I arrange a simulation for the Beyma 15LX60V2. xmax 9 mm, fs 42 hertz, VAS 105, Q's 0.44. VB 95L QTC 0.71I think the side firing / opposing subs will be the easiest to narrow down and my initial gut feel is the Beyma 15 LX 60 Mk 2 https://www.beyma.com/speakers/Fich...ers-data-sheet-low-mid-frequency-15LX60V2.pdf but I am am sure there will be other good choices available and I would suggest that you can save a bit of $$ per driver here without compromising on system sound quality.
Thank you for going ahead with this, but let's not hurry on the subwoofer module which I have no idea when I can start. I don't want your effort wasted.
And I don't think I will go with 2 13"~15" woofers per side for the subwoofer module. I think that's way too much of everything including SPL for me.
122 db at 50 hertz
119 db at 40 hertz
115 db at 30 hertz
It could be a single sub but it’s still quite sub-stantial (sorry).
Maybe use dual drivers in a compound arrangement to halve the Vas and therefore halve the enclosure to 47L. It would go well as a four ohm
Load with a class D power amp.
I am digesting great suggestions on the woofer module, though I wanted to settle on the midbass first. While thinking on woofers, I want to start the midbass discussion by presenting my preliminary choice.
It is Scanspeak Illuminator 18WU/4741T. Very expensive but the FR and other specs look impressive. I am also looking at 18W/4531, and a few Satori Papyrus cone woofers, and Silver Flute wool cone woofer. The Silver Flute one shows a hard-to-believe FR plot and price, though other aspects(distortion?) are not shown or certain.
I am also surprised that famous Scanspeak ones like 8542, 8545 are not that great in FR plots, nor the Seas Excel paper-based ones...
It is Scanspeak Illuminator 18WU/4741T. Very expensive but the FR and other specs look impressive. I am also looking at 18W/4531, and a few Satori Papyrus cone woofers, and Silver Flute wool cone woofer. The Silver Flute one shows a hard-to-believe FR plot and price, though other aspects(distortion?) are not shown or certain.
I am also surprised that famous Scanspeak ones like 8542, 8545 are not that great in FR plots, nor the Seas Excel paper-based ones...
Thank you for the information, especially the criterion for a good sealed box woofer. I am a bit concerned that you don't find 8" alternatives for the woofer that meets your or well-known woofer criteria... I will try to look at options myself soon.
On the 10 inch l was looking at bass drivers. Not mid bass. These could be side mounted like the Kef Blade.
8 inch bass drivers like Volt and Acoustic Elegance are capable of real bass. Selecting the diameter is always a compromise!
Here is an interesting article for your digestion
http://www.troelsgravesen.dk/EKTA-mkII.htm
8 inch bass drivers like Volt and Acoustic Elegance are capable of real bass. Selecting the diameter is always a compromise!
Here is an interesting article for your digestion
http://www.troelsgravesen.dk/EKTA-mkII.htm
Probably nothing. Smooth. Refer to the sealed box f3.
My advice is to look 89-91 sensitivity and a 32-38 mm VC with +-4 mm or more X max.
I have attached a few similar drivers. Some have different cone materials like the 4434 version which is fibre glass. These cones tend to be stiff and light weight delivering punch and snap. Paper has a thicker sound.
Because of those subjective differences you need to carry over that into your dome mid.
I would place paper with a silk dome mid and the fibre glass with an aluminium or titanium dome mid and tweeter.
A crash snare overtones need to sound coherent and smoothly blended.
If you prefer a live sound with snap and crack, free of thickness then the later is likely your preferred choice.
But it you prefer a more forgiving, damped and thicker transient attack then the former might be your ticket .
You really can’t go with Scan.
Attachments
I don't know either the brand or it's philosophy but driver type in this system is what it 'should be' imo (if you only see the situation from direct radiating membrane area) :
2x10" ~ 1x15"
If you have to reproduce 1 octave lower then double membrane are ( so 2x15") you want to go lower an octave further down then you'll need 4x15".
You've got your 4 first octave covered that way ( allow 2 octave for the pair of 10"). Pair this with a good CD and you are done.
Vertical stacking and spaced pair help with constant vertical directivity management and help mitigating floor bounce. Separate Sub bass cab help to deal with room modal behavior ( and being vertically spaced it is a step toward multi sub approach). Low IMD in lows/low mid/high, high efficiency and huge dynamic capability if used in multiamp/dsp setting can be expected. It have the potential to produce deafning output level with low distortion.
I bet there is nice directivity behavior overall too.
Large membrane area in mid range have it's 'sound'. As there is less movement there is less distortion and for direct radiators it's nice. Dynamic is different too wrt to smaller drivers.
Sounds more natural to me.
Driver selection is the last step of a design imho. Acoustic design ( which in my view have more importance in overall result) will be compromised 'de facto' once you try to fit drivers previously selected together into one design.
Things like CTC, waveguide or drivers dimension could compromise too much the acoustic design if you try to design from driver at first.
Have you defined your target for acoustic design? ( horizontal/vertical directivity behavior and coverage, the bandpath for each way, global size and requirement for diffraction treatment or not, kind of load,....)?
I've been close to posting the same thoughts....but could see how much fun OP was having with drivers, so i kept holding off.
Glad you took the time to try to help in a kind manner
Driver selection really is one of the last steps in a good design, ime.
Well, i fully get jheoaustin is contemplating drivers but...
The real advantage we have as diy is to taylor to our needs which is really difficult for commercial brands to do.
We can refine even further to anyone likings by choosing components and suchs... but one thing is difficult to taylor and it is the room.
So by first analysis the listening situation ( which level, over how wide an area, listened below, at or above critical distance, which kind of rendering : RFZ or Early Reflections 'enhanced', room dimension and shape, are acoustic treatments possible? If yes up to which point in bulkness, etc,etc,...) it will help define key parameters of design for the acoustic design of loudspeaker.
From there you can restrain the choices to what matter to you and what can accept compromise but it's taylored to your taste.
Of course driver type and number of ways can be an important choice but it'll bring limitations during design. That's all the point to me.
The real advantage we have as diy is to taylor to our needs which is really difficult for commercial brands to do.
We can refine even further to anyone likings by choosing components and suchs... but one thing is difficult to taylor and it is the room.
So by first analysis the listening situation ( which level, over how wide an area, listened below, at or above critical distance, which kind of rendering : RFZ or Early Reflections 'enhanced', room dimension and shape, are acoustic treatments possible? If yes up to which point in bulkness, etc,etc,...) it will help define key parameters of design for the acoustic design of loudspeaker.
From there you can restrain the choices to what matter to you and what can accept compromise but it's taylored to your taste.
Of course driver type and number of ways can be an important choice but it'll bring limitations during design. That's all the point to me.
Last edited:
OK different ways to skin a cat! I tend to do both at the same time. That said I tend to collect drivers and make up set's and then try to work the goals of the overall design against a given driver set. To each their own as long as your design accomplishes your goals all is good.
Rob
I agree.
Lots of good input here.
My take is this. You really can’t compare a technically correct loudspeaker driven by objectivity to what happens in a diy loudspeaker builder space.
In a commercial design yes the acoustic design is defined so it fits with an existing product range.
Commercial loudspeaker manufacturers are driven by cost. As you go up in price the design becomes more refined and often unique like the Kef Blade for example. The designer is cut loose without constraints in such a design. Industrial designers take the acoustic design and try and make it saleable.
The importance of the baffle layout was raised early on. The benefit of adding a midrange driver and a mid bass driver are undeniable. Cylinder shapes have been mentioned.
However in the diy space often the builder doesn’t have the tools or technical insights to predict different different acoustic design.
Does a home grown diy loudspeaker turn out right the first time? Very seldom. The TO has said he plans to make it modular with cylinders. A cylinder’s acoustics are well defined. So that base is covered. Text books hint at the effect of using a cylindrical shape.
A diy builder then has to start somewhere. He doesn’t have a warehouse full the drivers to pick from.
There is strong view among successful consumers loudspeaker designers that subjectivity should lead in the actual voicing of consumer loudspeakers. Wrapping a consumer design in too many pre determined object criteria can be a mistake.
It might not look visually appealing. Or it
might miss the mark subjectively.
A consumer music lover is not a loudspeaker designer or a diy loudspeaker builder after all. Nor are they a mix engineer eyeing off the polar response charts. This project has to please his partners ears.
Harbeth for example have followed this lead for commercial success. Andrew Jones plays on this point in media interviews. If people don’t buy it what’s the point. There is always well founded engineering in a successful loudspeaker system. But typically these are not stratosphere hi end designs. They are the volume sellers.
https://www.theabsolutesound.com/articles/speaker-designer-roundtable/
The crunch is it has to sound good to the consumer in the consumers room. This is by far the most significant variable effecting the outcome because it’s so unpredictable.
The diy builder has the advantage here with flexibility to modify his creation until he is satisfied with the results.
It’s very simple. Always trust your ears before delving into the maze of science and graphs. If it sounds promising then peer into the curves.
Yes, perhaps true for many people... @krivium 's point about acoustic design first is a key point. Yes it is true that simulation of the baffle layout is a hurdle. But there are people available to help. I have found this site to be full of people who are very willing to give technical guidance, even running BEM simulations for little more than a "thank you"...
I think I might push back on that thought, just a bit. I think it is important to do some measuring to get the system close to "good". Then subjective voicing can take over. It is true that in the past, some very experienced designers could design a good speaker by ear, most of us are not so gifted.
With sophisticated measurements, the system can be tuned to be very good based on measurements alone, so that the subjective voicing involves just small tweaks.
But it is not necessary to perform a full blown CTA2034 set of FR scans to start the process. A simple on-axis scan of each driver, combined with the traditional rule of thumb guidelines, can get us close. With this starting point, the subjective voicing will take longer, but it is possible to achieve an excellent result. We may not be able to calculate the power and directivity curves for our speaker, but if we followed good design practices, we should be OK. A speaker does not have to have a perfect power & directivity response in order to sound excellent... Some may disagree with me on that...
But my point is that some basic measurements really are necessary to get us started on the path to success. A $100 USB microphone is not the ideal measurement setup, but it is two orders of magnitude better than nothing.
I absolutely agree with this. Good point.
Thank you for your reply. There are so many facets to coming up with a loudspeaker system.
Quoted from Troel’s own designs
http://www.troelsgravesen.dk/The-Loudspeaker.htm
I’ve blocked this out for clarity as there is some really valuable insights here for home diy loudspeakers from a recognised loudspeaker designer who has worked with the major driver manufacturers over many years to come up with some excellent designs.
“Every speaker construction starts with a mockup! Falling in love with bunch of drivers and assume they will make a wholesome family very often is waste of money. As can be read here, three midrange drivers had to be tried to find the best for this project. Above the midrange drivers were placed in 34 litre closed boxes and the bass driver on a simple U-shaped frame. Believe me, these bass drivers deliver deep thunderous bass even from a simple open baffle. I fact I have to fix the door fillings to my workshop as they were rattling like crazy!”
“A few comments on MEASUREMENTS before you start interpreting all the readings below.”
“First of all, if we think measurements will tell us how a speaker sounds, we're wrong. The perception of sound is way too subjective to be reflected in any measurements we can perform. A loudspeaker system is meant to give us a satisfying idea of an acoustic event and for some people a pair of 5 USD ear-plugs are enough, others spend 200 kUSD on a truly full-range pair of speakers - and the latter may not be happier than the former.”
“Measurements may give us an idea of tonal balance of a system, i.e. too much or too little energy in certain areas, although dispersion characteristics play a vital role here. A two-way 7+1 and a three-way 7+4+1 may display similar horizontal dispersion, yet sound very different. Measurements may tell us about bass extension if far-field measurements are merged with near-field measurements. In addition to this, ports may contribute to bass extension.”
“Most of we diy'ers do not have access to an anechoic room for full-range measurements from 20-20000 Hz.
What cannot be seen is what kind of bass performance we get in a given room. Bass performance is highly dependent on in-room placement of your speaker and the same speaker can be boomy in one place and lean in another. Actual SPL level at 1 meter distance and 2.8V input is useful for en estimate of system sensitivity and combined with the impedance profile may give an idea of how powerful an amplifier is needed to drive the speaker to adequate levels.”
“What measurements do not tell is the very sound of the speaker unless displaying serious linear distortion. The level of transparency, the ability to resolve micro-details, the "speed" of the bass, etc., cannot be derived from these data. Distortion measurements rarely tell much unless seriously bad, and most modern drivers display low distortion within their specified operating range.”
“Many people put way too much into these graphs and my comments here are only meant as warning against over-interpretation. There are more to good sound than what can be extracted from a few graphs. Every graph needs interpretation in terms of what it means sonically and how it impacts our choice of mating drivers, cabinet and crossover design.”
“What measurements certainly do not tell is the sonic signature of the speaker, because speaker cones made from polypropylene, aluminum, Kevlar, paper, glass fiber, carbon fiber, magnesium, ceramics or even diamonds all have their way of adding spices to the stew. Nor do measurements tell what impact the quality of the crossover components add to the sound, from state of the art components to the cheapest of coils and caps, they all measure the same if values are correct, yet sound very different.”
Quoted from Troel’s own designs
http://www.troelsgravesen.dk/The-Loudspeaker.htm
I’ve blocked this out for clarity as there is some really valuable insights here for home diy loudspeakers from a recognised loudspeaker designer who has worked with the major driver manufacturers over many years to come up with some excellent designs.
“Every speaker construction starts with a mockup! Falling in love with bunch of drivers and assume they will make a wholesome family very often is waste of money. As can be read here, three midrange drivers had to be tried to find the best for this project. Above the midrange drivers were placed in 34 litre closed boxes and the bass driver on a simple U-shaped frame. Believe me, these bass drivers deliver deep thunderous bass even from a simple open baffle. I fact I have to fix the door fillings to my workshop as they were rattling like crazy!”
“A few comments on MEASUREMENTS before you start interpreting all the readings below.”
“First of all, if we think measurements will tell us how a speaker sounds, we're wrong. The perception of sound is way too subjective to be reflected in any measurements we can perform. A loudspeaker system is meant to give us a satisfying idea of an acoustic event and for some people a pair of 5 USD ear-plugs are enough, others spend 200 kUSD on a truly full-range pair of speakers - and the latter may not be happier than the former.”
“Measurements may give us an idea of tonal balance of a system, i.e. too much or too little energy in certain areas, although dispersion characteristics play a vital role here. A two-way 7+1 and a three-way 7+4+1 may display similar horizontal dispersion, yet sound very different. Measurements may tell us about bass extension if far-field measurements are merged with near-field measurements. In addition to this, ports may contribute to bass extension.”
“Most of we diy'ers do not have access to an anechoic room for full-range measurements from 20-20000 Hz.
What cannot be seen is what kind of bass performance we get in a given room. Bass performance is highly dependent on in-room placement of your speaker and the same speaker can be boomy in one place and lean in another. Actual SPL level at 1 meter distance and 2.8V input is useful for en estimate of system sensitivity and combined with the impedance profile may give an idea of how powerful an amplifier is needed to drive the speaker to adequate levels.”
“What measurements do not tell is the very sound of the speaker unless displaying serious linear distortion. The level of transparency, the ability to resolve micro-details, the "speed" of the bass, etc., cannot be derived from these data. Distortion measurements rarely tell much unless seriously bad, and most modern drivers display low distortion within their specified operating range.”
“Many people put way too much into these graphs and my comments here are only meant as warning against over-interpretation. There are more to good sound than what can be extracted from a few graphs. Every graph needs interpretation in terms of what it means sonically and how it impacts our choice of mating drivers, cabinet and crossover design.”
“What measurements certainly do not tell is the sonic signature of the speaker, because speaker cones made from polypropylene, aluminum, Kevlar, paper, glass fiber, carbon fiber, magnesium, ceramics or even diamonds all have their way of adding spices to the stew. Nor do measurements tell what impact the quality of the crossover components add to the sound, from state of the art components to the cheapest of coils and caps, they all measure the same if values are correct, yet sound very different.”
This was an oft expressed point of view in the days before polar measurements were more popular.
Now I'm not saying that polar measurements don't require in depth interpretation, but when people see a good looking response plot these days they more often say that's nice, but what does it mean?
Similar could be said about listening tests for driver tonal characteristics. We've learned to control some aspects of this and to create the sound we are looking for, when appropriate choices have been made in other areas.
The caveat here is that these days as
To be honest l did this on my last reincarnation and love what it’s done to my listening pleasure. But l barely talk about it though in The Church Sunday School because people only want to take the easy path.
I also believe many under rate the significance or impact of their rooms acoustics preferring to believe that those perfect off axis curves of plots they froth over on a Klippel scanner are the cure all miracle.
But how does this apply to your room?
This is where a complete understanding is important. Because without determining the technical issues like the critical distance and absorption coefficient of the room then the dispersion angle and ratio of direct and indirect sound could be wrong.
REW used correctly is your friend.
This is now almost routine for home studio owners using sub $2000 near monitors with Sonar Works. Yet we audiophiles on a shoe string budget keep looking through the wrong end of the telephone….so to speak.
I agree (totally).
To be honest l did this on my last reincarnation and love what it’s done to my listening pleasure. But l barely talk about it though in The Church Sunday School because people only want to take the easy path.
I also believe many under rate the significance or impact of their rooms acoustics preferring to believe that those perfect off axis curves of plots they froth over on a Klippel scanner are the cure all miracle.
But how does this apply to your room?
This is where a complete understanding is important. Because without determining the technical issues like the critical distance and absorption coefficient of the room then the dispersion angle and ratio of direct and indirect sound could be wrong.
REW used correctly is your friend.
This is now almost routine for home studio owners using sub $2000 near monitors with Sonar Works. Yet we audiophiles on a shoe string budget keep looking through the wrong end of the telephone….so to speak.
Last edited: