Big 2-way Speaker guidance

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#21
Fredrik93 said:
Okay. What I guess I don't understand just looking at the SPL graphs is why it would be an issue to crossover a tweeter down at 1k. Assuming I can create a crossover that starts and ends where both woofer and tweeter are flat.
Click to expand...

You aren't necessarily going to see this on the SPL graph of the tweeter. In some cases it will be obvious because it may start to drop off at 2.5kHz and is clearly not suitable. But in your case with the SB26STWG the SPL looks pretty flat to 1kzHz.

BUT...two things.
  • The tweeter has an Fs of 780Hz and the rule of thumb is that you cross over an octave above Fs, this would have you crossover at 1560Hz or higher. (The rule of thumb isn't perfect, but crossing over a tweeter with an Fs of 780Hz at 1kHz is not a good idea.)
  • This tweeter has an xmax of 0.6mm which is actually quite good. If you look at an excursion calculator (like THIS ONE) you can see that for a 1" piston to play 96db at 1kHz requires an excursion of 0.7mm. However, to play 96dB at 1.5kHz requires only 0.3mm.
Note the first review at Soundimports: "Fairly good horn, distortion is minimal above 1300hz even at 96db, measurements below it increases quite fast."
 
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#23
Fredrik93 said:
I planned on not going for a ML-TL, just have a port vent in the back.
Click to expand...

You can plan all you want, but given the shape it isan ML-TL. Yoiu can fight it, but it will still have quarter-wave eigen modes.

I assume there are basically zero tweeters that would do 250 or even 500?
Click to expand...

maop5-4.jpg


https://www.madisoundspeakerstore.c...agnetic-arc-oxidized-full-range-matched-pair/

At the other end of the budget spectrum. Alpair 5.3 in-between,

https://www.madisoundspeakerstore.c...mark-audio-chn50-3-magnesium-cone-full-range/

At 250 Hz you may be somewhat limited on how loud. %00 Hz they will be fine. We have used the 4” Alpair and it is happy at 250 Hz.

dave
 
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#24
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#25
Fredrik93 said:
I'm a starting to consider adding a mid woofer since everyone makes the case that it would be easier for the crossover. Would I need to create a separate enclosure in the box if I add a mid range driver? Assuming I would have woofer woofer mid tweeter.

If I added for instance: https://www.soundimports.eu/en/sb-acoustics-sb15mfc30-4.html

DriverFromTo
2x HiVi-M8N-120300
SB Acoustics SB15MFC30-43002-3k
SB Acoustics SB26STWGC-42-3k20k
Click to expand...
Hi,
I see where you are going.
First choose the driver you want. In other words, the mid that will give you the range of voices, women, opera singers, etc. It can be a mid woofer (also with low frequencies) or not. This will make you decide if you need just a 2-way, ok. But so far from the beginning of the thread you are more concerned about WinIsd which doesn't tell you anything about it. And never cut at 1kHz or you ruin the image and phase. So, choose a driver with regular output, non-metallic (so as not to show high-pitched sound) and preferably without breakups that will give you a nightmare when listening and trying to make crossovers, like others said.
 
#29
A4eaudio said:
You aren't necessarily going to see this on the SPL graph of the tweeter. In some cases it will be obvious because it may start to drop off at 2.5kHz and is clearly not suitable. But in your case with the SB26STWG the SPL looks pretty flat to 1kzHz.

BUT...two things.
  • The tweeter has an Fs of 780Hz and the rule of thumb is that you cross over an octave above Fs, this would have you crossover at 1560Hz or higher. (The rule of thumb isn't perfect, but crossing over a tweeter with an Fs of 780Hz at 1kHz is not a good idea.)
  • This tweeter has an xmax of 0.6mm which is actually quite good. If you look at an excursion calculator (like THIS ONE) you can see that for a 1" piston to play 96db at 1kHz requires an excursion of 0.7mm. However, to play 96dB at 1.5kHz requires only 0.3mm.
Note the first review at Soundimports: "Fairly good horn, distortion is minimal above 1300hz even at 96db, measurements below it increases quite fast."
Click to expand...
Gotcha... This all makes it very hard for beginners haha... But note taken.


You can plan all you want, but given the shape it isan ML-TL. Yoiu can fight it, but it will still have quarter-wave eigen modes.
Click to expand...

Alright, I don't know the exact definition of ML-TL, I assumed it would need a barrier inside the closure to qualify (?).


ChrisABC said:
Midwest Audio Club
https://diy.midwestaudio.club/discu...rivers-late-night-early-morning-kind-of-thing
Click to expand...
That's depressing to read, is it common for manufacturers to basically be way off? Or is HiVi just not a very good brand that I should try to stay away from? Simulating these values in WinISD gives an awful graph... I'll look for some other woofer driver.


Freedom666 said:
just take a small fullrange like visaton b80 then you can cross below 1khz without headache.

and maybe try series filter 6 and 6db but I don't know which software can emulate this.

Maybe Boxsim which is for free if you use visaton drivers only. they are already measured with all data in boxsim

https://www.visaton.de/en/literature-software/software
Click to expand...
That one looks good. I was kind of hoping to use something other than a fullrange driver this time around. My two previous ones both had Alpair full range, which feels like it becomes too easy if that makes sense hehe.

Jesus, there are so many words I don't know haha. "series filter 6 and 6db". I have to chatgpt like 50% of the comments to understand what everyone is saying 🙂

-------

Appreciate all the feedback everyone 🙂
 
#32
In the end I ended up going for a 3 way and bought the following drivers. It felt like I would sacrifice too much if I went with a 2-way, so why not just go for 3, even though the cost is a bit higher.


Order SB Acoustics SB26STWGC-4 Dome Tweeter - SoundImports x2
​
Order Dayton Audio SIG120-4 Mid-range Woofer - SoundImports x2
​
Order SB Acoustics SB23NRXS45-8 Bass-midwoofer - SoundImports x4
​

I've started thinking of crossovers even though I haven't started building the box yet, I'm not really sure if I want to go for a active vs passive crossover setup.

I like the idea of getting something like a miniDSP flex eight since it seems to give a lot of flexibility.

This way I could avoid putting in a passive crossover in the box, I get good options for EQ which I think would be helpful for my apartment being a fairly odd shape. I also like the idea that there is less pressure on making the crossovers perfect in case I would make some mistakes and would allow me to optimizing it after the drivers have been used for a while etc.

The obvious downsides I see are that the cost would be quite a lot higher. MiniDSP is around €800. I would need amplifier for 6 channels, which I assume is at least €600. On top of this I maybe would need to get a new home receiver because it didn't seem like mine has the outputs for the miniDSP or potentially if its possible to use a HDMI Extractor...

Or I just build a passive crossover like I initially was thinking.

Any thoughts 🙂 ?
 
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