As already mentioned, axial response can be straight enough when power response and off-axis responses are optimized too. Problems are expected if axial response is optimized flat but everything else is totally ignored; not measured, not simulated, not in mind. Sound could be death and stuffed but harsh and too bright at the same time due to power dip at the crossover area and power hump about octave above.
This is not the worst example but some problems are clearly visible. Same drivers and measurements in both cases.
1)Axial response (black) is fully optimized, but power (blue) and directivity index (red) are totally ignored. Crossover slopes are electrically 5/6th order.
An externally hosted image should be here but it was not working when we last tested it.
2) Axial (black) and power (blue) responses are optimized with weighting of 50/50%. Crossover slopes are electrically 2nd order.
An externally hosted image should be here but it was not working when we last tested it.
They are low quality speakers. I believe they don't have an elaborated crossover but single caps direct to the mid and tweeter. They are only an example regarding to the size and the 3 way design.
Yes basically (although there are other factors at the limit) the smaller you go the easier it is to integrate the woofer into the tweeter as it is a lot to do with the physics of how a cone radiates and the larger the cone the less off axis response you will get after brake up.
However if you like 8 inch drivers I would not be put off. Off axis response is not he whole of the story either.
If you could describe a bit better what it is you want to achieve we might be able to find the best compromise. When you say you don't find 5.5 or 6 inch drivers work for the volume you listen at - do you mean your amplifier runs out of power? The speakers start to distort due to being over driven (possible heat compression), the bass excursion causes the driver to distort as it is coming to the end of its linear working range?
If its the amplifier - power is cheap these days buying a bigger amp would be the obvious solution.
A different solution to the off axis response might be to find a tweeter that is horn loaded, that way the horn will limit the tweeters off axis response making it more similar to the woofers.
If you are getting compression distortion from heat then a Higher power but smaller drive unit might provide what you are looking for.
If it is bass excursion causing the problem then a smaller speaker supplemented by a sub-woofer would enable you to have the improved off axis response and limit the bass in the speaker handing over to a sub-woofer for low bass.
If you have found you just really like the sound of 8 inch drivers crossed into tweeters, you might find that your ear is more sensitive in this region and that actually for you the loss of off axis response is actually what you like about the speakers!
Below of a different approach to combining the scan speak and tweeter concentrating more on off axis responses. there is still a region where you can see in the direction graphs the lines pull together as the tweeter becomes dominant. There is a limit to what makes sense to compromise. (This is just a driver simulation it has no box or baffle)
However if you like 8 inch drivers I would not be put off. Off axis response is not he whole of the story either.
If you could describe a bit better what it is you want to achieve we might be able to find the best compromise. When you say you don't find 5.5 or 6 inch drivers work for the volume you listen at - do you mean your amplifier runs out of power? The speakers start to distort due to being over driven (possible heat compression), the bass excursion causes the driver to distort as it is coming to the end of its linear working range?
If its the amplifier - power is cheap these days buying a bigger amp would be the obvious solution.
A different solution to the off axis response might be to find a tweeter that is horn loaded, that way the horn will limit the tweeters off axis response making it more similar to the woofers.
If you are getting compression distortion from heat then a Higher power but smaller drive unit might provide what you are looking for.
If it is bass excursion causing the problem then a smaller speaker supplemented by a sub-woofer would enable you to have the improved off axis response and limit the bass in the speaker handing over to a sub-woofer for low bass.
If you have found you just really like the sound of 8 inch drivers crossed into tweeters, you might find that your ear is more sensitive in this region and that actually for you the loss of off axis response is actually what you like about the speakers!
Below of a different approach to combining the scan speak and tweeter concentrating more on off axis responses. there is still a region where you can see in the direction graphs the lines pull together as the tweeter becomes dominant. There is a limit to what makes sense to compromise. (This is just a driver simulation it has no box or baffle)
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I believe that this is a very common "adapted hearing habit", because most of us have grown up listening to this kind of (cheap supermarket-brand) speakers.
It synchronizes also with the well known concept of BBC-dip in axial response which is described as giving pleasant sound, perhaps because hearing is most sensitive around 3kHz.
Third, I have noticed that many in-room decay/CSD/RT measurements show higher decay (higher reflectivity of walls/longer reverberation between walls) between 1-3kHz.
In general, I think that dvjorge, you have cognitive dissonance between your ideal speaker construction and the sound you like. This is not so simple as you think, that certain loudspeaker driver's physical properties have typical sound! Anyway, this discussion is educative!
It's better (best) to have all the speakers on axys.
Same as the old JBL (there is a thread here at DIYaudio about a guy who wanted to redo the cabinets, but he didn't consider to make that significant change)
See ? I made one year ago a speaker with a 4 " woofer, a 2" midrange and the little dayton mini AMT as the tweeter. Something that is difficult to find on the market
It can smooth power, it can not compensate for the acoustic limitations of a speaker that doesn't blend with the room.
There are two issues. One is a consistent dispersion. Eg your wall reflections can have the same response as the direct sound so they don't sound more distinct than they should.
The other is an appropriate dispersion. Eg you can choose which walls are involved in the first place.
Another way you can avoid the woofer top end, if that is your choice, is to lower the crossover frequency.
As someone said, this is all educative. I respect all the points and opinions, however, there many, hundreds of two way designs using 8" drivers and metal dome tweeters. I have found many of them googling the web, and some of them carrying the name of a good brand. It isn't impossible and not necessary has to be a bad sounding speaker. I don't think I have an over-sensitivity that makes me like an off axis speaker. I grew up listening good a audio system. Since I was 12, I began to listen to Altec Lansing Duplex speakers with tube amplifiers (my parents had it since 1955) Since that, I have had a decent audio system all my life. Coming back to the point, Canton, Linn, Kef, JBL, Klipsch, and many more companies have or have had a two way design using 8" drivers. I doesn't convince me that the result must be a bad sounding speaker.
Here is one made by JBL (studio monitors) 4208 model.!
https://www.jblpro.com/pub/recording/4200.pdf
https://www.jblpro.com/pub/recording/4200.pdf
Andrew, I find small drivers distorting if you rise the volume a little bit. This obligates you to listen to the speakers at low volume all the time. They also don't produce a good bass and the music doesn't have the right "body." I am giving you an example. Time ago, I owned the Monitor Audio Silver S10 floorstanding, at the same time I had my Monitor Audio Silver S2 bookshelf ( I still keep them) I ended selling the Silver S10 floorstanding because they couldn't produce the same sound the S2 bookshelf deliveries. Same company, same line, one set costing 3 times or more than the other, and the floorstanding wasn't able to sound as the bookshelf does. The only difference is the 7" driver the bookshelf has. Many of my friends in this hobby didn't believe it until I brought them to my home to do a demo. Everybody agrees the bookshelf was a better sounding speaker. Same electronic, same music, same cables.! This has been my experience when I go to hi-fi stores to listen to new models.
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There were many older speakers that used a larger woofer (eg 8/10/12" or something used relatively high for its size), and a larger cone tweeter, that sounded good.
These cone tweeters could have a more narrow dispersion that may have reduced some issues such as diffraction and wall reflection at mid and higher frequencies, as might the woofers.
Still, there was nothing outstanding about them. Modern mainstream has fixed some issues and introduced others. Some of these new issues I do not like, and can't get used to.
These cone tweeters could have a more narrow dispersion that may have reduced some issues such as diffraction and wall reflection at mid and higher frequencies, as might the woofers.
Still, there was nothing outstanding about them. Modern mainstream has fixed some issues and introduced others. Some of these new issues I do not like, and can't get used to.
Sorry you if you felt I was saying you can’t make a good 8” 2 way or that this was your hearing, I was just exploring possibilities.
As you ( and I earlier in the thread) have pointed out there are many very good sounding two way 8” designs, it requires compromises in some ways but can still sound very good and offers potentially higher sensitivity.
From the 80s when KEF used to publish technical descriptions, this shows the 103 Reference
http://www.kef.com/uploads/files/en/museum_pdf/70s/Reference_Series_Model_103_r.pdf
As you ( and I earlier in the thread) have pointed out there are many very good sounding two way 8” designs, it requires compromises in some ways but can still sound very good and offers potentially higher sensitivity.
From the 80s when KEF used to publish technical descriptions, this shows the 103 Reference
http://www.kef.com/uploads/files/en/museum_pdf/70s/Reference_Series_Model_103_r.pdf
Yes, but I have been looking to examples where the brand names designed them using an 8" mid-woofer plus a 1" metal dome tweeter. The JBL I posted has a crossover frequency of 2500 Hz and uses a 1" titanium dome tweeter. As it, you will find many speakers.
Andrew, I love them. Vintage Kef speakers have one of the sweetest sound I have listened from any British speakers.
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A common equation seems to be commercial = 5-10 times cost of DIY. I think commercial budget speakers would be much closer. The more you spend the more you potentially save (particularly with larger cabs). Troels Gravesen gives the big issue as size - bigger speakers are easier to make sound better, and cheap to build DIY - but costing a fortune to manufacture, store, and ship. I would say building to an existing and well documented design or getting a kit is the way to go to minimise the risk of an expensive white elephant.
Essential reading;
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Essential reading;
DIY-Loudspeakers
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