Cheap fun with 3ГДШ-2

  • Автор темы Max H

Max H

Местный
Last year I posted a question about speaker arrays, and got a number of good responses. After some time, I have completed my project ;)

I measured one 3гдш-2 and got

Qts = 1.12
Fs = 145Hz
Vas = 0.46l

Not too happy with the Fs, considering the spec says 100Hz, but you take what you get. According to computer simulation using the measured T/S parameters, I should have decent response down to about 75 - 80 Hz in a ported enclosure. Don't take those measured values to the bank, as I am using very old and likely out of calibration equipment, (1950s ex-army signal generator, 1960s VTVM), however I think it's close.

The finished project consists of two narrow 6l columns, each with 3 4 ohm
3ГДШ-2's arranged vertically. The speakers are connected in series. The cabinets are made of 5/8" chip board, and have a 1" diameter port in the rear. I covered them in "cherry" coloured plastic contact paper.

Vocals sound natural, bass is a bit lacking, however it does exist. They go very loud with very little power, and work well on the 16 ohm tap of my output transformers. I intend to borrow a spectrum analyzer from work and find out how they measure.. maybe some improvements can be made by tuning the enclosures better.

Conclusion - for the (very low) price, the 3ГДШ-2 is a nice sounding speaker.

P.S. sorry for writing in English, feel free to reply in Russian.
 

Alio

Местный
I think Fs will changing after couple of weeks. I've got another speaker, but using 5ГДШ-3-8
http://img85.imageshack.us/img85/5292/3gdsh27iq.jpg
First it was with 3ГДШ than I change them to 5ГДШ and think that the last is better.
I try to coat the centre of membrane with vinyl dissolved in acetone. The result is nice to me, high frequency is now beter аnd more equally. Again, I coat edges of membrane by castor oil =). Very nice again, sound became more equally at the middle.
 

Ал.Д.

Местный
И 3ГДШ, и 5ГДШ созданы для открытого оформления (open
baffle). Тонкий бумажный (thin paper) диффузор - главное достоинство, ктр желательно сохранить (not to spoil).
 

Vikt0r

Местный
P.S. sorry for writing in English, feel free to reply in Russian.

Very interesting article, indeed, and maybe a lot more people get a chance to share your fun and knowledge if you take a minute and have an overview look at the forum, and realize that it's a forum using RUSSIAN language before the moderator will remind you to take a look at the Rules -> https://audioportal.su/forums/announcement.php?f=38&a=3 .
So, feel free to make no difference to others ;)
 

Max H

Местный
Alio - your enclosure is much larger than mine, per speaker. The distributed ports reminds me of the designs in the back of old GE (USA) tube manuals. Have you made any attempts to measure frequency response, before and after modifications? (don't take that design down, I want to save it to my home computer tonight!)

Ал.Д. - original plan was open baffle, but it is simply too large to work properly in my environment. The ported enclosure was motivated by reasons not connected to my desire for good sound, which occured after I had bought the speakers!

Vikt0r - If I could understand Russian so well, I would have obviously read the rules -- that said, I am taking Russian lessons now, and what looked like Chinese 6 months ago, I am beginning to understand. I have a cyrillic keyboard at home, and I will use it in the future, however I hope there is not a rule about poor grammar! Of course it would be easier to post on one of the english forums, but this website is really interesting, and I find it a better match for my interests, despite language. It's also a good opportunity to practice reading (and in the short future, writing) Russian.
 

Vikt0r

Местный
No probs, but only some of us (probably very few of us) would be able to understand - so better don't hesitate to use russian EVEN with poor grammar - it is really highly appreciated over here and you will get tremendous help in that case. Neither my native is russian (need to note that I speak it perfectly though :) ), but I really enjoy communication happening here - so it's worth of learning, definitely!
But I think you would need at least to warn the moderator (leave a personal message for Tommy ) in order to get tolerated with pure English.

Anyway, welcome! Good to see you here!
 

Vikt0r

Местный
Don't take those measured values to the bank, as I am using very old and likely out of calibration equipment, (1950s ex-army signal generator, 1960s VTVM), however I think it's close.

I would not suggest trusting too much to them. Rather I would suggest using a piece of software called JBL SpeakerShop along with a simple DIY add-on device to your PC's soundcard (article you can find here -> http://www.bluesmobil.com/shikhman/arts/box.htm ) literally called "the tiny box" - this gives you very exact, detailed and visible analysis of TS parameters, and also some fun with constructing the "tiny box". The program can also help to select and optimize the acoustic enclosure for your particular speaker.

Requires some effort, not the easiest way, but worth to go for. In case if you want it the serious way. The attracting point here is that, if youv'e got some really good speakers, you can get from them just the best they can offer.
And, what Ал.Д. was trying to mention - is that these particular speakers have too high Qts for vented box or sealed box, the suitable acoustic enclosure for them is the open baffle. The main advantage which makes the essence of these speakers - is the thin paper cone. These speakers are the ultimate solution for middle driver (100-150 Hz to 10-12 kHz)
in tri-wiring(amping) systems IF you want to achieve full range coverage (20-20000), OR another way - using them as a single sound reproduction unit along with a low-power valve SE zero NFB triode amplifier :D (and similar.. :) ) - accepting and closing your eyes over narrow bandwidth, but ENJOYING the naturality of vocals and acoustic instruments.
 

Ал.Д.

Местный
Лучше и не скажешь:

another way - using them as a single sound reproduction unit along with a low-power valve SE zero NFB triode amplifier (and similar.. ) - accepting and closing your eyes over narrow bandwidth, but ENJOYING the naturality of vocals and acoustic instruments.

Для этого их и делали.
 

Alio

Местный
Max H:
Unfortunately, I don't measure it. But hearing specific changes with sound after couple of weeks.
I've got 4 pairs of this speakers (1 pair 3ГДШ and 3 pairs 5ГДШ) in this box - all of them changes their sound very well.

Ал.Д.
Вы считаете не стоит пропитывать эти головки ничем?...
 

Max H

Местный
Здравствулте!!

Здесь диаграмма частоты откликов, котор я сделал моей системы вчера вечером.

Микрофон был 2m перед громкоговорителем, и спектральным анализатором, Quest SoundPro SE/DL. Шум очень низкой частотности от моей печи, вас может доверить результатам над около 50Hz.


 

Vikt0r

Местный
Здравствулте!!

Здесь диаграмма частоты откликов, котор я сделал моей системы вчера вечером.

Микрофон был 2m перед громкоговорителем, и спектральным анализатором, Quest SoundPro SE/DL. Шум очень низкой частотности от моей печи, вас может доверить результатам над около 50Hz.



HUGE respect for your russian effort! :beer:
What type of enclosure was used during the measurement?
 

Max H

Местный
Спасибо каждое за вашу консультацию!

Коробка используемая для измерений описана в моем первом сообщении. Здесь фотоие принятые от фронта, и задняя часть.





В виду того что я принимал фотоих, здесь мой усилитель 2A3. Я построил этот усилитель в весне, 2006. Этот усилитель был моей мотивировкой для систем громкоговорителя.





 

Alio

Местный
Max H:
Музыкальный комплект =))... Здорово!
Так и планируете с этими АС на 5ГДШ использовать пока?


Что касается пропитки головок.
Купил еще пару 5ГДШ. Поработали они денек. Сравнил сейчас пропитанные и нет.

Хм. Если честно, сказать что лучше - затрудняюсь
Пропитанный касторовым маслом (подвес) и винилом в ацетоне (пылезащитный колпачок) динамик играет поярче и собраннее.
Непропитанный - тепло, мягко, уютно. Больше баса. Натуральнее - особенно голос подается естественнее. Но звук расхлябанный какой-то, бас особенно. Надо корпус перенастроить - но этого и следовало ожидать от мягкой бумаги.

В общем на любителя пропитка. Я пожалуй пока без нее послушаю.
 

Ал.Д.

Местный
Тепло, мягко, уютно - хорошо сказано.
5ГДШ=3ГД, но больше 1Вт на него подавать не нужно.
 

vic57

Местный
Молодец- Max! Этот путь правильный. Пластинка ждет тебя в Минске.
 

Max H

Местный
Vic57 - спасибо!! Я возбужен о моих планах каникулы

Alio - Я буду держать 3гдш-2, однако, я планирую экспериментировать с коробками. Этот викэнд я не одолжил превосходному quest SE/DL, но следующая неделя возобновит работу.
 

vic57

Местный
Минск- приветливый город. Пиши о планах в личный почтовый ящик.
 

Max H

Местный
Мы имели множество дождя последн здесь. Смотрящ мои русские громкоговорители сидя в угле, я думал будет временем сделать что-то с ими.

Я построил экземпляр переговорного устройства Alio's, как описано выше. Они звучают очень более лучше чем моя конструкция. Один громкоговоритель звучает очень более лучше чем 3 в моей конструкции, слишком. Я предназначаю попытаться его обработки конуса в близком будующем.
 

ZugDuk

Местный
Max H
Сделал ли ты ПАС (куча отверстий в задней стенке) как у Alio ?
 
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