Loudspeaker Design

5/26/2018 Loudspeaker Design

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Loudspeaker DesignDesigning The Monochromes

By: Beau Seigfreid


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As I went down the list of drivers on the list, I also put the drivers through modeling on

WinSpeakerz to see just how they would react to the vented enclosure. The majority of

the woofers had a very similar response to the enclosure. The woofers frequency

response charts are as follows;

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Woofers Price F3 dB Sensitivity

1. Dayton Audio RS225-8 8" ReferenceWoofer

$57.42 28 Hz 86 dB

2. Dayton Audio DC160-8 6-1/2" ClassicWoofer

$21.78 34 Hz 88 dB

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I; Dayton Audio ST210-8 8" Series IIWoofer

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Figure 4.1 Woofer Selections

Dayton Audio RS225-8 8" Reference Woofer This speakers frequency plot can be

found on the next. I really wanted an 8 woofer to go with a set of tweeters because I

really wanted that bass response in my set of drivers. I love the response ability of these

speakers but they have some significant problems before 1 kHz with a very steep roll-off.


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Figure 4.2 - Dayton Audio RS225-8 8" Reference Woofer

The next drivers I chose were from Dayton Audio just like all the other drivers in this

paper will be. This woofer is the Dayton Audio DC160-8 6-1/2" Classic Woofer. I

wanted to push myself to stick with a particular brand of speaker in order to build loud


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speakers that had drivers that were meant for each other, so to speak. This speaker is

smaller than the speaker I intended to have.

Figure 4.3 - Dayton Audio DC160-8 6-1/2" Classic Woofer


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The speakers I got really excited to get my hands on were the Dayton Audio ST210-8 8"

Series II Woofers. Amazingly, these ones also have the dip similar to the first 8.

Figure 4.4 - Dayton Audio ST210-8 8" Series II Woofers


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After all the debate, I decided to go with the next set of drivers which are the Dayton

Audio DS215-8 8" Designer Series Woofer Speaker. The frequency response plot looks a

bit easier to work with when it comes to a cross-over at about 1800 Hz. The f3 of the

driver is fairly impressive as well at 36 Hz.

Figure 4.5 - Dayton Audio DS215-8 8" Designer Series Woofer Speaker


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Figure 4.6 A Modeled Dayton Audio DS175-8 6 1/2" Designer Series Woofer Speaker

That driver looks like this when modeled in a 18 x 14 x 14 (H x W x D) enclosurewith a 1.5 inch diameter/ 2.18 circular vent. The bass boost is what I want in order toachieve a big, warm sound. And by dropping the diameter of the speaker from 8 to 6 -1/2, the price dropped along with the sensitivity. This ended up with my woofer andtweeter both having the same sensitivity.

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Tweeters Price dB Sensitivity

1. Dayton Audio ND28F-6 1-1/8"Neodymium Dome Tweeter

$23.29 88 dB

2. Dayton Audio DC28F-8 1-1/8" SilkDome Tweeter

$19.75 89 dB

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Figure 5.1 Tweeter Selections Table

I ended up narrowing down my tweeter selections to the two silk tweeters based on price

and quality. The first of the two is this tweeter, the Dayton Audio DC28F-8 1-1/8" Silk


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Dome Tweeter. The tweeter looks to have some problems as the frequencies enter the

very high ranges.

Figure 5.2 - Dayton Audio DC28F-8 1-1/8" Silk Dome Tweeter


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In the end, the response from the woofer and tweeter landed at about plus or minus 3.5

dB from 100 Hz to 10 kHz. After looking at some response charts from some KRK Rokit

6 (Which is what the box is modeled after) I saw some distinct differences in bass

extension and high extension but the response overall is not all that different without

smoothing.

This is the tweeters overall response as depicted by FuzzMeasure from around 1400 to

30 kHz.


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This is the woofers response without the tweeter being a part of the overall response.

This final graph gives the overall system response of the woofer and tweeter combined.

The f3 of the system is about 80 Hz. I think with a stronger crossover set at a higher

frequency (2000 Hz) the response will become much more clear as this response seemed

to be formed from a distorted tweeter found after presentation day. The goal was to be

able to have usable speakers at the end of the semester with the cheapest cost possible. I

originally sought out to build the speakers with only $300 and managed to save $40 of

that with this speaker design totaling out to about $260. Now with that being said, I


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expect to pay at least $60 extra on a new crossover in the future. This would total the

loudspeaker cost at around $320.


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