Series vs Parallel for dual Accuton Woofers

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Hello. I am new to this forum. I have commited myself to building Tony Gee's Humble Statement speaker. I already have the four woofers (C220-T6-220), CAD program is done, wood for the CNC machine is also on the way. I realize some of you are not fond of these drivers, or the speakers. That not withstanding, my Atma-Sphere MA-1 amps will not drive the woofers if they are in parallel, 2.5 Ohm dip.

What are the pros and cons to running the woofers in series. I am in no hurry, so alot of experimentation is fine.

Any advice would be helpful.
 
Re: Why does parallel sound better?.

Cousin Billy said:
Hello. I am new to this forum. I have commited myself to building Tony Gee's Humble Statement speaker. I already have the four woofers (C220-T6-220), CAD program is done, wood for the CNC machine is also on the way. I realize some of you are not fond of these drivers, or the speakers. That not withstanding, my Atma-Sphere MA-1 amps will not drive the woofers if they are in parallel, 2.5 Ohm dip.

amp oscillates?

What are the pros and cons to running the woofers in series. I am in no hurry, so alot of experimentation is fine.

Any advice would be helpful.
series can effect driver Q and thus bass response.
 
I think you have few options-

use 2x 16 ohms c220-t6 , but you will need
a) change values (double capasistance, double less inductance)
b) lower midrange tweeter with voltage divider about 3-4db


second option (perfect which I have tried and using in studio)-
3x 12ohm c220 t6- for my opinion is perfect blend with c173n if amp can drive 4ohm load

third option (also very good , I am using this at home)

4x c220 t6 8ohm in series/paralel. this version do not have such bass slamm as 3x version but it have very friendly load(even 2a3 amp drives it hapily and in realistic bass levels and somewhat more relaxed sound(due big total area) I didnt felt that this version(paralel/series) was inferior comparing to paralel. actualy this version I prefer for clasical works , while 3x 16ohm versions is very punchy with solid state amps

c173n is realy sensitive driver(and accutron neodymium tweeter not caching up it by means of eficienty) 2x 8ohm c220 overlaping with c173n with some amps is not very easy load in higher bass lower midrange..
 
Thank you elviukai

I have a problem.

I already have the two pairs (four in total) of the Znom 6.0 ohm (Re 5.9 ohm) version of the C220-T6-220, 89.6dB.

I was going to run them in series?.

Remember please, I am running Atma-Sphere MA1 OTL tubed amplifiers (135 watts into 4 ohm, 140 watts into 8 ohms, 150 watts into 16 ohms). They like, and make more power, into higher impedence's. The higher the impedence, the better. No solid state amps in my house.

Do you have a solution to running these two drivers per speaker in series with the C173N-T6-90, 93.2 dB mids and the C25N-6-13 92dB tweeters?.

Do you recommend I send them back and get the 11 Ohm versions of this same driver?.

Should I wait and get the C220N-T6-220 Neodymium 93.2 dB woofers?.

I have not yet started cutting my MDF or Baltic Birch Ply. I can change the configuration of the box, i.e. volume. I can accomodate 3 C220's per box, what would my ideal volume be?.

Yes, my amps can drive 4 Ohms (3x 11 Ohms all in parallel), remember again, if I run three 11 ohm woofers in series, my amps will develop even more power.

Ultimately; for a tubed amplifier, do you recommend parallel, or series connection?.

What is the real problem with running woofers in series?. My amplifier manufacturer has told me there is nothing wrong with running drivers in series. Coincident Speaker Technologies run their Pure Reference Speakers with woofers in series.

LOL
Bill
 
Hi

The problem is there probably will be some differences between two identical woofers. If one woofer resonates at a slightly other freq, then it will have a different impedance plot. Putting in series will cause the voltage divide according to the impedance difference. The woofers will be differently loaded that case.
Parallel, they will not interact this way.
 
Hi there,

if you have transformeless amps you would benefit from 16ohms. but you must understand one thing- midrange has eficienty of 92.5-95db you will not cach it up with 2x 8ohms in series. some people think that low sensitivity is only problem for low powered amps. high eficienty speakers(assuming the same xmax .cone and filter topology) sounds better -simply much more "imediatly sounding", lively at low levels, not compressed.luckily later production accuton is drivers did not add dicortion dramaticaly(comparing for example with audiotechnology) with increased input. I think you can use 2 woofers in series(just adapt xover for 16ohm impedance)
and lower midrange tweeter level by 3db(preferable not by voltage divider but by simple resitor in series with your amp) than tony design. so your speakers will be somewhere at 89db.
but still better would be 3x 16ohm with solid state which deliver more current in lower loads

and 4x 8 0hm in series paralel would be my choise for ordinary tube amp with 8ohm output
if you want i can provide some impedanse measurements and sensitivity for all versions i had designed.

another option is to use neodymium verison of c220. it has 2.5db more eficienty in lower midrange than ordinary c220. it would be very good driver because it has musch more sensitive lower midrange which is really issue in tony design. however i found prices of neodymium verison ridiculous, I always choose 2 std magnets versions for almost the same price. I also like to add extra magnet to c220.it provides 0.8-1.2db extra sensitivity in lower midrange and midrange(not in bass)

yes diferent impedanse profiles would split load inequaly but i didnt find that accutoin drivers suplied in pairs have sigificant diferencies(they have mostly the same peak height,only 2-3hz Fs differs sometimes)

one negative thing I noticed when conecting driver sin series- not good sonical result with high inductance(big gap) drivers. otherwise sonicaly diferencies very similar to paraleling
 
yes. I run 8 scan speak 23w4557 subwoofers in array on good mood :) , but still its depends. I like listen music with subs off. sometimes i thinking to add extra 8psc c220 as subs to work up to 50hz . but speakers will be bulky even for my studio not speaking about home enviroment. for me most important range is 80-800hz . room resposne will boost midbass(especialy in smaller rooms) neodymium version has better sensitivity on lower midrange. for midbass c220is better, for lower midrange i like neodymium version litle bit more. but diferencies is minor.
 
OK everyone, here we go.

All the drivers are in.

Humble HomeMade HiFi Humble Statement / Marten Coltrane, clones officially on their way.

I have been in contact with Ram (Ramkuamar) of Audesine. He is a contributor here, and appears to be a very competent enclosure and crossover designer.

Ram sees nothing wrong with running Accuton C220-T6-220 woofers in series. His response was simple; high quality woofers will have very close Fs and impedance curves, it is with less expensive drivers that people get into matching problems. The woofers arrived, as did the mids and tweeters, and as far as I can tell, all drivers are matched at the factory. Knowing many Germans (all my relatives), I believe it.

I spoke with Ralph Karsten of Atma-Sphere Music Systems, the designer/builder of the Atma-Sphere MA1 OTL monoblock amplifiers, he too says series woofers of this quality are easily run in series.

It appears from my first set of calculations that I will have strong base output down to 40Hz, dropping off quickly from there. I do not listen to Organ music, nor am I using the speakers for home theater, so the lowest note naturally reproduced is 26.7hz (I think).

Thank you all for contributing to not only this thread, but others I have started here at diyAudio.

Bill
 
Thank you Dennis

I had Madisound (where I purchased the 8 drivers) do up a LEAP analysis ($40.00). They where given the output impedance of my amplifiers as well as my request for a series connection for the woofers.

They where told to come up with the best fit. I have that information.

I now have Ram, of Audesine, developing ideal box configuration, driver alignment, and spacing. Once completed, he too will develop the crossover.

I will compare those two outcomes, compare it to Tony Gee's findings, build temporary boxes, and start testing. The x-over will be external, so this will be fun.

I believe I have golden ears. I have heard thousands of systems with very few of them giving me goosebumps. I will tweek until these do the same.

Bill
 
Hello Bill
If you go with similar drivers like Tony I would not recommend to go far from his xover. Just attenuate midrange tweeter with 3-4ohm resistor in series and recalculate values of bass components ( 4ohm have 5mH then 8ohm have 10mH and so on)

From my wiew tonys design has to minor flaws whan using with OTL amp.
First – midrange is attenuated (few db)
Second the woofers is 8ohm and paralleled. Its not bad if we connect high current ability amp. System will have good sensitivity but the same eficienty sensitivity . if we connect tony design to tube amp 8ohm tap or amp which not delivers more current in low loads. we will have very lean sounding speakers

I did many experiments with c173n and c220 and system best works down to 50hz –
with 3x 16ohm paralleled (with hefty solid state amp)
with 4x 8ohm in series parallel. (any amp capable 8ohm load)
in both case you will not need attenuate level of midrange. I see you are audiophile and afraid of any extra component. :)



I saw thread where you asked of let play midrange without high pass.
Its possible. In 3 liter closed it has hentle roll off starting from 280hz

If you need steper you can use vent Fb about 150hz after that midrange will not have big overlap with woofers at xover point.

From technical side c173c has very stiff suspension and handles lot of power without too much discortion(it even holds 20hz tone at high spl) It could be driven all way down to 100-80 hz in bigger enclosure and meet woofers in that point. The problem is that c173 has gentle roll of in lower midrange to bass.

If you need nearfield measurements of c173n in 3 liter closed just drop mail.
 
elviukai said:
Hello Bill
If you go with similar drivers like Tony I would not recommend to go far from his xover. Just attenuate midrange tweeter with 3-4ohm resistor in series and recalculate values of bass components ( 4ohm have 5mH then 8ohm have 10mH and so on)

From my wiew tonys design has to minor flaws whan using with OTL amp.
First – midrange is attenuated (few db)
Second the woofers is 8ohm and paralleled. Its not bad if we connect high current ability amp. System will have good sensitivity but the same eficienty sensitivity . if we connect tony design to tube amp 8ohm tap or amp which not delivers more current in low loads. we will have very lean sounding speakers


please read his post. circlotron otl amps of his type are almost perfect current sources, ie. very little change in output due to impedance variation. but all things being equal, he will have more bass control and drive with the higher impedance connection. there is no "tap". just mounds of thermionic triode goodness!

as far as any midrange attenuation (specious, at best) the less resistor in the x-over, the better, IMNSHO.
 
Hello LineArrayNut

It was your posts at AudioAsylum that got me to thinking. I will build a test box for the woofers. I will first cut one hole for a single driver, no correction, then running with successive crossover parts. All will be measured with ARTA.

I will then cut the second hole, and redo all the measurements, series, parallel, with no x-over, and then start adding parts. This is getting exciting.

I will respond with all my findings. I will be unbiased for a single reason, I want the best, and if I have to, I will return the 6 ohm versions and get the 11 ohm ones, and run them in parallel.

Thank you, and elviukai for making me open my mind to alternatives.
 
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