10F/8424 & RS225-8 FAST Ref Monitor - diyAudio
Go Back   Home > Forums > Loudspeakers > Full Range

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 26th April 2015, 01:35 PM   #1
xrk971 is offline xrk971  United States
diyAudio Member
 
xrk971's Avatar
 
Join Date: Oct 2012
Location: Virginia
Default 10F/8424 & RS225-8 FAST Ref Monitor

I wanted a speaker design worthy of the exceptionally high performing ScanSpeak 10F/8424 Discovery 3.5in full range driver. I decided that a short sealed Dagger TL coupled with a sealed bass unit would give me the best overall transient response and clarity. I decided to mate the 10F/8424 with the superb Dayton RS225-8 aluminum cone woofer for bass duties. The design ended up as a 24 liter volume for the woofer and a 1.1 liter 3-sided pyramid Dagger for the 10F/8424. The internal dimensions I settled on were 8in wide x 12in deep x 16in tall. The short sealed TL is made of three 6in wide x 12.5in long triangles. Construction will use 1in thick pink XPS foam and regular foam core for the short TL. The front baffle will also use a thin sub-floor plywood in order to provide adequate support for the heavy 8in driver. The design will have the option of a bass reflex vent that can be sealed for use with a Linkwitz transform, or opened up for some additional bass when group delay is not an issue. The system will use miniDSP for XO and EQ duties and bi-amped. Here are predicted results in 4pi space with baffle step and diffraction effects accounted for. XO will be at 500Hz with 4th order LR. The RS225-8 is an exceptionally flat response driver and choosing a slightly higher XO frequency will keep the distortion on the 10F very low while giving more weight to the mid bass as it comes from an 8in woofer. Calculations show that with Linkwitz transform, bass extension should be about 42Hz (f3) with max SPL around 101dB.

SPL vs freq for sealed case at 24v (no Linkwitz transform) - the hump at 2.5kHz is the baffle diffraction:

Click the image to open in full size.

Impulse response for sealed case:

Click the image to open in full size.

Group delay for sealed case is 2.5ms at 100Hz and 5ms at 50Hz:

Click the image to open in full size.

For bass reflex option, here is SPL vs freq at 24v:

Click the image to open in full size.

Here is group delay for bass reflex (2.5in dia x 11in long vent - rear firing) case, not too bad actually (about 10ms at 50Hz)

Click the image to open in full size.

Here is the Sureply thin baffle with driver holes and drivers to show basic look:

Click the image to open in full size.

Here is construction on XPS enclosure beginning:

Click the image to open in full size.

Here is the enclosure with Dagger TL internally mounted and bracing, wiring, and terminal cups installed:

Click the image to open in full size.

Currently waiting for liquid nails glue to dry...

Edit April 27, 2015: New LR2 XO @350Hz and new sound clips of many different genres. Have a listen, this speaker sounds fantastic!

10F/8424 & RS225-8 FAST Ref Monitor

Here is the new LR2 XO @350Hz:
Click the image to open in full size.

Update April 30, 2015: New Butterworth 1st order linear phase XO (BW1 XO):
Click the image to open in full size.

Phase for BW1 XO:
Click the image to open in full size.

Step Response for BW1 XO:
Click the image to open in full size.

200Hz Square Wave with BW1 XO:

Click the image to open in full size.

1.6kHz Square Wave with BW1 XO:

Click the image to open in full size.

New sound clip with 1st order BW1 XO: http://www.diyaudio.com/forums/attac...0hz-clip-b.asc

Edit May 14, 2015: Stereo Pair completed!

Click the image to open in full size.
Attached Images
File Type: png 10F8424-RS225-FAST-Freq-1m-Sealed.png (32.3 KB, 1640 views)
File Type: png 10F8424-RS225-FAST-Impulse-Sealed.png (9.9 KB, 1613 views)
File Type: png 10F8424-RS225-FAST-Group-Delay-Sealed.png (8.8 KB, 1611 views)
File Type: png 10F8424-RS225-FAST-Freq-1m-BR-xmax.png (13.6 KB, 1609 views)
File Type: png 10F8424-RS225-FAST-Group-Delay-BR.png (23.6 KB, 1614 views)
File Type: jpg 10F8424-RS225-FAST-Baffle.jpg (133.2 KB, 1623 views)
File Type: png 10F8424-RS225-FAST-Box-and-Baffle.png (409.3 KB, 1635 views)
File Type: png 10F8424-RS225-FAST-Bracing-TL.png (476.5 KB, 2019 views)

Last edited by xrk971; 14th May 2015 at 11:26 AM.
  Reply With Quote
Old 26th April 2015, 04:41 PM   #2
zman01 is offline zman01  Bangladesh
diyAudio Member
 
Join Date: Feb 2011
Location: Dhaka
Good stuff. Look forward to updates.
  Reply With Quote
Old 26th April 2015, 05:07 PM   #3
RajkoM is offline RajkoM  Bosnia and Herzegovina
diyAudio Member
 
RajkoM's Avatar
 
Join Date: Feb 2009
Very nice
  Reply With Quote
Old 26th April 2015, 08:26 PM   #4
xrk971 is offline xrk971  United States
diyAudio Member
 
xrk971's Avatar
 
Join Date: Oct 2012
Location: Virginia
Default Speaker Completed with Measurements

The glue is almost dry - could use a few days to really cure, but I was impatient and took some data anyway.

Here is the completed speaker - looks like a nice standmount studio monitor.

Click the image to open in full size.

The measurements were made with the speaker on a stand with 10F/8424 at 43in above the floor and mic at 0.5m away. This setup allows use of 4ms gate to look at above 300Hz frequency response without room reflections.

Here is the measurement showing the LR4 XO at 500Hz and the effect of applying the Linkwitz transform (a rather aggressive one to get 30Hz):

Click the image to open in full size.

Here is the harmonic distortion for no LT (very low HD over the entire range):

Click the image to open in full size.

Harmonic distortion with LT (about 1% THD at 50Hz at 82dB):

Click the image to open in full size.

Here is the Impulse response - very sharp response with no ringing:

Click the image to open in full size.

This is the high resolution detail of the frequency response with 4ms gate and 1/48th octave smoothing (this speaker has a response that is flat within about +/- 2dB. There is no EQ applied to the 10F/8424 just about -3.8dB level matching to compensate for baffle step loss of the woofer:

Click the image to open in full size.

Here is the measured group delay with the LT turned on (about 12ms at 50Hz - probably due to the very aggressive LT to hit 30Hz):

Click the image to open in full size.

How does it sound? Well you can imagine from looking at the graphs... Very very nice!

This speaker really has turned out a lot better than I anticipated given the XPS foam construction. The box resonance seems to be minimal and not contributing to the HD in substantial way. It makes the speaker extremely lightweight. I have not installed the vent yet - maybe later, but so far, the bass is quite nice and I am not missing it. The sealed alignment has very tight timing due to minimal group delay.

Here is a first sound clip - change .asc to .mp3 to listen.
Attached Images
File Type: png 10f-8424-rs225-8-fast-completed.png (369.7 KB, 2564 views)
File Type: png 10f-8424-rs225-8-fast-lt-eq-xo-no-lt.png (84.5 KB, 1666 views)
File Type: png 10f-8424-rs225-8-fast-lt-eq-hd-no-lt.png (147.6 KB, 1537 views)
File Type: png 10f-8424-rs225-8-fast-lt-eq-hd.png (152.0 KB, 1530 views)
File Type: png 10f-8424-rs225-8-fast-lt-eq-ir.png (44.4 KB, 1520 views)
File Type: png 10f-8424-rs225-8-fast-lt-eq-4ms-gate-fr.png (72.4 KB, 1872 views)
File Type: png 10f-8424-rs225-8-fast-lt-eq-gd.png (50.0 KB, 1509 views)
Attached Files
File Type: asc 10f-8424-rs225-8-fast-clip-01.asc (1.66 MB, 38 views)

Last edited by xrk971; 26th April 2015 at 08:44 PM.
  Reply With Quote
Old 26th April 2015, 08:33 PM   #5
diyAudio Member
 
5th element's Avatar
 
Join Date: Oct 2002
Location: England
You cannot go wrong with the RS225 it is an excellent driver regardless of price, the fact it's so cost effective just makes it even better.

I too have used it in a similar configuration, that being a small sealed box with an LT. It sounds wonderful like such and quite surprised me with how much bass it could put out in such a 'limited' configuration, one could say.
__________________
What the hell are you screamin' for? Every five minutes there's a bomb or somethin'! I'm leavin! bzzzz!
  Reply With Quote
Old 26th April 2015, 08:37 PM   #6
xrk971 is offline xrk971  United States
diyAudio Member
 
xrk971's Avatar
 
Join Date: Oct 2012
Location: Virginia
Quote:
Originally Posted by 5th element View Post
You cannot go wrong with the RS225 it is an excellent driver regardless of price, the fact it's so cost effective just makes it even better.

I too have used it in a similar configuration, that being a small sealed box with an LT. It sounds wonderful like such and quite surprised me with how much bass it could put out in such a 'limited' configuration, one could say.
You are right, it is a special driver regardless of price. I really like it. Can't find anything else of similar performance for even 3x the price.
  Reply With Quote
Old 26th April 2015, 09:02 PM   #7
freddi is offline freddi  United States
diyAudio Member
 
freddi's Avatar
 
Join Date: Aug 2005
Great project ! - - do you think a lower priced version would greatly suffer? - say Silver Flute woofer and PA130? (or trusty Vifa TC9) - how rigid will be that lamination when dry?
  Reply With Quote
Old 26th April 2015, 09:58 PM   #8
xrk971 is offline xrk971  United States
diyAudio Member
 
xrk971's Avatar
 
Join Date: Oct 2012
Location: Virginia
Silver Flute and TC9FD can work well too - not as refined as this setup though. I don't think I have ever had a speaker that was this flat in response without EQ.
  Reply With Quote
Old 26th April 2015, 10:32 PM   #9
BYRTT is online now BYRTT  Denmark
diyAudio Member
 
Join Date: Dec 2009
Quote:
Originally Posted by xrk971 View Post
.....I don't think I have ever had a speaker that was this flat in response without EQ.
Beautiful data so far with what seems as excellent drivers. Sound clip sounds great but guess with little more time to tweak last bit you release new ones. Very inspiring thanks share build ...
  Reply With Quote
Old 26th April 2015, 10:50 PM   #10
BYRTT is online now BYRTT  Denmark
diyAudio Member
 
Join Date: Dec 2009
Think can be educating and interesting see graphical how 2. order acoustic high pass filter for box and a Linkwitz transform performs therefor attach some data below.
With a wire i loop back my sound card and in REW set "JRiver MC 20 virtual sound card device" as output device, this way JRiver DSP engine sets inside the loop and in REW settings in DSP filters will be measured real time. Data used for filters shown down below plot area in REW and in the screen copy of DSP engine.
Attached Images
File Type: png DSP.PNG (40.5 KB, 96 views)
File Type: png GD.png (58.7 KB, 101 views)
File Type: png FR.png (55.2 KB, 89 views)

Last edited by BYRTT; 26th April 2015 at 10:59 PM.
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Scan-Speak Discovery 10F/4424G / 10F/8424G BHTX Full Range 10 27th April 2015 08:52 PM
The Nautaloss Ref Monitor xrk971 Full Range 640 12th February 2015 09:38 PM
Dayton RS225-4 & Peerless SLS 8 in woofers, Linaeum, Coaxial omarmipi Swap Meet 9 28th November 2006 04:10 PM
T-Line for Dayton Ref 8" (RS225) dunderchief Multi-Way 20 7th November 2006 07:31 AM
FS: Aurum Cantus G2si Ribbon tweeter (pair) *used* & Dayton 5" ref midwoofer mmdb Swap Meet 1 29th April 2005 08:32 PM


New To Site? Need Help?

All times are GMT. The time now is 05:40 AM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2015 DragonByte Technologies Ltd.
Copyright 1999-2015 diyAudio

Content Relevant URLs by vBSEO 3.3.2