I have had a lot of people come to me asking for speakers now haha. While I don't feel worthy enough to make ones that would be the best of the best. Please do like the idea of completely custom speakers. Since all speaker companies and even boutique/high-end companies only have their stock/model options to choose from, my model would be to make custom speakers per client basis. Finding gaps in the market ya know.

Anyways, this is all just a thought tho. Nothing it being put into action. For now, I have to get a real job and start my life making real money while gaining experience. Then maybe down the line, if the stars align haha, I might legitimately think about starting a speaker company. I mean I do already have a name and logo haha. But I know of course these tons more that would entail. (.... like a CNC machine for one haha)

Again, thank you Chris!