MemberJune 24, 2022 at 10:04 pm
I’ve drawn up the enclosure now, which I will post tomorrow, well at least one design of it, I may change it after some thought as it’s turned out to be quite big due to adding a higher wattage in the signal power, I landed on 15watts in the end just because I’m constantly second guessing my decisions, as I really have no idea how that really works. But because of that the port has to be huge in comparison to using 1 watt.
Anyhow I have a couple more questions about those BMR drivers ,
•Does it need its own sealed enclosure even though it’s acting as a tweeter, I plan to cross around 4k, unless I’m advised to change that.
•Does it also need to be flush mounted to help with diffraction, if not what is the reason that it can be proud of the baffle?
•Also regarding the cone excursion, after trying to find answers for hours about the ins and outs of adding it into winisd, I found a few comments that every driver should be protected from over excursion under the tuning frequency of the box, to stop damage and distortion, but I have no idea if that is really true and if so how I would even do that?
I realise I’m asking a lot of questions and I do appoligise for causing you guys to spend time explaining for me but just so you know I really do appreciate any help that you give to me. This little project is showing me once more that I still have a lot to learn!
MemberJune 26, 2022 at 12:35 pm
I’m just posting this image to get your opinions on the design, I’m not sold on the ports being towards the middle, although they with be covered by an inset mesh panel. Haven’t decided on the colour or finish I’ll use yet this is just a quick drawing done to show my idea.
- This reply was modified 1 month, 2 weeks ago by dameo182.
AdministratorJune 26, 2022 at 1:56 pm
I really like it. I might consider rear porting though (depending on location) as you might be able to increase your bass response by gaining off the wall behind it. Overall I think it is a great design. And I really like the idea of crossing over low enough with the Dayton Audio that you won’t have to worry about the off-axis as much as you would with a normal MTM. This is a really great design.
MemberJune 26, 2022 at 4:15 pm
I did consider putting the ports to the rear, but the front baffle is such a large panel that it looked a bit empty without the ports, really I added them to the front for aesthetic reasons and I just hope it doesn’t reduce the bass output too much. I also wasn’t sure about the 4k xover point until your reply so I feel a little better about that now, thanks for giving the design a once over for me.
AdministratorJune 26, 2022 at 10:54 pm
@dameo182 I misread the crossover point. I read 400hz not 4khz. Personally the major advantage of the BMR is being able to use a lower crossover point to minimize the MTM effect. I would still try to cross closer to 500hz or below if I could. Or at least try it and see what you think of it.
MemberJune 27, 2022 at 12:05 am
I’m glad you corrected me 😄 yeah it makes sense, I’ll do that instead, I just assumed it would only be the highest frequencies that had to be sent through the bmr driver and the nd65 would handle the Voices, but that’s the reason I come here for advice 👍
ModeratorJune 26, 2022 at 2:01 pm
I like the look of that. Not too sure how it’ll sound, but I’m sure way better than the TV speakers.
One thing g that popped into my head was: Have you given any thought to angling the faceplate down toward the seating position? That way you aren’t dealing with off axis sound lobes. With the mounting position and the fact its in a caravan, I’d think the listening position would be at least 30° below the soundbar.
Just a thought.
MemberJune 26, 2022 at 4:25 pm
What about it makes you wonder how good it will sound? I ask as I want to do the best possible job I can do with this build so if you noticed something that I can improve on it would be a great help. Also I did consider tilting the front baffle downward but I’m hoping (if this turns out to be good enough) to try to sell a couple of these, just to family and friends, and in that situation I would have to redesign the speaker and probably the xover slightly to allow it to be used as a normal soundbar, as far as I am aware most people place them under the tv, I’ve never really been a fan of soundbars so I’m guessing on that though 😄
ModeratorJune 26, 2022 at 5:06 pm
I don’t have much first hand experience with MTM soundbars. Most I’ve used or tried were just single drivers per side.
For pure frequency reponse, I’m sure they’ll be impressive for their size. And all the regular MTMs I’ve heard have amazing Soundstage. From what I’ve read, the sideways versions become narrow, but there are many from the big companies out there that are this way, so it must be quite usable. Nick ( @123toid ), what’s your further take on them? I know you definitely have experience there.
As far as tilting the front, I doubt you’d have to change anything. I only thought of it because you’d tend to be higher above the ear with that mounting than you would be below the ear with the under screen mounting. Maybe the sideways lobing will be a benefit in this situation. 🤔
MemberJune 26, 2022 at 6:14 pm
I think the main reason @123toid suggested I use the full range BMR driver as the tweeter is mainly to improve the fact that it’s a horizontal mtm design, those drivers seem to do some sorcery with the sound from how I understand them, and yeah I was considering just putting one woofer and one tweeter on each side, to bring down the cost and because I had heard that mtm horizontally we’re lacking in the off axis. But I went with the MTM design mainly because I wanted better power handling by sharing the load and also after modelling the single woofer enclosure it was way over the xmas limit on the cone excursion and I’m yet to understand why since it’s suppose to handle 15watts rms, I’m sure I’ll figure it out at some point though. I understand it a little better than I did after your input though.
My reasoning for keeping the baffle level at the front was because I have the height limit, and to keep that height with a pitched baffle I’d have increase the length from top to bottom, I Know its probably only by a few mm but I’m not sure how much you can change the dimensions of a baffle before it changes the response with the designed crossover, so to then make one with a 90° baffle for someone else I thought might mess with the response and need crossover adjustment. I’m probably overthinking it again though 😄 luckily it’s easy to change in fusion at this stage.
AdministratorJune 26, 2022 at 10:57 pm
@tvor-ceasar You are absolutely correct about the horizontal MTM. I mentioned the BMR since it has a very wide dispersion pattern (almost 180 degrees). If it were me doing it, I would cross the BMR’s over low (200-500hz range to get the wide dispersion with minimal issues you typically have with a horizontal MTM.
@dameo182 That is the main reason I suggested the BMR. The high end will definitely be better with this type of build. As I mentioned before, the lower you can cross the BMR’s over the better it’ll sound to all seats.