I'm designing a 2.0 speaker set (2-way) to use in my office, as computer speakers. I've looked around for a small woofer that can deliver low frequencies and yet can be contained in a fairly small case.
I'm very new to designing speakers (never done it) and have only had a few evenings to read about crossover design, box design etc. Therefore I'm interested to hear what you guys have to say about my design so far.
The woofer I decided to use is the Dayton Audio ND65-8 2-1/2" Full-Range Driver. It seems to be a good size, can reach low-ish frequencies and does not require a very large case. According to specs on Soundimports.eu the optimum vented case should be 0.05ft3 (about 1.4liters) at which their calculations can reach 55Hz. It also has a lot of great reviews.
I looked around for a tweeter to go with the woofer, and found the Dayton Audio AMT Mini-8 which to me seems like a nice match with frequencies up to 4kHz, beond human ears capabilities. It also has great reviews, and looks fairly nice and "exotic" to me since I only own speakers with domes and horns. Would be fun to try out something different.
After reading reviews of the two speakers, and a few forum threads, I'm thinking of setting the crossover at 6000Hz. Normally, from what I understand, a tweeters crossover should be Fs*2. I've read that AMT tweeters dont need the same crossover calculation, but from the spec sheet graphs on the woofer it seems like a nice enough frequency to do the swich on.
I've used some online calculators for the crossover, and tried to mach that as closely as I can with the components available at Soundimports.
These are my results:
First order 2-way crossover
C1= 3.3125µF (3.3µF available)
L1= 0.2123mH (0.2mH available aircore)
L-pad (to bring down the tweeter sensitivity):
Should be -7.2dB but couldnt find the correct componets which led to -7.8dB instead (bad choice?)
R1=4.7409Ohms (4.7Ohms available)
R2=5.4993Ohms (5.6Ohms available) bad?
The speaker box I've designed has a volume of 1216,6 cm³ (or 1,2166 liters). I know it's a tad bit too small, but I'm designing small computer speakers for a small office. A bit of polyfill dampening will do the trick?
Height: 20cm (internal 18cm)
Depth: 12cm (internal 10cm)
Width: 6cm to 10cm (internal 4cm to 8cm)
Material: 1cm MDF ("kerfed" sides)
The vent/port will probably have to be purchased elsewhere, since the smallest I could find at soundimports was 1". To not have a tube longer than the case I'm thinking 1.8cm diameter.
Since I'm very new to speaker design, about 3 late nights, I thought I should share my design and see if anyone has any objections or great ideas. I might also have misread when researching speaker design rules, and if that's the case maybe you guys can save me from destroying the componets or creating hideous sound waves. I know I'm probably stupid to go with a curved case as my first build, but I dont want to make just another box.. Hopefully the box calculations are "similar" enough.
The reason for choosing Soundimports as my one and only source is laziness and an allergic reaction to multiple shipping costs and delays
Local Swedish stores seem to have a very low range of speakers. If the crossover component compromises are a bad idea, I can live with finding better ones elsewhere. Not too keen on import fees to Sweden though.
This was a giant wall of text, I know. I apologize for that and any weird english I way have used (aka. Swenglish) and I'm thankful for any input.
I'm very new to designing speakers (never done it) and have only had a few evenings to read about crossover design, box design etc. Therefore I'm interested to hear what you guys have to say about my design so far.
The woofer I decided to use is the Dayton Audio ND65-8 2-1/2" Full-Range Driver. It seems to be a good size, can reach low-ish frequencies and does not require a very large case. According to specs on Soundimports.eu the optimum vented case should be 0.05ft3 (about 1.4liters) at which their calculations can reach 55Hz. It also has a lot of great reviews.
I looked around for a tweeter to go with the woofer, and found the Dayton Audio AMT Mini-8 which to me seems like a nice match with frequencies up to 4kHz, beond human ears capabilities. It also has great reviews, and looks fairly nice and "exotic" to me since I only own speakers with domes and horns. Would be fun to try out something different.
After reading reviews of the two speakers, and a few forum threads, I'm thinking of setting the crossover at 6000Hz. Normally, from what I understand, a tweeters crossover should be Fs*2. I've read that AMT tweeters dont need the same crossover calculation, but from the spec sheet graphs on the woofer it seems like a nice enough frequency to do the swich on.
I've used some online calculators for the crossover, and tried to mach that as closely as I can with the components available at Soundimports.
These are my results:
First order 2-way crossover
C1= 3.3125µF (3.3µF available)
L1= 0.2123mH (0.2mH available aircore)
L-pad (to bring down the tweeter sensitivity):
Should be -7.2dB but couldnt find the correct componets which led to -7.8dB instead (bad choice?)
R1=4.7409Ohms (4.7Ohms available)
R2=5.4993Ohms (5.6Ohms available) bad?
The speaker box I've designed has a volume of 1216,6 cm³ (or 1,2166 liters). I know it's a tad bit too small, but I'm designing small computer speakers for a small office. A bit of polyfill dampening will do the trick?
Height: 20cm (internal 18cm)
Depth: 12cm (internal 10cm)
Width: 6cm to 10cm (internal 4cm to 8cm)
Material: 1cm MDF ("kerfed" sides)
The vent/port will probably have to be purchased elsewhere, since the smallest I could find at soundimports was 1". To not have a tube longer than the case I'm thinking 1.8cm diameter.
Since I'm very new to speaker design, about 3 late nights, I thought I should share my design and see if anyone has any objections or great ideas. I might also have misread when researching speaker design rules, and if that's the case maybe you guys can save me from destroying the componets or creating hideous sound waves. I know I'm probably stupid to go with a curved case as my first build, but I dont want to make just another box.. Hopefully the box calculations are "similar" enough.
The reason for choosing Soundimports as my one and only source is laziness and an allergic reaction to multiple shipping costs and delays
Local Swedish stores seem to have a very low range of speakers. If the crossover component compromises are a bad idea, I can live with finding better ones elsewhere. Not too keen on import fees to Sweden though.This was a giant wall of text, I know. I apologize for that and any weird english I way have used (aka. Swenglish) and I'm thankful for any input.
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My experience with the Mini-8 has been disappointing. I have tried crossovers in the 5kHz to 6kHz region (this is my preferred crossover region). There is generally good treble, but always with the presence of strong sibilance. This was found with two different pairs of tweeters, one in an active setup and the other in a passive speaker.
Here is a HolmImpulse measurement with THD.
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I didnt see anyone in the reviews mentioning that, which is odd. I had high hopes. What tweeter would you suggest I use in this project instead?
They are a bit bigger, but doesn't seem to require more volume than the DA ND65s. I could easily modify the box a bit to house them. I'll do some calculations and see how low they can go with the same-ish volume and vent.
The Dayton Audio ND91-4 seem to be pretty close to the preerless, but is specced at 65 to 17kHz, while the peerless from 70Hz to 6kHz. The ND91-4 seems to give a little more wiggle room for crossovers, if needed? Would the ND91-4s be a good replacement aswell, or am I missing something important?
I have at hand a pair of "Peerless by Tymphany XT25SC90-04 1" Dual Ring Radiator Tweeter". I have yet to test them, so I have no recommendations as yet.
Peerless by Tymphany XT25SC90-04 1" Dual Ring Radiator Tweeter
If you are using the ND65-8 fullrange driver, why add a tweeter?
For computer use a small fullrange is more than adequate. I use the SB65WBAC25-4 in 1.36 litres with a 18mm x 75mm port (Fb=79Hz) and gives an F3 around 65Hz. Plenty of top end and bottom end for this application.
Just a thought as can save money and time with a tweeter and crossover.
For computer use a small fullrange is more than adequate. I use the SB65WBAC25-4 in 1.36 litres with a 18mm x 75mm port (Fb=79Hz) and gives an F3 around 65Hz. Plenty of top end and bottom end for this application.
Just a thought as can save money and time with a tweeter and crossover.
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I was looking at the Helium project by scottsehlin based on the Daton ND91-4 and Dayton ND16FA-6 and figured why not just build that but with my own enclosure? Since its my first time building a speaker, crossover etc.
This one: Helium - a true micromonitor -
Techtalk Speaker Building, Audio, Video Discussion Forum
I looked at the revised crossover design and tried to replicate it in Vituix and XSim, but my impedance curves does not look like they should. Any idea why? I'm using the data for the speakers provided from partsexpress.
This one: Helium - a true micromonitor -
Techtalk Speaker Building, Audio, Video Discussion Forum
I looked at the revised crossover design and tried to replicate it in Vituix and XSim, but my impedance curves does not look like they should. Any idea why? I'm using the data for the speakers provided from partsexpress.
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Ah, thank you! I'll have to get to know the applications a bit more to do the same I guess.
A bit like this look but this one isn't as it's a PR and not a woofer. Gives the general idea though.
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I'm just not sure about the highs from midrange speakers. I'll have to try it out for sure, but I think as a different project.
Not talking about a mid-range driver but a small Full-Ranger. 50 to 70mm drivers are quite capable up to 15-19kHz and you don't need to have such a HF response if you don't have matching bass response.
A 60mm FulllRanger mated with a 100mm rolled off with a small inductor about 300Hz or at the baffle step frequency
It is a single element XO in the best case scenario
Perhaps something like this tiny Visaton driver as the FullRanger
BF 32 S - 8 Ohm | Visaton
I should mention that I have received all my own small FR drivers as gifts from people with "Broken" HT in a Box speakers as most of these folks would simply rather than go out and buy a new set than repair the powered box that comes with these. I must admit that I was surprised to find they were quite capable little drivers
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