I understand the relation of impulse to FR of an FFT. Often measuring sw will use either of an impulse or a sweep as a stimulus to measure
dave
dave
I've never said that 'the FR response of a vintage Lorenz was near perfect'. You're making that up.
I've said that compared to measurements of other 8" full range drivers the Lorenz seems to have very well controlled directivity. Something you don't find often in wide band drivers. Just look at the Alpair 7.3. Awful. The Tymphany TC9 is much better.
The Lorenz's on-axis frequency response has to be equalized. But that's true for virtually all full range drivers.
Toole did say that? I don't think that is true. Care to post references?
By the way, gated measurements are a good approximation of what the anechoic response at higher frequencies is. Such measurements reveal more than what any full range manufacturer dares to show. Some even use cheap tricks to make the response of their drivers look good.
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What tools are you talking about?
Progress is continuing, you just have to have patient. You seem to want to use your rock to try to explain the world.
dave
No. I just accept what has been discovered so far. One step after the other. First learn how to use a hammer then and only then you can move on and learn how to use other tools. You on the other hand seem to fight the hammer. In my opinion that's not how progress is made.
I believe that he very lowest distortion low frequency bass that one can obtain will be found in small driver back loaded large mouth horn speakers.
Without horn loading, xmas will be large to obtain bass and large xmas equals distortion. Without a horn coupled to it, a small speaker has to move way too far to produce any bass at all. In a properly designed horn, the driver will move hardly at all.
I have built large front loaded horns and I have a set of back loaded horns with 6 inch Fostex full range and they have produced the cleanest bass that I have come across. Everyone that has heard them, has mentioned how clean they are.
After listening to properly designed horns with small drivers, subs sound ever so muddy (but powerful).
Just my 25 cents.
The simplest distortion test of a low frequency speaker is to listen to it and then try to tell what instruments are making the sound.
With a sub at 40 to 70 hz, everything comes through as a thud.
With a correctly designed large horn speaker, bass fiddles, bassoons, pianos and harps come through as distinct sounds. You can hear the reeds working on woodwind instruments.
While listening to the low frequency instruments, if you cannot tell what instrument that it is, your speaker has too much distortion.
With a sub at 40 to 70 hz, everything comes through as a thud.
With a correctly designed large horn speaker, bass fiddles, bassoons, pianos and harps come through as distinct sounds. You can hear the reeds working on woodwind instruments.
While listening to the low frequency instruments, if you cannot tell what instrument that it is, your speaker has too much distortion.
hi Dennis - with regards to a six inch driver BLH, what do you find for path, expansion and mouth size to obtain good result?
the FE166 sim below is for small mouth examples of BK16 and a "BIB"
the FE166 sim below is for small mouth examples of BK16 and a "BIB"
An externally hosted image should be here but it was not working when we last tested it.
In this video: https://www.youtube.com/watch?v=7vn6hQHRgzk Toole pretty much sums up he does not put much faith at all in stereo reproduction sounding like a real performance after all his years of testing.
I agree that very low distortion bass can be produced by horn loaded drivers. But I disagree that you can't get powerful non muddy bass from a subwoofer. It really depends on the design. Take this one that I built with sub-percent distortion at 97dB at 1m with 2.83v drive. It's actually capable of pro level SPL and still remain clean. You certainly can hear all the bass instruments clearly when this is paired with a good low distortion top in a FAST.
Do you have any distortion measurement of your BLH?
Attachments
measurements outdoors seem ok and pretty good. The DUT must develop enough power to overcome ambient noise but would be no problem during quiet times even with smaller fullrange measured at 1 & 2M. The result seems at least good enough in the bass to establish cutoff/rate, etc. Its good to do them when the temperatures are like comfortable room temps.
I have had t-lines which sound very bad in the upper bass - my horn experience is extremely limited to what's laying around and PA-ish including one set of Edgarhorn 100 plus his 40Hz design, EV-Sentry IV, Klipschorn, PV FH1, 50Hz folded. For blh, BK20 and doubt if will gain much more experience in that area as am old. I used to feel that low moving mass per unit cone area was the way to go but have heard reasonably good compromises including a BP4 mated to a sealed box 2-way with no crossover other than a small inductor to lower the port leakage area. Sometime ago, I found Karlson enclosures to be one acceptable compact compromise vs full front load horn.
subjective realism in the "bass" certainly needs good treble power.
I have had t-lines which sound very bad in the upper bass - my horn experience is extremely limited to what's laying around and PA-ish including one set of Edgarhorn 100 plus his 40Hz design, EV-Sentry IV, Klipschorn, PV FH1, 50Hz folded. For blh, BK20 and doubt if will gain much more experience in that area as am old. I used to feel that low moving mass per unit cone area was the way to go but have heard reasonably good compromises including a BP4 mated to a sealed box 2-way with no crossover other than a small inductor to lower the port leakage area. Sometime ago, I found Karlson enclosures to be one acceptable compact compromise vs full front load horn.
subjective realism in the "bass" certainly needs good treble power.
How much of our views on distortion measurements are based on the limitations of all the speakers we hear, making so much distortion that the measurements become almost meaningless?
For example, why can't I set up 2 loud speakers, and place a microphone equi distant, and get "complete" destructive interference? *
I think the answer is simple. Speakers compared to amplifiers are so highly distorting in their transform of electrical signal to sound.
Because the distortion in conventional speakers is so high, and non linear in nature, measuring which type of distortion a person likes better is the order of the day and the significance of measurement has to be judged not with reference to a bass line assumption that it can be 0.
This subjective choice of preferred types of distortion, like fashion this is highly subjective and cultural. Just look at the never ending discussions about speaker mounting in this forum.
We see people (in this community) obsessed with Horns, for their dynamics, we see people obsessed with bass reflex (in this community) for their better bass frequency response, we see people obsessed by the directivity pattern (in this community), we see people obsessed with full range speakers (in this community) for avoiding nasty behaviour at the cross over frequency. Some people tell me dipoles are significantly better but I cant some up the attraction of these in one phrase and have less experience of them.
It is definitely true that some speakers sound more terrible than others, but I find it rare to see much agreement over which speaker mounting is superior.
Personally I lay most of the blame on the mechanical nature of using a moving coil in a magnetic field, held in place by spring structures, and propel a cardboard, metal or plastic diaphragm back and fourth. This is clearly highly dependent on mechanical properties that change over time, and production runs, and has a very limited bandwidth and nearly always needs some electrical compensation to avoid resonances, for example crossovers (multiway), notch filters (full range) and DSP.
Nearly all microphones are electret, or electrostatic in nature, this tells us some thing important, about the limited possibilities of coupling heavy lumps of copper to a diaphragm.
This said I feel when comparing speakers of similar types, measurement can be very useful but in my opinion you have to understand what you are measuring and what your measurements are telling you, and that they unlike abstract math are not absolute in nature and control of measurement conditions is critical.
As a digression and to add further comp
My limited exposure to electrostatic speakers, suggests they sound more similar than they do different and consider these in my experience significantly better than moving coil speakers in the human voice range, but they often have very narrow directivity patterns as the frequency becomes higher, making them less successful in PA. This said combining these with moving coil loud speakers for drums and bass, to overcome dynamic range and bass response issues in electrostatic speakers is still far from a universal solution and does not resolve all the issues.
Personally I believe every hifi person in this discussion is doing them self no favours if they have never heard alternative approaches to moving coil speakers, and would be well advised to listen to some electrostatic speakers, and then ask them selves how much of there views on distortion measurements are based on their limitations of the sources, making so much distortion that the measurements become almost meaningless at a general level.
* Quad does destructive audio cancellation for QA purposes on the ESL 63 and later electrostatic speaker models.
For example, why can't I set up 2 loud speakers, and place a microphone equi distant, and get "complete" destructive interference? *
I think the answer is simple. Speakers compared to amplifiers are so highly distorting in their transform of electrical signal to sound.
Because the distortion in conventional speakers is so high, and non linear in nature, measuring which type of distortion a person likes better is the order of the day and the significance of measurement has to be judged not with reference to a bass line assumption that it can be 0.
This subjective choice of preferred types of distortion, like fashion this is highly subjective and cultural. Just look at the never ending discussions about speaker mounting in this forum.
We see people (in this community) obsessed with Horns, for their dynamics, we see people obsessed with bass reflex (in this community) for their better bass frequency response, we see people obsessed by the directivity pattern (in this community), we see people obsessed with full range speakers (in this community) for avoiding nasty behaviour at the cross over frequency. Some people tell me dipoles are significantly better but I cant some up the attraction of these in one phrase and have less experience of them.
It is definitely true that some speakers sound more terrible than others, but I find it rare to see much agreement over which speaker mounting is superior.
Personally I lay most of the blame on the mechanical nature of using a moving coil in a magnetic field, held in place by spring structures, and propel a cardboard, metal or plastic diaphragm back and fourth. This is clearly highly dependent on mechanical properties that change over time, and production runs, and has a very limited bandwidth and nearly always needs some electrical compensation to avoid resonances, for example crossovers (multiway), notch filters (full range) and DSP.
Nearly all microphones are electret, or electrostatic in nature, this tells us some thing important, about the limited possibilities of coupling heavy lumps of copper to a diaphragm.
This said I feel when comparing speakers of similar types, measurement can be very useful but in my opinion you have to understand what you are measuring and what your measurements are telling you, and that they unlike abstract math are not absolute in nature and control of measurement conditions is critical.
As a digression and to add further comp
My limited exposure to electrostatic speakers, suggests they sound more similar than they do different and consider these in my experience significantly better than moving coil speakers in the human voice range, but they often have very narrow directivity patterns as the frequency becomes higher, making them less successful in PA. This said combining these with moving coil loud speakers for drums and bass, to overcome dynamic range and bass response issues in electrostatic speakers is still far from a universal solution and does not resolve all the issues.
Personally I believe every hifi person in this discussion is doing them self no favours if they have never heard alternative approaches to moving coil speakers, and would be well advised to listen to some electrostatic speakers, and then ask them selves how much of there views on distortion measurements are based on their limitations of the sources, making so much distortion that the measurements become almost meaningless at a general level.
* Quad does destructive audio cancellation for QA purposes on the ESL 63 and later electrostatic speaker models.
I agree that very low distortion bass can be produced by horn loaded drivers. But I disagree that you can't get powerful non muddy bass from a subwoofer. It really depends on the design. Take this one that I built with sub-percent distortion at 97dB at 1m with 2.83v drive. It's actually capable of pro level SPL and still remain clean. You certainly can hear all the bass instruments clearly when this is paired with a good low distortion top in a FAST.
Do you have any distortion measurement of your BLH?
How do 20Hz-40Hz square waves measure with this set up?
Can you post IR.wav for this measurement?
What is your experience with this?
What are test conditions?
What level of cancellation have you achieved?
Let me see if I still have the data file for this measurement to pull the IR wav file.
I am not sure how it will do for square waves. Those are very hard to achieve at bass frrquencies because it means phase flat at this frrquencies. Very few speakers are phase flat 40Hz to 100Hz.
When you do 'conventional' measurements of speakers, you are assuming it is a 1D transmission chain. It is NOT. It is 1D in and 3D out.
Absolute Listening Tests-Further Progress shows that the 1D transmission chain as measured by FR, THD bla bla is good enough.
What is still very far from right is the Room Interface Profile. The false prophets Floyd et al pretend to pontificate on this but there's a lot they don't know.
Out of these (and other) tests, we developed our own take on 'conventional' DBLTs on speakers which we used for nearly 2 decades.
Several important points come out of this.
Of course these DBLTs were done with music (including some of my and other victims own recordings)
If the criteria was dinosaur footsteps, I would expect a sub to be useful for the little 6ltr box.
For these, I developed my patented Powered Integrated Super Sub technology. For some reason, Marketing never liked this term 😕
[!] that's not to say I don't think low THD isn't worth pursuing. When I first head the ESL63, I thought the gear was faulty as audible LF THD was so low. But its mid & treble performance puts it down the list in DBLTs. My ultimate stereo speaker would have electrostatic bass but Moving Coil mid & treble.
Absolute Listening Tests-Further Progress shows that the 1D transmission chain as measured by FR, THD bla bla is good enough.
What is still very far from right is the Room Interface Profile. The false prophets Floyd et al pretend to pontificate on this but there's a lot they don't know.
Out of these (and other) tests, we developed our own take on 'conventional' DBLTs on speakers which we used for nearly 2 decades.
Several important points come out of this.
- often a speaker with much higher measured THD is described as having lower distortion .. even by experienced listeners [!]
- The speaker that has come out the best in these tests is a small 6ltr box with no response below 70Hz. It is often described as having 'tuneful' bass and preferred ... even by experienced listeners who like big speakers. It's competition in these DBLTs has always been bigger, more expensive speakers.
- the victim ALWAYS chooses his own music
- & levels
- has complete control over switching
- no one else is in the listening room
- and he can spend up to 1/2 a day doing the test.
Of course these DBLTs were done with music (including some of my and other victims own recordings)
If the criteria was dinosaur footsteps, I would expect a sub to be useful for the little 6ltr box.
For these, I developed my patented Powered Integrated Super Sub technology. For some reason, Marketing never liked this term 😕
[!] that's not to say I don't think low THD isn't worth pursuing. When I first head the ESL63, I thought the gear was faulty as audible LF THD was so low. But its mid & treble performance puts it down the list in DBLTs. My ultimate stereo speaker would have electrostatic bass but Moving Coil mid & treble.
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The last set of horns that I built were DecHorns pretty much to plan. The throat is about 2 inches x 10 inches. Its sort of hard to actually determine the mouth area. If I just measure the opening on each side of the center column, it is 42 inches by 16 inches x two sides = 9.3 square feet.
But maybe , since they are corner horns, one should just measure across the diagonal (5 feet) x 3.5 feet high= 17.5 square feet. The path is about 6 feet, but could be a few feet longer depending on which part of the corner that you measure from.
In this discussion, others have given a URL to a talk by Toole. I listened to it and pretty much agree with all that he said. He mentioned the importance of "being enveloped by sound" as very important. With their large output area, these speakers really do envelope you. I have a review on DecHorns in the archives and mention how much sound that they make. It really is a different experience.
My other horn speakers were built from the tables in "Hi-Fi Loudspeakers and Enclosures" by A.B. Cohen 1967. They also were corner horns, but a bit bigger than the Decs. I made a mistake in my youth by using too large of a driver with not a low enough total Q and with too low of a Fs.
Cohen explains the errors of my ways.
size matters 😀 sometimes its a matter of recording perspective whether one is back in a room/hall at some distance with lots of reflective sound or the event is re/produced up close in the listener's room with that room dominating. Are your big speakers the "Dean - cornerless corner horn"
piano with orchestral dimensions from the 1930 "King Of Jazz" (Rhapsody In Blue segment) which is available for free at archive.org
piano with orchestral dimensions from the 1930 "King Of Jazz" (Rhapsody In Blue segment) which is available for free at archive.org
I had forgotten all about the University Dean, so I Googled it and ended up reading an entire pdf of a 1959 Hi -Fi Magazine that was archived that had Dean ads in it.hi Dennis, I meant the Abraham Cohen design - thought you might have built the "Dean"
1959 was a little before my time, but by the time I got into high school a few years later, that was the vintage of the hi-fi equipment being handed down or on the "used" shelve. I still have a 1959 Dynaco MkII that was handed down to me uncompleted. I completed it. Just a few months ago, I replaced its four in one capacitor that had all the pcbs leaking out.
My dad was a sign painter and we had lots of used plywood around, so I built a clone Jensen Imperial and ran it in mono mode off the Dynaco in his shop. It moved a lot of air.
And I still have a 1959 Webcor 4 track reel to reel that is just now getting a new drive belt.
Thanks for the memories.
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