What crossover freq. for these 3-way drivers

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emretelci

emretelci

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Joined 2015
#1
This is my first time on building speakers. I have made my own 25 tube amplifier, it sounds great and I feel I need good speakers for it... So here is my plan.

RS28A-4 1-1/8" Aluminum Dome Tweeter 4 Ohm
1,200 - 20,000 Hz
RS28A-4 1-1/8" Aluminum Dome Tweeter 4 Ohm Specification Sheet


RS125P-4 5" Reference Paper Woofer 4 Ohm
70 - 12,000 Hz
RS125P-4 5" Reference Paper Woofer 4 Ohm Specification Sheet


RSS210HF-4 8" Reference HF Subwoofer 4 Ohm
27 - 1,000 Hz
RSS210HF-4 8" Reference HF Subwoofer 4 Ohm Specification Sheet


For the crossover I want to use a 3-Way Crossover which is 375/3,000 Hz
XO3W-375/3K 3-Way Crossover 375/3,000 Hz
Dayton Audio XO3W-375/3K 3-Way Crossover 375/3,000 Hz - Crossovers - Crossovers & Components - Loudspeaker Components


And I want to add a passive radiator which is 8”
SD215-PR 8" Passive Radiator
Dayton Audio SD215-PR 8" Passive Radiator - Passive Radiators - Loudspeaker Drivers By Type - Loudspeaker Components


So do you think I am using a correct crossover? I am learning, and open to suggestions.
 
#2
Forget about an off-the-shelf crossover. The idea that choosing a set of drivers and using an off-the-shelf crossover would create a good sounding speaker is foolish.
For a first build I suggest you to build a proven design, a speaker designed by a reputable designer. See for example Zaph Audio or Troel Gravesen. You can study those designs, to learn what the components of a crossover are used for.

Ralf
 
#3
😛 moreover, the crossover is specified, as usual, for the nominal target Z, in this case the bobbin for lowpassing the woofer has a tap for halved Z drivers.
"A unique design feature of the low-pass section allows for the use of 4 or 8 ohm woofers, perfect for building a multi woofer system*. The midrange and high-pass sections are rated for an 8 ohm load"

*This means that you can use two 8 Ω woofers in parallel...
 
#5
However, nothing's wrong with 4 Ω speakers, except that they draw more current from the amplifier...
Related to the crossover, the high pass capacitors simply double the value and the coils for lowpass halves ...
Of course it's all nominal...in reality a complex load with low Z brings an amplifier to its limits, being the high current the limit for the active device.

For tubes, I guess 8 Ω is always welcomed
 
#6
Thank you very much.

Here is my final list which is a lot more logical than the previous one... I have cancelled the passive radiator also... Now all of them are around 90dB so no need for an attenuator...


RS28A-4 1-1/8" Aluminum Dome Tweeter 4 Ohm
RS28A-4 1-1/8" Aluminum Dome Tweeter 4 Ohm Specification Sheet


RS125P-4 5" Reference Paper Woofer 4 Ohm
RS125P-4 5" Reference Paper Woofer 4 Ohm Specification Sheet


DCS255-4 10" Classic Subwoofer 4 Ohm
Dayton Audio DCS255-4 10" Classic Subwoofer 4 Ohm - Classic Series - Loudspeaker Drivers By Series - Loudspeaker Components


XO3W-375/3K 3-Way Crossover 375/3,000 Hz
Dayton Audio XO3W-375/3K 3-Way Crossover 375/3,000 Hz - Crossovers - Crossovers & Components - Loudspeaker Components


My only question is, for the mid (5") do you think I should use two of the 4 ohms. Because the 8 Ohm version is 87 dB will be lower than the rest of the drivers... 4 Ohm one is 90dB...

And same question is also for the tweeter. They don't have the 8 ohm version of those dome tweeters, so should I connect two of the same tweeters in series? I fell it might be awkward.

Instead I may use only one 8 Ohm tweeter like
PT2C-8 Planar Tweeter
http://www.daytonaudio.com/index.php/loudspeaker-components/loudspeaker-drivers-by-type/tweeters/pt2c-8-planar-tweeter.html
I would not like this because it is 94 dB and I should use an attenuator and also after 10kHz, the sound drops...
 
#7
giralfino said:
Forget about an off-the-shelf crossover. The idea that choosing a set of drivers and using an off-the-shelf crossover would create a good sounding speaker is foolish.
For a first build I suggest you to build a proven design, a speaker designed by a reputable designer. See for example Zaph Audio or Troel Gravesen. You can study those designs, to learn what the components of a crossover are used for.

Ralf
Click to expand...

😱
 
#9
Firstly, the 8 inch woofer had a much flatter response curve and will cope fine, far better than the 10 inch imo.

The Mid range driver is compromised as far as power handling is concerned and thermal compression will be an issue if played loud.

Why not go active? (sorry I just read the valve amp bit at the beginning). The Xover frequencies are fine, providing you don't use the 10 inch driver.
 
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#11
Now all of them are around 90dB so no need for an attenuator...
Click to expand...
You do need to attenuate both mid and tweeter at least by 3dB up to 6dB because there is the baffle effect. It seems you know nothing about speaker design. If you want to design please read at least one of the sticky posts in this forum about designing without measurement.

Ralf

Tweeter and mid are fine, I would choose a true woofer and not a sub if the crossover frequency will be around 300Hz.
 
#13
1) You can get a good education, AND great speakers for your efforts, if you find a well reviewed proven design to copy.

2) 1" + 5" + 8" ported is a very popular combination in many speaker brands: Dayton, SBAcoustics, SEAS, etc...
Troels has several to study.... you should be able to find a Dayton diy on the web.

SBAcoustics-3WC

3) The RS225P 8" Reference Paper Woofer is the typical selection with a 5" midrange. goal = "high details"

4) If you really want powerful bass from a subwoofer like the Dayton DCS255 10" use a 6.5"-7" midrange with a lower Xover point to achieve good balance. goal = "high dynamics"


Floor Standing cabinet? Bookshelf? How big?
Can your amp handle 3-ohm loads? You have selected 4-ohm drivers.
 
#15
jf4828 said:
I think that your plan is logical based on the information you know at this time. That said, the experienced folks on here will likely all tell you the same thing. An off the shelf crossover has a very low chance of sounding very good. Here is a good reference:
crossovers

If you would like some kit recommendations just let us know...
Click to expand...

Thank you all, I am learning at the moment, and I thought it was a good start to buy a ready crossover, and later, tweak it. But now, after reading your comments, I have decided to start with a well known design... I also won't decide the drivers myself, I think it is good to stick with a well known design...

So yes, please, a recommendation about a good kit would be great. Having more bass is what I am looking for...

I am also looking at this design SBAcoustics-3WC

Thanks again...
 
#18
Actually I must say, what I want is "studio reference monitors" first. Than some bass...

After I have finished making my tube amp, I was happy with the sound until I have decided to add a subwoofer to the system. Suddenly I have realised that having bass was also very nice... I am mostly playing electronic music. I love the clarity of reference monitors.
 
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#19
emretelci said:
My budget is around 900$ for the drivers and crossovers...
Actually I must say, what I want is "studio reference monitors" first. Than some bass...
Click to expand...

Several respected designers praise the Satori line of drivers from SB-Acoustics.
CHECK OUT kits which use either the: 6" Satori MW16P or 7" MW19P midrange in a sealed cabinet, plus a 10" or 12" musical woofer that fits your room requirements.

What cabinet shape?
....do you favor a 2-piece BiKini so you can mix-and-match top and bottoms as your audio figure changes?
OR
...do you favor a more substantial 1-piece to keep everything in place.
=======================
Meniscus audio has Jeff Bagby's Kairos(slant baffle) and Adelphos(straight baffle) Satori Monitor kits, and also sells a 10" add-on woofer. On a tighter budget? Switch in a lower cost tweeter like the SB29RDC-C000-4
Adelphos / Pair

Joachim Gerhard designed the free Kalasan kit for SB-Acoustics
http://www.diyaudio.com/forums/vendors-bazaar/220330-sb-acoustics-satori-monitor.html

https://www.lautsprecherbau.de/Maga...Formula-of-small-speakers_8636,en,901195,9871

www.audioexcite.com Satori Two – Monitor
 

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