Go Back   Home > Forums > >
Home Forums Rules Articles diyAudio Store Blogs Gallery Wiki Register Donations FAQ Calendar Search Today's Posts Mark Forums Read

Multi-Way Conventional loudspeakers with crossovers

3"-75mm-apex diameter wave guide for SS 10FF
3"-75mm-apex diameter wave guide for SS 10FF
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 23rd May 2020, 05:22 AM   #31
AllenB is offline AllenB  Australia
diyAudio Moderator
 
AllenB's Avatar
 
Join Date: Oct 2008
3"-75mm-apex diameter wave guide for SS 10FF
No, I mean the waveguide offers a narrower directivity at its lower frequencies compared to a Salmon family of the same throat, length and mouth. These will go wide at a higher frequency.

On the other hand you have an increase in efficiency through loading. I can't say I'm sure how your dome responds to this. Some drivers are better for loading, and other drivers don't respond positively enough to horn loading.

I have used a waveguide of 20" on a tweeter. It was good to 700Hz, maybe 500Hz.
  Reply With Quote
Old 23rd May 2020, 11:34 AM   #32
diyiggy is offline diyiggy
diyAudio Member
 
diyiggy's Avatar
 
Join Date: Jan 2019
Got It, thanks. Very good news for me if you go as low as 500/700 cycles with a WG and just a little dome. Hum, perhaps not too much expensive to try a 20" Seos but cut the throat to 2.5 " to 3" with a saw and glue a wood adaptator with Joseph Crow eleptical shape to fire some measurments...That what I asking myself with horns, can we barely predict a spl curve from T&S of the driver with softs like Akabak or hornresp...
  Reply With Quote
Old 23rd May 2020, 12:02 PM   #33
AllenB is offline AllenB  Australia
diyAudio Moderator
 
AllenB's Avatar
 
Join Date: Oct 2008
3"-75mm-apex diameter wave guide for SS 10FF
Sorry, I forgot to mention I use compression tweeters.

However, these aren't supposed to go this low either. It is the waveguide I'm reporting on as far as size and frequency. You can use this as a baseline and scale to what you need. Also if you have extra size available you can use it as a roundover. If you round too early you will take it wider, but smoothly.
  Reply With Quote
Old 23rd May 2020, 05:38 PM   #34
diyiggy is offline diyiggy
diyAudio Member
 
diyiggy's Avatar
 
Join Date: Jan 2019
What is the horn/WG you talk about in your last post please ?
  Reply With Quote
Old 23rd May 2020, 09:50 PM   #35
Joseph Crowe is offline Joseph Crowe  Canada
diyAudio Member
 
Join Date: Mar 2012
Location: Picton Ontario
General rule of thumb is 1/4 wavelength on the depth of the horn determines the cutoff frequency (Fc). Second to that is the mouth area must be sufficiently large to not introduce first order reflections back down the horn. But generally if your horn width is twice the depth or larger then your doing okay. This creates at least a 90 degree coverage pattern just by simple geometry. The actual crossover point depends on too many variables to discuss here and typically requires building the horn and doing a full set of measurements to see where things are at. The most important for low reflections is the horn mouth treatment in terms of the geometry at the horn mouth. Any physical abrupt edges at the horn mouth will introduce reflections and so every effort should be made to round off the horn mouth if sound quality is a priority. I mention this because itís often dismissed as not important enough to invest in further build effort.
But generally any abruptness in the entire horn flare geometry is a bad thing.
Also, the 10F on a front horn (200Hz Fc) is one of the best midrange Iíve heard.
Regarding headroom and distortion I personally target +10dB SPL above maximum listening level with <0.50% THD. If <0.20% your doing good. I do all %THD measurements at 1 meter mic distance using ARTA sine sweep. Many argue the audibility of distortion however all the tests Iíve seen to validate perceptibility were conducted on non horn speakers with >0.50% THD to begin with so Iím not sure how those tests are valid.
__________________
Joseph Crowe DIY on Instagram
  Reply With Quote
Old Yesterday, 12:16 AM   #36
AllenB is offline AllenB  Australia
diyAudio Moderator
 
AllenB's Avatar
 
Join Date: Oct 2008
3&quot;-75mm-apex diameter wave guide for SS 10FF
Quote:
Originally Posted by diyiggy View Post
What is the horn/WG you talk about in your last post please ?
DIY round OS.
  Reply With Quote
Old Yesterday, 01:20 PM   #37
diyiggy is offline diyiggy
diyAudio Member
 
diyiggy's Avatar
 
Join Date: Jan 2019
Cool I'm planing & sketching without knowledge

Thank you gentlemen. I'm going to start from your shared experience & knowledge.

It is very less simple I firstly surmised as a pandemic covid-19 lockdown project and that's good because the brain is more busy and focused than imagined : cool ... I wanted it cheap project because my wallet, not saying my manual skills, with a cheap horn of shelves I could eventually cut and adapt the throat with a little wood... It does not exist really, so let's start from DIY the horn as a first step. By beginning the hardest project part, one has a go no-go for the further steps.

So this Scan-Speak 10F 8424G00 8 ohms is around 87 db @2.83 V will ne horned. I listened the old Xrk971 recordings in home room of the 3" competitors he provided in a thread of the Full range section of the forum. I found this one to be the most neutral of all in the recording configuration : picture of the room as above from Xrk971 showed relativly reverberant condition so not so damped. I eventually disagree the paper contender is more natural. Smoother perhaps, so lightly colored, so unatural to me !


The Scan Speak for my tastes on my main speaker and with a headphone was clear, have light and very informative without brighness, the best highs of the bench especially on piano and brass, very neutral/uncolored. As a shortcut I would say the recording sounded like an unit between a very good paper and an aluminium driver without the colored smoothness of some old unit made of polymer cone as this unit is made of. I have to remember of this when

I will choose the driver below... 40 hz F3 in mind till the XO planed for the moment at 750/800 hz cause H3 are a little too high below... but measurments are with raw driver. A little too high frequency for a 15", but I dunno for the moment: horn directivity in the low, bafle step, room modes, center to center, acoustic centers of the horn for time alignment... mdern drivers that beam less fastly...then maybe futur active system with EQ are few of the datas to keep in mind. I decided to start from the horn

The room in which the speaker could be happy has an average temperature of 23įC / 73į F so the speed of sound to calculate the wave length is 343 m/s.
For a 750/800 hz XO the wawe length is 46/43 cm, so is the width of the horn mouth. I know nothing about horns, I imagine the smooth suround edge of the horn is inside that width or at least at the apex of the smooth edge transition between the external of the horn. Which is the midle of the edge, like the midle of a ruber M roll surround for ilustration. So let's take 48/45 cm bafle width for the whole speaker, it lets 2cm of smooth round transition to avoid the difraction with the 3 external sides of the horn : left & right side & top, below is the woofer unit. Earl Gedles 2 way speakers are inspiring as the last diy designs shown by experienced members like Joseph Crow, Bmc0, mabat, docali. The Qts of the ScanSpeak is limit high to be horned with 0.4 measured by some, but proves of concept exist with aready existing speaker from Joseph Crow horn to Xrk971 foam horn at diferent complexity scales.

Last edited by diyiggy; Yesterday at 01:27 PM.
  Reply With Quote
Old Yesterday, 02:50 PM   #38
diyiggy is offline diyiggy
diyAudio Member
 
diyiggy's Avatar
 
Join Date: Jan 2019
Default journal of hifi dumie planing his loudspeaker

I don't want a one meter wok horn like AvantGarde speakers that use domed drivers for their huge midrange horns with some models. Too much intrusive for a non dedicated listened room. When I look at it, I imagining street food indonesian nasi goreng cooked on such horn wok with strong fire... don't get me wrong, I do like nasi goreng tasty rice receips minute food street...

So 45 cm bafle & horn width is already a trade off. Calapamos loudspeaker size from HumbleHomeMadeHifi or The Troel's Gravsen's The Loudspeaker come in mind !

Depth of the horn to load and have a spl boost from the Xoed driver frequency: 1/4 of 45 cm, circa 18" ...drums roll.. is 11 cm circa 4.5"

Well I don't know the width of a 15" mouth bass driver which I could plan. But if the acoustic center is near the horn acoustic center.. it could provide a sort of circa time alignment if no electronic delay aka passive filter !

That's in the horizontal plan... In the vertical plan, center to center distance between the horn and the driver below must be important as well to plan the frequency acoustic XO of the loudpeaker from the very few I know about my readings at diyaudio and few loudspeakers understanding books for Dumies I have.

Ah... then comes the understanding of the acoustic Fc of the horn in its low end vs the crossover Fc of the loudspeaker crossover XO. Often, we read in the litterature and horn datasheet the horn has its own Fc and the usable range is above. I understand the usable starting range as the area where the horn still load-spl renforce, still has directivity controll : the relation between loading and directivity being a mystery to me.

If such sized horn for the Scan Speak 10F 8424G00 is enough to a beter efficienty to reach 115 db dynamic instant peaks at 1 meter below the Xmax for very limited distorsion, it's enough for my home needs. But 115 db will be funier at 3 meters listening position.

I opened an online calculator and two more meters gives a -9.5 db atenuation. So circa 125 db efficienty at 1 meter could be a targett as well to reach the 115 db max at 3 m listening position. But again I imagine it's rare in the recordings. Loudness war, use of Red book reccording in my library, limits of amp, damping numbers, Watts needed at maximun spl peaks and DAC I have... how to choose the max spl speaker number ? Ok the good efficienty of a horn married with a PA driver may help me ! But efficienty with bass driver in the PA world is meaning huge cabiners cause the VAS of such drivers is very bigger than Hifi market ones. We are often above 120 liters for a vented PA 15" around 40 hz F3 for the best.

Last edited by diyiggy; Yesterday at 03:17 PM.
  Reply With Quote
Old Yesterday, 03:17 PM   #39
diyiggy is offline diyiggy
diyAudio Member
 
diyiggy's Avatar
 
Join Date: Jan 2019
I'm mainly listen to Jazz, rock, classic and traditional/world music. Used to listen live music, mainly jazz clubs, but also big classical venues with classic. I like the live street and traditional unpluged music with few instruments. I note a trumpett has 112 db max spl at its mouth if I remember. I also note indian rythmik tablas I like too are hard tempo to reproduce because fastness and instant damping when striked and complex sound when rubbed to produce a low frequency long note. Transcient feeling also has to see with the health of the horned driver to deliver harmonics I also noted.

Hum... F3 of the speaker and alignment is a complex trade off for dumie I am. I have sealed speakers and like their clean transcient behavior. But those are classic 3 W speakers. I really don't know about a high eficienty vented 2 ways but rare listenings at enthusiasts places and reccording studios or electrised theater small venues!

At equal volume, a sealed with such 15" PA driver is more towards 70/80 hz F3 with the best for low end alignment which is Qtc (box+driver) 0.707 number.

... no subs wanted it's a 2 ways projects. Less young than younger, I may have problems of all sort to integrate and move 250 liters sealed cabinet for a clean, clear sealed design (sealed coffins are said to sound more transparant, clear near an infinite volume loads so near their VAS. I noted in my memory, less back energy from the compressed air volume equal better sound in sealed box design. I dunno but expensive 15" drivers if less than 100 liters sealed exists for a 40 hz F3 with a 0.707 Qtc, which is acceptable transcient... not a 0.5 Qtc... but with such wave length : 8.6 meters at 40 hz, I think the room and reflection are more of a problem anyway. that's my fault I should just purchase a good headphone !


So room modes, Helmotz room frequency often starting towards 200 hz in home rooms is something I have to remeber as well when will come the time to the driver/box choices... The room tules them all ! Not easy without electronic EQ... Electronic EQ is not easy because it's expensive for a good result, let's throw away MiniDSP cheapest units for instance ! Sources are of a Huuuuge importance to reproduce music.


Time now to RTFM to horn sketch. Cool pictures from 3D printed horns and the fact you can rent such printers for a day are avocating to unproscatinate... approximatly. I have a cool list : Mabat, Akabak, Hornresp listenings...

Last edited by diyiggy; Yesterday at 03:23 PM.
  Reply With Quote
Old Yesterday, 04:23 PM   #40
Joseph Crowe is offline Joseph Crowe  Canada
diyAudio Member
 
Join Date: Mar 2012
Location: Picton Ontario
The Eton Orchestra 12-612 achieves 32Hz F3 with 93dB sensitivity in a 100 litre enclosure. I think this strikes a very reasonable size compromise and hits 112dB with a single cabinet at 1 meter. Their appearance exudes quality as well.
Iím thinking 750hz would be the upper limit which is an octave below any kind of breakup.
__________________
Joseph Crowe DIY on Instagram
  Reply With Quote

Reply


3&quot;-75mm-apex diameter wave guide for SS 10FFHide 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

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
6.5" Wave guide Trev98 Multi-Way 5 7th May 2019 04:05 PM
Changing bass reflex port diameter from 80mm to 75mm Niels K PA Systems 14 28th July 2016 12:18 PM
Ok, I get it. A wave guide is not a horn. peteleoni Multi-Way 17 8th September 2013 06:22 PM
what is a wave guide? Joules Multi-Way 7 12th May 2005 02:25 PM
APEX Chip Cross-Ref Guide speaker Chip Amps 0 4th April 2004 03:02 AM


New To Site? Need Help?

All times are GMT. The time now is 01:50 PM.


Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2020 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 14.29%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2020 DragonByte Technologies Ltd.
Copyright ©1999-2020 diyAudio
Wiki