Hi,
Grovel at the feet of your guru. If you can't spot
drivel which that article is full of I'm not going to
try and educate you. Your a lost cause.
If you haven't worked it out, if you can't tell
the guy is full of subtle BS on your own, after
being told he is, you simply want to agree.
I'm not going there, arguing about things that are
half right but are wrong. That is a thankless task.
rgds, sreten.
Hi,
Your being a very self opinionated lost cause.
No I won't indulge your very lazy attitude.
Work it out for yourself, if you can.
Work it out for yourself that whilst in can
do DC, in reality it cannot be meaningful
in talking tripe about about response to DC.
(As response is not flat to DC, or in AC.)
The article goes way beyond the manufactures
claims, and is in many respects utter garbage.
Half right, in some claims, which are repeated
to death, and very wrong due to ignorance
and what is omitted, which is a lot.
rgds, sreten.
TBH I wonder what drugs are needed to
churn out such a verbose repetitive
missive, without really saying much.
Your being a very self opinionated lost cause.
No I won't indulge your very lazy attitude.
Work it out for yourself, if you can.
Work it out for yourself that whilst in can
do DC, in reality it cannot be meaningful
in talking tripe about about response to DC.
(As response is not flat to DC, or in AC.)
The article goes way beyond the manufactures
claims, and is in many respects utter garbage.
Half right, in some claims, which are repeated
to death, and very wrong due to ignorance
and what is omitted, which is a lot.
rgds, sreten.
TBH I wonder what drugs are needed to
churn out such a verbose repetitive
missive, without really saying much.
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Hi Sreten,
Thanks for your thoughts on this, genuinely - no one even bothered to comment when I voiced the idea maybe 8 years ago...
When you say "you'll get more than 3% distortion" - why? It is proven that a properly loaded horn will exact less distortion from a driver by limiting its excursion; that's why horns worked so well with the non-compliant paper cones of yesteryear: we're (I'm) applying the same idea here - the only difference is that a horn is passively pressurised by virtue of own oscillation, whereas I am actively pressurising it.
I take your point on the airline, but I suspect that owing to my probable misuse of language you're thinking of a high pressure low volume airline, which would most likely have been used in the 1930's example - workable given a very small throat volume and restricted bandwidth for that purpose. What I am proposing is a very large volume driven by a high powered fan: yes, you have to curtail the noise (same as fan-sub), but so what? If the fan sub works (within its limited bandwidth) then given the same or more air pressure/volume, why can't this?
Granted, you can calculate distortion/spl for any given horn by examining the mouth volume (PA guys have been doing this for years, especially with horn-loaded tweeters: the figures are pretty surprising & not in a good way!) and the calculations would apply to the relevant pressure chamber here; and also apply to the fan-sub enclosure btw.
By inducing active pressure (high volume air supply) you don't rely on the diaphragms natural inclinations. If you can supply enough volume/pressure to limit diaphragm excursion at DC, then you have a system that should follow down to DC. The process actually does the same as the fan-sub, just differently.
So, if the driving amp can take the diaphragm to maximum excursion, but we limit DC excursion through air-feed pressure, I'm sure we have a winner. Granted, I really don't know how a driver will respond to this kind of pressure, but given what we know about horn-loaded drivers, my gut tells me it'll be fine - you even get driver cooling thrown in for free! I've got two fans & an air conditioner running in my small 8' x 14' room right now (frikkin' hot here!); hell I could even shove air-con into the bargain
I don't get that
My idea uses a constant volume air supply which is modulated by a driver - to my mind it works the same as a simple transitor or triode. Relative amplitude & frequency are driven by the amplifier/driver combination - no variability in air-feed. Sure, you can vary the air supply pressure, but this would only be in the same manner as you vary volume on an amplifier by twisting the loud button one way or another - madness to really consider trying to manipulate a probable 1000W fan in line with program material.Given that the wavelength at 10 Hz is in the order of 1000', I think it's more than probable that in-room response will be pretty much self destructive; I think you'll be picking up more from outside the room than inside - phase inversion? Worth a try & not exactly difficult...
My thinking is a little "wet finger in the air" here
, but I know there was a short-lived trend for using stuffed corrugated hosing to supply sub-bass: obvious limitations, but worked for some. I guess if you limited even this to 20Hz you'd get "acceptable" distortion figures... More to the point, if this ~ 2-3" diameter is capable of producing adequate spl without causing undue distortion (horn throat diameter calculations apply), then it's pretty clear that you can have adequate pressurisation. I'm not suggesting the use of corrugated hosing, just making the point about the mouth diameter - easier to visualise adequate pressurisation in such an example rather than a maybe 18" opening.As always, options are unlimited. you can have an 18" driver firing into two chambers terminating in a limited diameter opening (not a port as such) or several drivers in a big chamber for that matter. If I had $18,000 to play with I'm pretty damn sure I'd find a way to make it work
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Just for giggles, I pasted all of it into a text file and it is 61 pages long, Libre office writer finds 41846 words (259014 Bytes as plain text). I would say this "review" is at least 20 times longer than it needs to be. Is it any wonder that it is self-published?
If you do some searches for J Peter Moncrieff, you will find many who find his writing style annoying (and many other less complimentary adjectives.) He apparently is one of those who believes that "demagnetizing" a CD changes its sound for the better.
Tom Danley patented a system vaguely like the one Jezz-the-Fezz described, over ten years ago.
Patent US5140641 - Servo valve loudspeaker - Google Patents
Patent US5140641 - Servo valve loudspeaker - Google Patents
Hi,
You can't horn load low bass without a truly huge horn.
I fail to see how a driver can modulate the air flow,
nevermind linearly, and with low generated noise.
rgds, sreten.
Sreten,
In_the_case_of_bass_below_40hz_or_so_coupling_to_the_air_becomes_an_issue.
Horns_solve_this_by_impedance_matching_along_their_flare.
The_brute_force_method_is_multiple_drivers,however_it_does_become_cumbersome.
As_stated_in_the_article_the_trw_carves_off_airflow_to_the_spinning_blade,which_as_frequency_halves_its_efficency_doubles,and_leaves_frequency_modulation_to_the_voicecoil_driven_blade_modulation.
So_you_understand_the_flat_piston_of_a_driver_excells_at_coupling_to_about_30-0hz.
Below_that_it_falls_in_efficency_to_rapidly.
Perhaps_we_agree_more_than_first_thought?
In_the_case_of_bass_below_40hz_or_so_coupling_to_the_air_becomes_an_issue.
Horns_solve_this_by_impedance_matching_along_their_flare.
The_brute_force_method_is_multiple_drivers,however_it_does_become_cumbersome.
As_stated_in_the_article_the_trw_carves_off_airflow_to_the_spinning_blade,which_as_frequency_halves_its_efficency_doubles,and_leaves_frequency_modulation_to_the_voicecoil_driven_blade_modulation.
So_you_understand_the_flat_piston_of_a_driver_excells_at_coupling_to_about_30-0hz.
Below_that_it_falls_in_efficency_to_rapidly.
Perhaps_we_agree_more_than_first_thought?
Just for giggles, I pasted all of it into a text file and it is 61 pages long, Libre office writer finds 41846 words (259014 Bytes as plain text). I would say this "review" is at least 20 times longer than it needs to be. Is it any wonder that it is self-published?
Hi,
And in about 5 pages with diagrams I could say about
ten times more useful information about its actual use.
rgds, sreten.
While_I_agree_the_review_is_verbose_i_believe_it_is_so_because_it_makes_an_exceptional_claim.
It_then_goes_on_to_provide_detailed_ev4idence_to_support_that_claim.
If_you_deny_the_claim,then_you_need_to_back_up_your_denial_with_evidence.
Most_product_reviews_are_drastically_shorter_because_they_do_not_make_any_such_claim,only_point_out_the_merit_or_fault_of_a_product_vs._similar_product_in_its_category.
I_wonder_which_offends_you_more,_the_wordiness_or_the_claim?
As_for_"kneeling...",_I_have_respect_for_the_length_to_which_the_author_went_to_substantiate_his_claim,_if_the_TRW_were_conventional_perhaps_the_rev4iew_would_have_suited_you_better.
The_article_does_explain_in_great_detail_some_fundamental_aspects_and_foibles_to_optimal_low_frequency_production._If_i_dont_mistake_it_the_author_even_mentions_the_frequency_limit_and_the_fact_that_above_that_limit_cone_based_driv4ers_easily_out_perform_the_TRW.
It_then_goes_on_to_provide_detailed_ev4idence_to_support_that_claim.
If_you_deny_the_claim,then_you_need_to_back_up_your_denial_with_evidence.
Most_product_reviews_are_drastically_shorter_because_they_do_not_make_any_such_claim,only_point_out_the_merit_or_fault_of_a_product_vs._similar_product_in_its_category.
I_wonder_which_offends_you_more,_the_wordiness_or_the_claim?
As_for_"kneeling...",_I_have_respect_for_the_length_to_which_the_author_went_to_substantiate_his_claim,_if_the_TRW_were_conventional_perhaps_the_rev4iew_would_have_suited_you_better.
The_article_does_explain_in_great_detail_some_fundamental_aspects_and_foibles_to_optimal_low_frequency_production._If_i_dont_mistake_it_the_author_even_mentions_the_frequency_limit_and_the_fact_that_above_that_limit_cone_based_driv4ers_easily_out_perform_the_TRW.
Hi,
Read this as someone being an utter pain in
the *rs* should be the title of this thread.
The wordiness in just the stupid assumption
if you repeat it enough it starts to sounds right,
especially if you mix up nonsense with truth.
There is nothing in the article original, stuff
that informed people don't already know,
the rest is is just tedious utter b*ll*cks.
40,000 words that impart a p*ss poor
amount of information to the reader.
Yes, below 20Hz its great, if you can acommodate
it and have the cash to spend. Is it needed ? No.
rgds, sreten.
Read this as someone being an utter pain in
the *rs* should be the title of this thread.
The wordiness in just the stupid assumption
if you repeat it enough it starts to sounds right,
especially if you mix up nonsense with truth.
There is nothing in the article original, stuff
that informed people don't already know,
the rest is is just tedious utter b*ll*cks.
40,000 words that impart a p*ss poor
amount of information to the reader.
Yes, below 20Hz its great, if you can acommodate
it and have the cash to spend. Is it needed ? No.
rgds, sreten.
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Hi,
Your a lost pedantic cause, you don't want to find any
wrong with shedloads of sh*t, given I've already said
its what is not said and what is missing is the problem.
And that is shedloads in terms of real comprehension.
The article in a sense invites you to be a complete bigot. So
far your doing it hook, line and sinker, are you that stupid ?
rgds, sreten.
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Thanks Don,
Not exactly what I visualised, but close enough
I wouldn't physically use horns - no need; already pressurising the driver(s). I wouldn't worry about linearity either, just eq it. For this kind of money, you're well into "build another room next door" territory to accomodate all the paraphanalia including a mega-labyrinth to curtail the noise. WTH, you can have a labyrinth before and after the compression chamber: kill everything over 20Hz and we won't be bothered by noise
I still stand by my earlier comments though - I can't see any justification for going <16Hz. If you want to experience the effect of going deeper, you'd probably get better results strapping solenoids to your chair or something - I think that's been done before too: less likely to set off car alarms etc, and you don't need a cathedral sized listening room
Bits from the earlier thread I mentioned:
http://www.diyaudio.com/forums/subwoofers/67028-fan-subwoofer-7.html#post762789
http://www.diyaudio.com/forums/subwoofers/67028-fan-subwoofer-14.html#post1083551
Reading in, the simplest way to do this is to attach a suitable valve to a solenoid (for linear travel) or servo (rotary travel), and blast a humongous amount of air through - essentially Mr. Danbys idea.
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