Jeffrey Jackson wrote:

........he has listened to Goto's advice quite a bit.. they have very strong thoughts on how to do things... some you will find humorous, others you will agree with... they beleive that electronics don't really matter.. the driver is the primary importance above all others... to them, it is silly to buy expensive electronics if you do not have double drivers on all your horns.. (I do not believe in this, at all) .. they also do not believe in time alignment... I have heard the amazing transformation that time alignment brings, both with digital correction and with physical alignment... Goto says the drivers can just go anywhere.. their philosophy is that a low distortion loudspeaker is the most important thing... double drivers... I am with you on double drivers... I understand that it shortens a horn.. to me, that is usually a bad direction.. length helps with loading.. especially in the lower frequencies... (at high frequencies I tend to like short horns, subjectively)... I also find that double drivers in the mids and up confuse things a bit.. a touch "blurry"... but I must say that I know two people who liked double drivers in the 300 to 1500 range better than single.. do note that both have *large* rooms... also note that Ming'shorn has adequate length at over 8' for a 60Hz flare...

Jeffrey Jackson wrote:

.... the rear chamber and reactance annulling... yes, I know this subject very well... it makes a very audible difference... and deserves our attention... Bell Labs actually published a formula for source impedance with regards to horn impedance.. it was quite enlightening.. they used very high output impedance amps with their horns... and, yes, they had *giant* aluminum diapragmed compression driven bass horns... interesting, no? the throat of Ming's horn is two times 100 mm diameter openings, I believe... I did not build the dual throat adaptor.... the drivers are quite impressive in scale.. the pictures make them seem smaller than life... but I do wish we could have the rear chambers modified for the task, as you pointed out... Goto, as far as I know, does not do this for any of their horns... for each driver they sell a few different size horns.. and no changes to teh driver.........

ygoh wrote:

1.) Why is it that you do not support using teo compression drivers in the same throat?   Is the distortions increases, such as wavefront distortion?

ygoh wrote:

2.) What are the main reasons of using two compression drivers at the same throat, beside shortening the horn's length?

ygoh wrote:

3.) Do you agree that with using shorter (mouth dimensions is unchanged) horn will not decrease the 'loudness' or efficiency, as efficiency does not depend on the length of the horn, but efficiency depends on throat's area and the drivers itself?

ygoh wrote:

4.) Do you also agree that by shortening the horn, you loose lower frequency?  Another word, the lower cut off frequency increases?

ygoh wrote:

1.) What's that formula to calculate the back chamber volume given a throat reactance? 2.) Would it be a bigger back chamber with higher reactance at the throat?   or vice versa?

Romy the Cat wrote:

ygoh wrote: 1.) Why is it that you do not support using teo compression drivers in the same throat?   Is the distortions increases, such as wavefront distortion? Sure the wavefront gets spread; it is what Wilson does in his WAMM system. The drivers are never the same. There are always are small between them, so what you have two drivers, with own necks to drive the same throat it is an opportunity for problems. I do not even go into the discussion how the axes of two drivers face the same not perpendicular throat. Try to angle a single driver from the horn throat or offset their centers – you will see the result. How pretend that you have two 45 degree drivers firing into the same hole.  ygoh wrote: 2.) What are the main reasons of using two compression drivers at the same throat, beside shortening the horn's length? Increase pressures nothing else. Double drivers do not shorten the horn's length – the double size throat does it. The double compression drivers use very commonly in past. Do not forget however that compression drivers in past were only about developing maximum acoustic pressure, there was very little consideration about quality of sound. Put in this way- they were not applied consideration and way less inferior then what he have noonday for home system. So, the RCA, Altec, Klangfilm  and whoever else in past make the stupid double drivers configurations to get more yelps form little amps in order to sound reinforce larger areas…  ygoh wrote: 3.) Do you agree that with using shorter (mouth dimensions is unchanged) horn will not decrease the 'loudness' or efficiency, as efficiency does not depend on the length of the horn, but efficiency depends on throat's area and the drivers itself? Efficiency depends from profile and varies slightly. Efficiency is less important factor. The important one is an equalization at a given frequency or the horn equalization diagraphs. I have no idea what it is not being used  ygoh wrote: 4.) Do you also agree that by shortening the horn, you loose lower frequency?  Another word, the lower cut off frequency increases? Sure, a longer horn means the higher ratio between mouth and throat, means more LF boost and more HF roll off.  ygoh wrote: 1.) What's that formula to calculate the back chamber volume given a throat reactance? 2.) Would it be a bigger back chamber with higher reactance at the throat?   or vice versa?  You do not need any formulas. Use the guideless form this post: Practical Guide for Back Chambers Tuning. The Cat

Thanks, Be, for a correction but the fun part is no one acknowledged your blander. The Goto drivers I think are exotic terra incognito for most people and I think it is how Goto Company is willing to keep it. No one talk about nuts and bolt of Goto compressions driver, trying to convince the parties of interest in Goto’s alleged design advancement. Not one talks about Sound from Goto drivers. I wonder what ideas Goto-Company and Goto-resellers have that would make their driver more popular than they are now. The only exposure that I see from Goto is adolescently-designed installation with system owners too full of themselves to even to cognitively recognize what Sound they are getting out of own playback.

I think if Goto is willing to go somewhere and if Mulg is willing to sale that 56 feet boat on Lake Erie bought for the money of Goto distribution, then those Goto people need to talk a little about themselves and about own products. Avantgarde could press zillion of their horn but the Avantgarde business started what AG’s US distributor opened his month (and Avantgarde ended what he shut up). Ming site should have a lot of context and the site should be interactive. The site should have a lot is service information about horns, frames, crossovers, success stories. Goto should be presented as an equitable competitor to JBL and TAD and the results that Goto demonstrate should be convincing to use them. Goto shells try to sell their driver as EOM to other horn manufactures…  I can go on and on but Goto is not there.

The price for Goto drivers in Japanese catalos is reasonable. The “street price” in Japan is even 30-50% lower. The US prices are in tense thousands that clearly indicate that there is a room for investment into the drivers’ publicity. Perhaps a situation what Goto sell 10 drivers per year is something that Goto feels comfortable but I feel different. My feeling is that until Goto will not be widely available and widely used by more or less civilized users then Goto (as a company) will not learn how to make better drivers. Ming is a new US distributor and let see where he we take Goto. There are some distributors who juts move boxes and there those who do active product development. The time will show where Goto will lend in the hierarchy of horns opportunities.

ygoh wrote:

1.) What's that formula to calculate the back chamber volume given a throat reactance? 2.) Would it be a bigger back chamber with higher reactance at the throat?   or vice versa?

 You do not need any formulas. Use the guideless form this post: Practical Guide for Back Chambers Tuning.

Kcct82 wrote:

On to other things... now that we've been using the GOTO SG505 for a while, the verdict is that it does not sound good below 290hz.

As I understand you use the GOTO SG505 in 150Hz horn and report that it does not sound good below 290Hz. If so then it would be interesting to know what was wrong specifically with sound.

There are only 2 reasons why it does not sound good: problem with horn and problem with driver. You might test them independently buy I do not thing that it is the drivers but rather wrong driver for a wrong horn as I feel that got is kind of damn about it. 

What high-pass filter you use? Although the GOTO’s Ming said that GOTO recommend using first order crossovers but I presume that they begin to do it after reading and learning from this site as few years back.  Formerly GOTO insisted to use 4th order only and it frankly might be for good reasons – theirs drivers are too generic and nonspecific. My perception of proximity of crossover point to the horns’ rates based upon relatively fast opening horns. GOTO horns open very slow and the slow-opening horn might need 1-2 octaves at the bottom in order do not have the “boom”. Here is where the GOTO demands for 4th order came from.  In the following post:

http://www.goodsoundclub.com/GetPost.aspx?PostID=8750

Ming Su, as an official GOTO rep, put GOTO drivers into 1-st order camp. It is very god in my view as the 1-st order is the way how it must  be done but the system shell be designed and thought out initially to be able to work within 1-st order. GOTO were not thinking in context of first order to begin with, the park of their drivers, their horns are a clear indication that GOTO allays were minded about high-order crossovering system. So, what Ming Su said sound sexy for the ears of cogent horn aficionados but it might be not supported by the GOTO products. I do not think that what Ming had any sinister intend. To state that GOTO is “1-order comply” system sounds good (particularly fro the reads of this site), it is might be even something that GOTO people begin to believe in themselves. However, I think that looking in the way in which they sliced the audio range among the drivers and the characteristic of the drivers themselves I presume that they had very high order in their minds.

So, if GOTO SG505 in 150Hz horn does not sound well 290Hz then I would sharpen the filter and to see if it get better. Most likely the slow opening of the GOTO horn with it’s long pipe get too much saturated with extensive for the given profile LF.  It is highly possible that the legend of “slow opening horns has better bass” might derived expectedly from this misperception: people might recognize the choking sound of the slow opening horns as “more bass” from horns.

If you more describe in your own words the specifics of the sound below 290Hz then it would help identify if my assumption is “hot” or “cold”.

To use a Class D amp on those SG-146LD GOTO drivers? Is it what GOTO proposes? Hm, I do not know, the more I learn about them the more question I their sanity. The SG-146LD does not adjustable resonance frequency. It means that in whatever horn it will be used it will have no option to dial the resonance frequency to the given horn reactance. The only one minor way to do so for people on the filed would be to tune the SG-146LD loading to an amp. However, the Class D amps have no sensible loading. They are animals what will drive anything and will push senseless through anything….

About those shaking devises – I truly hate them. I mean I did not hear them, I heard a few similar but I truly hated the concept that I feel is fundamentally faulty. All those “shaking” anticipations are pure inventions of bad marketing and former experiences of bad audio. There are no shaking events in live sound. Did you even have any shaking experiences or body pressure during live music? I do not mean the pop/rock/jazz crap but I mean the live play of musical instilments when sound is created by natural vibration of subject in air. You can listen a 35”organ and you will never feel any body vibration. Never!

In audio the morons build up the atmosphere pressure before then build up tonal pressure and to insult the injuries they now stick in the brains of already fucked audiophiles a dildo of shaking sensation. Wonderful! Let wait until it will make the TAS recommended component of the year…