Relative Size of Drivers = how many of these to equal one of those?

BlueWizard

Distinguished Member
Let's go back to the beginning where the 'controversy' started. This is the question that was asked --

"So in a ideal world but only for performance sakes not aesthetically with a blank sheet what sort of speaker design would you have built money no object to cover the audio spectrum 20-20khz and why ie size drivers, number off ?"

Notice he says SPEAKER DESIGN, not music system. Though I didn't answer precisely in the context of his question of blank sheet implied unlimited funds. I still stand by my answer in the context of the broader discussion, and in the context of this specific question.

My response -

"20hz is something of a piped dream, as much as some people see it as a goal, it is not really necessary for music, and though nice for movies, equally not really necessary."


Now I have to admit that in the context of unlimited fund and unlimited technical expertise, I did not answer his question. But, there is virtually no one with unlimited funds and unlimited technical expertise. Even speaker manufacturers do not have unlimited resources.

However, there are speaker designs, not music systems, that can come close to the ideal, but it is going to be extremely difficult and extremely expensive to achieve.

If you really want full range in a speaker design, you need to take an approach similar to this -

Specification of F1.1A_HiVi,Inc.

But notice, that the specs on this design do not achieve the stated goal. I'm simply illustrating how massive you have to get to come close. Actually if we assume it is 35hz at -3db, then likely the -6db is going to be just sub-30hz.

Really, it can't be done without a Subwoofer in any practical sense. But if we include a subwoofer, we are not talking about a Speaker Design, we are talking about a complete and complex system.

As I said before, you will not get the seamless integration of Subwoofer without Electronic Bass Management for BOTH the Front and Sub. That can be done for Stereo, as I have already pointed out, and it can be done for home theater as virtually every AV Receiver from the cheapest to the most expensive has Electronic Bass Management.

But again, if we include the Sub, we are no longer talking about a Speaker Design, we are talking about System Design. In the context of the original question, there are few to none practical Speaker Designs that can meet the goal of 20hz on the low end. And, there is very little to no content down that low in music. Yes ...already acknowledge... that there is some music somewhere that has this deep content, but I would say a vast majority of people will never encounter it.

In a Speaker Design, which is the context of the original question, it is extremely difficult to go much below 30hz, and if you set sub-30hz as a goal, count on the price getting very very high.

The problem is, you simply ignored the context of the original question and of the original discussion, and went off on your own unrelated tangent.

I can see your point, but your point is outside the context of the discussion. You can't see my point because you seem to be refusing to see the context ... despite the fact that I have explained it several times.

The original question that started this side thread dealt with a SPEAKER, not a SYSTEM. That is the context in which I answered. Until you can see that context, there can be no productive discussion. In the context of a SYSTEM, I certainly do see your point, but the data I provided, and the question that was asked and answered in not in the context of a full system - stereo or surround sound.

There are circumstance where I would have a Subwoofer. But they are for an expensive Stereo system with bass management, or in an elaborate and expensive Home Theater system. Since I do not have the funds for either of those, I choose to concentrate my money where it will do the most good, and that is on a good pair of Stereo Floorstanding speakers. In that context, you will struggle to go Sub-30hz. Though my speakers are rated at 28hz at -6dB. To go much below that in this context, gets expensive and impractical.

Now I said earlier, that until you can see the context, there can be no productive discussion. That's not totally true; between us there can be no productive discussion. However, I think everything you said and everything that was discussed, was productive to the casual reader following this thread. In that sense it was generally productive, but it was unresponsive to the comments I made.

Context is everything.

Steve/bluewizard
 
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MemX

Well-known Member
Nice links and research in that post, @mattkhan, I haven't seen those before! :thumbsup:

Could be worth a post on DB as a 'I was reading the other day...' sort of thread? :)
 

BlueWizard

Distinguished Member
Actually, I did find one speaker, though I'm sure there are a few more, that goes well under Sub-30hz. In this case, 22hz, but you better plan on winning the lottery if you are going to have these speakers -

Specification of 2.5F_HiVi,Inc.

1x15" woofers which can't be seen, 4x5" mid-bass, 16xTweeters, 16xRibbon Super-Tweeters.

Steve/bluewizard
 

mattkhan

Distinguished Member
@BlueWizard as I said, a speaker is a system in itself. A passive speaker is a collection of drivers connected by passive crossover(s) and, if well designed, arranged in such a way as to produce a time and/or phase coherent reproduction of the signal across the operating bandwidth. There is absolutely no difference, conceptually, here to a system that uses 1 or more physically distinct subwoofers to deal with the lowest octaves.

The fact that you choose to limit the scope of your reply to a particular physical design is simply your choice. Modern technology is not imposing that constraint and it does not require unlimited funds, or even a particularly large amount of funds, to go down that road.
 

MIKEVO

Well-known Member
Well, I was lucky as I worked for Kef at the time and could buy them at staff price for £700.
I think the RRP was about £2000.

Kef were great in those days, they had loads of HiFi enthusiasts working for them and as such allowed us to buy products at greatly reduced prices.

By the way, the Kef 104/2 with the Kef Kube was also able to get to about 20hz, they were about half the price of the 107.
 

MemX

Well-known Member
"So in a ideal world but only for performance sakes not aesthetically with a blank sheet what sort of speaker design would you have built money no object to cover the audio spectrum 20-20khz and why ie size drivers, number off ?"

My response -
"20hz is something of a piped dream, as much as some people see it as a goal, it is not really necessary for music, and though nice for movies, equally not really necessary."

However, there are speaker designs, not music systems, that can come close to the ideal, but it is going to be extremely difficult and extremely expensive to achieve.

If you really want full range in a speaker design, you need to take an approach similar to this -

Specification of F1.1A_HiVi,Inc.

But notice, that the specs on this design do not achieve the stated goal. I'm simply illustrating how massive you have to get to come close.

Really, it can't be done without a Subwoofer in any practical sense. But if we include a subwoofer, we are not talking about a Speaker Design, we are talking about a complete and complex system.

As I said before, you will not get the seamless integration of Subwoofer without Electronic Bass Management for BOTH the Front and Sub. That can be done for Stereo, as I have already pointed out, and it can be done for home theater as virtually every AV Receiver from the cheapest to the most expensive has Electronic Bass Management.

But again, if we include the Sub, we are no longer talking about a Speaker Design, we are talking about System Design. In the context of the original question, there are few to none practical Speaker Designs that can meet the goal of 20hz on the low end. And, there is very little to no content down that low in music. Yes ...already acknowledge... that there is some music somewhere that has this deep content, but I would say a vast majority of people will never encounter it.

In a Speaker Design, which is the context of the original question, it is extremely difficult to go much below 30hz, and if you set sub-30hz as a goal, count on the price getting very very high.

There are circumstance where I would have a Subwoofer. But they are for an expensive Stereo system with bass management, or in an elaborate and expensive Home Theater system.
I am a little confused...

You are saying that a subwoofer is hard to integrate and requires expensive electronic equipment. May I ask at what point a subwoofer becomes a subwoofer and not just part of a speaker?

For example, if I put my two subwoofer boxes each side of the TV and then placed my L and R speakers on top of them, would that effectively be a speaker?
Does moving a subwoofer into a better location (aesthetically or accoustically) and leaving the speakers where they are transform it into a sub+satellite system?

If it's simply a case of locating all speakers in the same place (subwoofer, woofer, mid, tweet, super-tweet, etc) and a blank-sheet, size and cost-no-object specification has been put on the table, as per the OP, why not design a full range speaker that is properly full-range? I don't think it need be overly difficult.

For example, my subwoofers are 36" wide by 33.5" tall by 20" deep. If I turned them sideways the width would only be 20" at the front, only 5" wider than your proposed designs on the previous page. On top of that I could then build whatever I wanted to with regards to mids/tweets, depending on what crossover I wanted to run. Passive crossovers could be added into the cabinet during the build for the mids/tweets (which I presume is the usual practice?) as could plate amps (or even rack amps, depending on overall design) for the power required for the subwoofers. Then you'd just need a power connection and the audio input In socket.

Or am I missing things and that is too simplistic? :eek:
 
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MemX

Well-known Member
I am not sure posters there need persuading of the merits of low frequencies :laugh:
lol :laugh:

Fair point ;)

I still think the graphs are interesting, though, I've not seen them referenced before!
 

Matyam

Active Member
E-SEVEN-15 (E715) or did you mean the E315? I downloaded the "E" series brochure, and didn't see an 715 model. The top was the E315 in a 3-way configuration with a single 15" woofer.

The E315 is 102db Sensitivity, 400w, 28hz to 20khz (unqualified).

It is one thing to say you have 20hz response in your room, but for that to mean anything we would need to know how you measured that.

The true test is to normalize the volume at 1khz, then sweep down as see how loud 20hz is in your room. I'm guessing, not as loud as you would think.

I have some speakers that are rated at 80hz on the low end (cheap bookshelf), but I can hear 30hz very nicely from them ...IF... I turn the volume up, but that is cheating. The question is how much low end can you hear if you play a 1khz tone and set the volume to a comfortable workable level, then sweep up and down the frequency range. I think on both ends it is not likely to be a loud as you implied.

However, you are right in-room response boosts the bass, so perhaps you are getting decent sound at 20hz, but I would like to see it measured along side the same volume setting at 1khz.

Still, sweet powerful speakers. I sure you enjoy some great movie watching experiences with that system. I suspect it brings both the Thunder and the Light.

Steve/bluewizard
Yes steve E 715s black coffins
 
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BlueWizard

Distinguished Member
I am a little confused...

You are saying that a subwoofer is hard to integrate and requires expensive electronic equipment. May I ask at what point a subwoofer becomes a subwoofer and not just part of a speaker?

For example, if I put my two subwoofer boxes each side of the TV and then placed my L and R speakers on top of them, would that effectively be a speaker?
...

Or am I missing things and that is too simplistic? :eek:

Do you have an AV Receiver? If so, then you have Electronic Bass Management.

Steve/bluewizard
 

MemX

Well-known Member
I do - Onkyo 818 with Audyssey XT32.

It wasn't overly expensive, though, I thought £600 brand new was excellent value for the EQ solution it provides. Certainly better value than some of the more esoteric 'solutions' for 'improved' sound quality that I've seen mentioned online, or even some of the more commonly used technology!

I think that issues with integrating subwoofer-band bass wil!l come about regardless of a full-range floorstanding speaker or sub+sat setup, simply due to the effects of a given room's dimensions and 'leakiness' on room gain and room modes, so in that manner either option will be require a similar amount of work to integrate successfully.

To my mind that means that either option is a valid solution and it is down to personal choice - my own preference would be sub(s)+sat as it avoids monolithically large floorstanders while also allowing placement of the subwoofer(s) in the best position (for output and/or smoothing of room modes) to be determined using programs such REW and/or by doing the good ol' sub crawl, and if you take the Geddes approach of multiple smaller subs in the corners or midway along each wall, the subs can be discreet yet have excellent output and a smooth response curve with minimal EQ needed, as I understand it.

Of course, your placement options can be restricted by 'WAF' ;) but then I would have thought it still provides more options for placement that provides a good in-room response than the only two locations a L and R set of floorstanders can go, so it's still compromises in effect, just different ones! :laugh:
 

mattkhan

Distinguished Member
Cheapest way to integrate a sub is a miniDSP., maybe £100 delivered. Another way is to do it all on a computer (especially if that is your source anyway). There are more expensive options of course.
 

BlueWizard

Distinguished Member
Two aspects were involved in the original question, which I previously quoted.

1.) Anything goes
2.) A Project

1.) Anything goes - I rejected that as a pointless discussion, even the most advanced design labs do not have infinite resources, infinite money, infinite technical expertise, and (metaphorically) an infinite place to put it all.

2.) A project - Which to me implied he was intending to build a DIY speaker - Speaker Design Project. Which is one of many reasons why I rejected premise number 1.

I responded to a clear context, though I may have inferred that context, it none the less framed my response.

Chasing Sub-30hz in the context is a piped dream, as you will find if you look at the low end response of a vast majority of stand alone speakers out there. So, there is a large context, which is my introducing a means by which people can find speaker driver equivalents, as in one 6.5" equal two 5" drivers. That sets the overall tone of Drivers and Stand Alone full-range speaker. The second context was the specific question asked. He did not say - Help me design a System that can achieve 20hz response? Others cover that unrelated topic. What is did say was - Help me with a SPEAKER DESIGN PROJECT? Both those contexts frame and continue to frame my response.

I responded with a very realistic speaker design, that a DIY builder could potentially afford, and with few technical complications beyond those found in any basic speaker design/built.

Yes, a compilation of drivers in a box does constitutes a speaker system, but when you add a Subwoofer, the system and the associated electronics become substantially more complicated, and especially so when you ignore the context of the original question.

I never claimed that multi-speaker AV systems and even multi-speaker stereo systems could never reach in the vicinity of 20hz. What I said repeatedly, ...repeatedly..., in the context of the original question, was that in a single cabinet full-range speaker, as would be associated with a Speaker Design Project, significant Sub-30hz response was difficult and expensive. I've seen nothing that has been said so far that contradicts that statement in the context it was made.

I've never said that Subwoofers don't do what Subwoofers clearly do. I never said that those with many thousands to spend could not come close to achieving Sub-30hz response. In fact, I gave examples of individual speakers that did just that.

What other think they thought I said, is irrelevant, I responded to a question with my best and reasonable interpretation of the context, and as I have said, nothing has been said to sway me from that opinion. The fact that other choose to ignore the clear context, and the fact that other choose to replace what I said, with what they wanted to hear, is not in my control.

In the context of the question asked, I stand by my answer. I also notice that the person who asked the question responded to my post, but did not correct or clarify the context, which implies that I interpreted it correctly. He even suggested (from memory) that he might consider building my design.

If that person would like me to expand on that design, I would certainly be happy to.

Choosing drivers is a very difficult task. Partly because you can not trust the specs, especially on bass drivers. They may claim that a driver is functional from 30hz to 5000hz, but when you look at a response graphs and detailed specs, you see that to get 30hz requires a 5 cubic foot cabinet, and that the alleged 5000hz really craps out around 1khz. Under the best possible circumstance, you might squeeze 2khz out of it.

You also have to consider the rated Sensitivity of each driver. If the woofer is rated at 85dB and the midrange is rated at 90dB, that means to balance them, you have to get rid of 5db of sound from the midrange. It is difficult to find a true midrange to smoothly and easily span the need frequency range, so I choose 4" Full-Range drivers that go pretty deep and pretty high, and would have an easy time in the selected frequency range.

You also have to consider the power rating of the speakers. The midrange I was considering using, were only rated at 60w. I was trying to come up with a speaker with a solid 100w power rating. So, I put TWO 4" full range drivers in series, meaning the combined power of the two was functionally 120w. The output in terms of loudness is the same as one 4" driver.

Even a simple speaker design is still a complex project. I have tentatively selected drivers for the speaker design I submitted. Again, if the person who asked the question would like a list of those components, I can provide that.

Steve/bluewizard
 

Matyam

Active Member
BlueWizard said:
Two aspects were involved in the original question, which I previously quoted.

1.) Anything goes
2.) A Project

1.) Anything goes - I rejected that as a pointless discussion, even the most advanced design labs do not have infinite resources, infinite money, infinite technical expertise, and (metaphorically) an infinite place to put it all.

2.) A project - Which to me implied he was intending to build a DIY speaker - Speaker Design Project. Which is one of many reasons why I rejected premise number 1.

I responded to a clear context, though I may have inferred that context, it none the less framed my response.

Chasing Sub-30hz in the context is a piped dream, as you will find if you look at the low end response of a vast majority of stand alone speakers out there. So, there is a large context, which is my introducing a means by which people can find speaker driver equivalents, as in one 6.5" equal two 5" drivers. That sets the overall tone of Drivers and Stand Alone full-range speaker. The second context was the specific question asked. He did not say - Help me design a System that can achieve 20hz response? Others cover that unrelated topic. What is did say was - Help me with a SPEAKER DESIGN PROJECT? Both those contexts frame and continue to frame my response.

I responded with a very realistic speaker design, that a DIY builder could potentially afford, and with few technical complications beyond those found in any basic speaker design/built.

Yes, a compilation of drivers in a box does constitutes a speaker system, but when you add a Subwoofer, the system and the associated electronics become substantially more complicated, and especially so when you ignore the context of the original question.

I never claimed that multi-speaker AV systems and even multi-speaker stereo systems could never reach in the vicinity of 20hz. What I said repeatedly, ...repeatedly..., in the context of the original question, was that in a single cabinet full-range speaker, as would be associated with a Speaker Design Project, significant Sub-30hz response was difficult and expensive. I've seen nothing that has been said so far that contradicts that statement in the context it was made.

I've never said that Subwoofers don't do what Subwoofers clearly do. I never said that those with many thousands to spend could not come close to achieving Sub-30hz response. In fact, I gave examples of individual speakers that did just that.

What other think they thought I said, is irrelevant, I responded to a question with my best and reasonable interpretation of the context, and as I have said, nothing has been said to sway me from that opinion. The fact that other choose to ignore the clear context, and the fact that other choose to replace what I said, with what they wanted to hear, is not in my control.

In the context of the question asked, I stand by my answer. I also notice that the person who asked the question responded to my post, but did not correct or clarify the context, which implies that I interpreted it correctly. He even suggested (from memory) that he might consider building my design.

If that person would like me to expand on that design, I would certainly be happy to.

Choosing drivers is a very difficult task. Partly because you can not trust the specs, especially on bass drivers. They may claim that a driver is functional from 30hz to 5000hz, but when you look at a response graphs and detailed specs, you see that to get 30hz requires a 5 cubic foot cabinet, and that the alleged 5000hz really craps out around 1khz. Under the best possible circumstance, you might squeeze 2khz out of it.

You also have to consider the rated Sensitivity of each driver. If the woofer is rated at 85dB and the midrange is rated at 90dB, that means to balance them, you have to get rid of 5db of sound from the midrange. It is difficult to find a true midrange to smoothly and easily span the need frequency range, so I choose 4" Full-Range drivers that go pretty deep and pretty high, and would have an easy time in the selected frequency range.

You also have to consider the power rating of the speakers. The midrange I was considering using, were only rated at 60w. I was trying to come up with a speaker with a solid 100w power rating. So, I put TWO 4" full range drivers in series, meaning the combined power of the two was functionally 120w. The output in terms of loudness is the same as one 4" driver.

Even a simple speaker design is still a complex project. I have tentatively selected drivers for the speaker design I submitted. Again, if the person who asked the question would like a list of those components, I can provide that.

Steve/bluewizard
Steve going back my yardstick are a old friends linn keltiks with a apparent 20-20khz response BUT as in my opinion a flat response with some of the music I like sounds well FLAT.My hearing supports a house curve from low down which could be catered by a infinite baffle sub system or next a sub 1 or 2.In my world my chevy 350 cv s do what i want at the moment as the cheque for the grand utopias is in the post.Your design is along the lines I was thinking but as I would like all in one without the monolithic rectangle boxes and this being a factfinding mission I am all ears.Now we all know that aesthetics play a major part in the price of speakers but for instance in your opinion of a £1000 £5000 £10000 pair of speakers what percentage oft the retail value is made up of the drivers and cross overs . Obviously grand utopias or the like would do but what drivers can I expect from a limited 36"high box to exceed my cerwin vegas response thanks.
 

MemX

Well-known Member
Matyam, you might like to have a look at the diyAudio forums as well - they have a number of forums that cover all manner of speakers and the design of them, from the plain old sealed sub, through more complex horn design, all the way up to the exotic tweeters that I don't think I understand! :laugh: The wealth of knowledge on there blows my tiny little mind so it is a great place for learning :)
 

mattkhan

Distinguished Member
Obviously grand utopias or the like would do but what drivers can I expect from a limited 36"high box to exceed my cerwin vegas response thanks.
for one benchmark, you may want to look at the SEOS 1099 flatpack available from diysoundgroup in the US, this is about 36" high cabinet and seems to be v highly rated over there. There are details in this post - A 3 way 99db multi configurable SEOS design - AVS Forum - including all the measurements you could need to see how it performs.
 

mattkhan

Distinguished Member
@BlueWizard frankly you're the only one ignoring the context here, the stated requirement was

So in a ideal world but only for performance sakes not aesthetically with a blank sheet what sort of speaker design would you have built money no object to cover the audio spectum 20-20khz and why ie size drivers, number off ? When my cv s go pop I would like a project.

and

So steve im using some cerwin vega e 715 s for my home cinema duties 15" ,.102 db sensitivity, 26-20khz .But in room I have measured flat at 21hz -6 at 17 hz equed .To be WAF I would need 7 X6.5 drivers per side to match? Is there a guide of driver size to rated output hz which seems more logical or not and has speaker design in your opinion moved on much as has been hinted at ?

It is quite simply a fundamental error to ignore a subwoofer in a home cinema context when full (audible) bandwidth reproduction is requested. You can choose to answer your preferred question if you like but that's not what the poster says he/she wants (unless they are going to full range all round?).

Note this doesn't mean to say there is anything wrong with your suggested approach to a main channel in such a system, just don't forget the bottom end!
 

BlueWizard

Distinguished Member
Steve going back my yardstick are a old friends linn keltiks with a apparent 20-20khz response .... Obviously grand utopias or the like would do but what drivers can I expect from a limited 36"high box to exceed my cerwin vegas response thanks.

As to the Linn Keltiks, that was an unusual speakers. Find me one of a similar price with similar specs today. Even adjusted for inflation, I doubt that you can find one.

The Grand Utopias, are grand indeed, and the price tag is grand beyond grand, which proves my point, in a single cabinet speaker, Sub-30hz gets expensive.

As to your Black Monkey Coffins. I doubt that there is much than can equal them for raw power, high output, deep bass, and impressive looks. I have no doubt that I could find speaker more refined than them, but not that would equal them in other areas. Better to enjoy what you have than to spend you time dreaming about something else. Though dreams do have their time and place.

Steve/bluewizard
 

Matyam

Active Member
Thanks guys taking time will peruse with much interest sites mentioned to find another level.
 

Matyam

Active Member
Two aspects were involved in the original question, which I previously quoted.

1.) Anything goes
2.) A Project

1.) Anything goes - I rejected that as a pointless discussion, even the most advanced design labs do not have infinite resources, infinite money, infinite technical expertise, and (metaphorically) an infinite place to put it all.

2.) A project - Which to me implied he was intending to build a DIY speaker - Speaker Design Project. Which is one of many reasons why I rejected premise number 1.

I responded to a clear context, though I may have inferred that context, it none the less framed my response.

Chasing Sub-30hz in the context is a piped dream, as you will find if you look at the low end response of a vast majority of stand alone speakers out there. So, there is a large context, which is my introducing a means by which people can find speaker driver equivalents, as in one 6.5" equal two 5" drivers. That sets the overall tone of Drivers and Stand Alone full-range speaker. The second context was the specific question asked. He did not say - Help me design a System that can achieve 20hz response? Others cover that unrelated topic. What is did say was - Help me with a SPEAKER DESIGN PROJECT? Both those contexts frame and continue to frame my response.

I responded with a very realistic speaker design, that a DIY builder could potentially afford, and with few technical complications beyond those found in any basic speaker design/built.

Yes, a compilation of drivers in a box does constitutes a speaker system, but when you add a Subwoofer, the system and the associated electronics become substantially more complicated, and especially so when you ignore the context of the original question.

I never claimed that multi-speaker AV systems and even multi-speaker stereo systems could never reach in the vicinity of 20hz. What I said repeatedly, ...repeatedly..., in the context of the original question, was that in a single cabinet full-range speaker, as would be associated with a Speaker Design Project, significant Sub-30hz response was difficult and expensive. I've seen nothing that has been said so far that contradicts that statement in the context it was made.

I've never said that Subwoofers don't do what Subwoofers clearly do. I never said that those with many thousands to spend could not come close to achieving Sub-30hz response. In fact, I gave examples of individual speakers that did just that.

What other think they thought I said, is irrelevant, I responded to a question with my best and reasonable interpretation of the context, and as I have said, nothing has been said to sway me from that opinion. The fact that other choose to ignore the clear context, and the fact that other choose to replace what I said, with what they wanted to hear, is not in my control.

In the context of the question asked, I stand by my answer. I also notice that the person who asked the question responded to my post, but did not correct or clarify the context, which implies that I interpreted it correctly. He even suggested (from memory) that he might consider building my design.

If that person would like me to expand on that design, I would certainly be happy to.

Choosing drivers is a very difficult task. Partly because you can not trust the specs, especially on bass drivers. They may claim that a driver is functional from 30hz to 5000hz, but when you look at a response graphs and detailed specs, you see that to get 30hz requires a 5 cubic foot cabinet, and that the alleged 5000hz really craps out around 1khz. Under the best possible circumstance, you might squeeze 2khz out of it.

You also have to consider the rated Sensitivity of each driver. If the woofer is rated at 85dB and the midrange is rated at 90dB, that means to balance them, you have to get rid of 5db of sound from the midrange. It is difficult to find a true midrange to smoothly and easily span the need frequency range, so I choose 4" Full-Range drivers that go pretty deep and pretty high, and would have an easy time in the selected frequency range.

You also have to consider the power rating of the speakers. The midrange I was considering using, were only rated at 60w. I was trying to come up with a speaker with a solid 100w power rating. So, I put TWO 4" full range drivers in series, meaning the combined power of the two was functionally 120w. The output in terms of loudness is the same as one 4" driver.

Even a simple speaker design is still a complex project. I have tentatively selected drivers for the speaker design I submitted. Again, if the person who asked the question would like a list of those components, I can provide that.

Steve/bluewizard
So steve regarding your speaker designs, If I took my 15" woofers out to use as my bottom end as I know there capabilites what would you suggest to use above full range drivers considering the woofers 102 db sensitivity.
 

BlueWizard

Distinguished Member
Are you talking about your Cerwin Vegas?

In all honesty, I would not recommend rebuilding them. Keeping in mind, building speakers is a painfully complex task. If you read the discussions on DIYAudio.com in the Multi-Way forum, you well get a sense of just how complex it is.

I've been working on the design I posed for several years, though only casually in my mind.

The original concept was on the left of the two designs I posted. The idea was a 3.5-way design with the 10" and the 8" running in parallel at more or less below 200hz. Then from 200hz and above the 8" 3-way would take over. However, there were complications in that design, since I broke tradition and had two different sized speakers in the 0.5-way aspect.

So, I decided to make it a plain 3-way with the 10" driver as the single bass speaker. Next was the issue with crossovers. I originally thought that a 800hz/5000hz would work. But, I'm using 4" Midrange drivers, and at 5000hz, the start to Beam. That is, the field of sound begins to narrow, which creates a conflict in the smooth transition from a beaming Midrange to a non-beaming tweeter. If I force the crossovers down to 500hz/4000hz, I'm right on the edge of where the Midrange starts to beam, so that is probably a workable solution.

The last alternative was to drop down to 350hz/3000hz which put the Midrange in its best workable rang. But this has an additional complication, there tends to be a peak in the power distribution of music in the 250hz to 500hz range, centered on 355hz. If that range is running at 10 watts, the range just below it is running at 4 watts, and the range just above it is running at about 2 watts. So he see the peak power demand in this range is very high relative to the rest of the frequency spectrum.

Which leads to the concern that if I cross below 500hz, then I am putting that peak power demand on the Midrange speaker which are far less able to handle it compared to the bass driver.

Yada-yada, blah-blah-blah - what this adds up to is .... IT'S COMPLICATED.

I think as it stands now, I will use the Dayton Reference Aluminium 10" Bass driver. TWO 4-ohms 4" Dayton Reference Aluminium Full Range drivers, and a matching Dayton Silk Dome Tweeter, though I have decided specifically which one yet. I will cross at 500hz/4000hz, even though a few people have claimed that, for some undermined reason, 4khz is not the ideal place to cross Mid-to-High.

Then you need to download some software that will let you run simulations on a give speaker. Mine is complicated by the fact that my design is trapziodal, though I can calculate the equivalent in a rectangular cabinet. There are free version of Software out there.

Enter these parameters into the Software for the the specific speaker you are using. In this case it is the Dayton RS270-8 -

Thiele-Small Parameters
  • Resonant Frequency (Fs)27 Hz
  • Resonant Frequency (Fs)27 Hz
  • DC Resistance (Re)6.84 ohms
  • Voice Coil Inductance (Le)0.93 mH
  • Mechanical Q (Qms)2.08
  • Electromagnetic Q (Qes)0.61
  • Total Q (Qts)0.47
  • Compliance Equivalent Volume (Vas)3.4 ft.³
  • Mechanical Compliance of Suspension (Cms)0.57 mm/N
  • BL Product (BL)10.3 Tm
  • Diaphragm Mass Inc. Airload (Mms)35.8g
  • Maximum Linear Excursion (Xmax)6.6 mm
  • Surface Area of Cone (Sd)346.4 cm²
As it turns out, the site I am getting this information from has used a program called BassBox 6 Pro to determine the ideal cabinet sizes -

  • Sealed Volume ... 1.38 ft.³
  • Sealed F3.... 49 Hz
  • Vented Volume ... 4.5 ft.³
  • Vented F3 ... 25.6 Hz (F3 means -3dB response)
Which brings up a problem I mentioned before. A Sealed Cabinet can be small, but you limit the bass out put. In this case, it is limited to 49hz.

A vented cabinet can go super deep, down to 25.6hz, but it is a 4.5 Cubic Foot cabinet. (127.5 liters)

Just for reference, the speaker in the following photo, which I built in about 1985 are about 2.5 cubic feet (28"H x 17.5"W x 13"D). For the ideal size of the above driver, the cabinets about need to be nearly TWICE that big.

diy-diamond-sm-jpg.144630


So, the purpose of the simulation is to find a compromise on the bass cabinet size that can give you a bass response close to what you want in a cabinet size you can reasonably tolerate.

If the lower bass cabinet in my original design is 24 inches deep, then the cabinet volume becomes 3.2 ft². Though you have to subtract the volume of the 10" bass driver.

Then we have to consider the output of the speakers. The 10" put out 87dB, unfortunately the Midrange only put out 84.2dB. That is less than ideal, but I might still be able to work with it. The Tang Band W4-1052D-4 4" midrange puts out 87dB, but it cost more money and has a lower power rating.

So, my point in telling you all this, even though it doesn't directly answer you question, is to establish that DIY Speaker Design is complicated.

As I said, I have been pondering the design I posted for years. Though since I can't afford to build it, I'm in no hurry. Constantly trying to refine it. Constantly trying to work out fine details of the design should I ever be in a position to actually build it.

So, let me say this -

Yada-Yada-Yada, Blah-Blah-Blah
... designing speakers is complicated.

There are several speaker design sites that have build and tested speakers, and published them as proven design. If this is your first speaker built, it is far far better to copy an existing design, than to try to create on from scratch. The custom design can be from simply bookshelf to elaborate much woofer designs.

For example, here is a speaker designed and built by a hobbyist in the UK -

tism168.jpg

So, again, best work with a proven design, of which many many designs are posted in various Audio Forums.

Sorry for rambling.

Steve/bluiewizard
 
Last edited:

Jameskatie

Distinguished Member
It is very complicated but I think your over complicating the very basics there, you do known that if you knock the xover of a mid down from 4k you don have to move the lfe point aswell which you seem to think you do which brought you another problem when solving another
 

BlueWizard

Distinguished Member
We are talking about a single speaker (or pair of speakers), consequently there is no LFE, there is only that speaker and how it performs. We are talking about the design and construction of that speaker, not how to integrates it into a larger more complex system.

Now reasonably the system you put the speaker in will have some influence on the design. But as it stands, this is a stand alone speaker.

Both Low/Mid and Mid/High have to be in a reasonable working range for the drivers selected. Given that the Mids are 4", that leaves 3000hz or 4000hz on the high end. On the low end, the choices seem to be 350hz and 500hz. I explained the reason, and the advantages and disadvantages of both choices. While it is not locked in stone, the Midrange typically covers 3 octaves. But again, there is flexibility in that.

Three octave ups from 350hz is actually 2800hz. Three octaves up from 500hz is 4000hz. The 350hz crossover puts alot more strain on the Midrange drivers, because they cover the peak power band in the 250hz to 500hz range. Crossing at a higher 500hz, raise the Midrange right the the edge of its best functional range. All round it is a very fine balancing act.

As I said, the 3 octave Mid is not etched in stone, but it is very common. Though in a 3-way design, there is a limit to how low the tweeter can functionally go. It has to be over rated. By that I mean if it is functional down to 1500hz, then you really need to cross it in the range of 2500hz or higher to minimize excursion and to increase power handling.

Generally it is 3 octaves on the Bottom, 3 octaves in the Mid, and 4 octaves on the high end. But again, a lot of flexibility. Typically drivers do not work out on those boundaries, so you make do with the drivers in the range they do work in.

Steve/bluewizard
 

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