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A Tale of Two Ohms - Buying Speakers


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#1 MarkSLR

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Posted 05 January 2012 - 08:17 PM

I bought a pair of T1030 speakers for my system I am building. I get around to hook them up after a while and discover they are different. One is 8 ohm and one is 4 ohm. Did I waste my money? Will they work together with an 8 ohm amp.

Boston Accoustics T930 Series II
Boston Accoustics T1030 3 pair
JBL L100T3

JBL L20T3
KEF Model 103.2
Sony SS-M7a

Harmon Kardon Citation 7.1 amp

Parasound Halo Pre-Amp

Technics 1200 MKII

 


#2 saad

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Posted 08 January 2012 - 10:21 AM

It will affect the amp and the final output of sound. If your amp ranges from 4 to 8/16 ohms in that case - L / R 4ohms will be using more current & power. mix up is never good.

#3 Gerry S

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Posted 09 January 2012 - 09:35 PM

I designed BOTH the T1030 and the smaller and the less expensive T 930. I'm confused about your question ! Have you actually LISTENED to the T1030 as a stereo pair ? They should sound virtually identical when you listen to one compaired to the other. To do this, follow the procedure below.

Place each speakers next to each other as close as possible to minimize room effects. Put your amplifier or reciever in "mono" to insure both speakers are receiving the same signal, then compare the two for similar sonic characteristics.You can then compare the sound of the two speakers by using the balance control. Alternately,use the Speaker A / Speaker B selector switch (if you have one) but make sure both speakers are connected to the same channel (left or right; NOT left and right). Caution: DON'T switch to both speaker A and Speaker B. You can damage the amplifier and/or speakers if you are not careful about playback levels.

Instead, switch carefully between A OR B !

The T1030 has a minumum impedance of 4 ohms at bass frequencies (where it draws the lowest current from the two woofers). The nominal (average) impedance is approximately 8 ohms. Depending on the date each speaker was manufactured, the label located on the back may say either 8 ohms OR 4 ohms. Regardless of what the label or specs says, the speakers should be virtually identical in sound.

I'm assuming that you are NOT using a T1030 for one channel and a T930 for the other (which is a definate no-no).

The T1030 uses two 8" woofers that has a low impedance (around 4 ohms) at bass frequencies. The T930, while similar in design and performance , uses a single 10 inch woofer in a smaller cabinet (to make it more affordable for those wishing performance approaching the larger and more expensive T1030).

The lowest impedance of the T930 is not as low (closer to 8 ohms) as the T1030 at bass frequencies (closer to 4 ohms). If either model is set up properly (not a given) or damaged, they are definately NOT a "rip off". Both are considered "high end bargains" by many experienced audiophiles.

Gerry S

#4 MarkSLR

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Posted 14 January 2012 - 04:04 PM

Gerry S,
Thanks for your help in this matter. Let me start from the beginning so we are all on the same page. I am a novice and am buying quality speakers when I can find them for my new hobby and listening pleasure. I have started this quest since September. I have a pair of BA T930 Series II both labled 8 ohm on tag and have serial numbers that are sequential. I bought a pair of T1030's from a person that had 2 pair and had sold a pair already a year before me buying from him. As I was taking the speakers out of the truck there was an 8 ohm sticker tag at the bottom of one T1030 and a 4 ohm sticker tag on the bottom (underneath) the other speaker. That is why I am asking for guidance. My amp I have to test them is an 8 ohm. I have not hooked anything up to test. I will follow your instructions. I am heading to Florida but will test in 2 weeks. I have to check and see if the serial numbers are sequential ( I was excited and in a hurry and did not do this when I paid for them), I would hope they are. Thank you very much for your help. I do not want to damage anything if I can avoid it.

I want to have them set up so I can play my music loud and clear.

The sticky ohm tags being different ohm values on each of the T1030 speakers concerned me,

I am a huge fan of 80's and 90's Boston Accoustics speakers. My rich friends had them in high school ( A70's and A150's) I was not able to afford them. Now it is my turn...


Mark

Boston Accoustics T930 Series II
Boston Accoustics T1030 3 pair
JBL L100T3

JBL L20T3
KEF Model 103.2
Sony SS-M7a

Harmon Kardon Citation 7.1 amp

Parasound Halo Pre-Amp

Technics 1200 MKII

 


#5 Gerry S

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Posted 26 January 2012 - 08:26 PM

Embellishing on my previous post, the way to go if you want to play your music "loud and clear" WITHOUT damaging your main speakers: DEFINATELY go with an external subwoofer. The "ideal" way (added cost & complexity not withstanding) is using a powered subwoofer with "seperates" (pre-amp, electronic crossover, and addtional power amplifier).This "seperates" approach using the "external electronic crossover" limits very low bass frequencies reaching the electronics driving the main speakers, thereby relieving both electronics and the "main" speakers from working "too hard". What available power you have in your "main" eletronics (i.e amplifier/reciever) can be dedicated to reproducing frequencies from the middle bass on upwards (where even most "8 ohm" receivers or amplifiers should have little difficulty with).

If this "external electronic crossover" option isn't feasible, simply adding a "powered subwoofer" is amost as good. Using the "powered sub" approach, the main system STILL won't have to work as hard (the "power hungry bass" is augmented by the "powered subwoofer"). It's in the bass region where most "8 ohm nominal" systems can reach 4 ohms or less, taxing MOST quality but "moderately priced" electronics (recievers, integrated amplifiers).

Adding a "powered sub" means you don't have to "turn up the volume" on the "main system" to get the "punch" many "bass freaks" want. Instead, adjust the "powered subwoofer" level control to accomplish this.You can even TURN DOWN the bass control of your primary reciever/amplifier and obtain even cleaner and louder sound from the mid-bass up.

"Loud and Clear" is primarily subjective; you may be able to reach these goals with the equipment you already own. It's not what you have (including room size and acoustical proprties) but how you use it.

#6 MarkSLR

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Posted 11 March 2012 - 10:08 PM

The test results displayed the 8 ohm speaker producing noticebly more volume compared to the 4 ohm speaker at the same power level. I am going try and find a matched set of the T1030's. The serial numbers are significantly different (eons). The sound quality is very nice except for the unmatched volume. I will have to power each one separately. I am only using about 40 watts max in this room I am using.

Boston Accoustics T930 Series II
Boston Accoustics T1030 3 pair
JBL L100T3

JBL L20T3
KEF Model 103.2
Sony SS-M7a

Harmon Kardon Citation 7.1 amp

Parasound Halo Pre-Amp

Technics 1200 MKII

 


#7 Gerry S

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Posted 02 April 2012 - 03:20 PM

During the entire T1030 production run (think it was 2 -3years ), there was NO changes made to this system. It's possible (even likely) the foam surrounds have rotted away. If true, this will make the bass sound weaker and "less loud" compared to the unit that's fully restored/refurbished. There are kits available to replace these surrounds.

Also the possibility that previous owners experimented with the crossover and screwed it up, or that the electronics in the playback chain is bad in one channel.

#8 MarkSLR

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Posted 28 October 2013 - 05:35 PM

Just bought a matched pair of T1030's and they are awesome!  It was worth waiting for a quality speaker in the walnut finish.


Boston Accoustics T930 Series II
Boston Accoustics T1030 3 pair
JBL L100T3

JBL L20T3
KEF Model 103.2
Sony SS-M7a

Harmon Kardon Citation 7.1 amp

Parasound Halo Pre-Amp

Technics 1200 MKII

 


#9 MarkSLR

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Posted 13 November 2013 - 03:13 AM

So The last pair I bought are 4 ohm T1030.   I have (3) 8 ohm and (3) 4 ohm. T 1030's.  I will use the 3rd speaker for the center channel in two separate systems.


Boston Accoustics T930 Series II
Boston Accoustics T1030 3 pair
JBL L100T3

JBL L20T3
KEF Model 103.2
Sony SS-M7a

Harmon Kardon Citation 7.1 amp

Parasound Halo Pre-Amp

Technics 1200 MKII

 


#10 Gerry S

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Posted 02 December 2013 - 01:24 AM

To the best of my knowledge, there was/is just one version of the T1030. The different "labeling" may reflect a marketing decision.

 

To elaborate, it is "4 ohms" at low frequencies (the power hungry frequencies), but a "nominal" 8 ohms over the rest of the range. Many (most?) speakers have this characteristic. If you look at a "impedance curve" of  just about ANY given loudspeaker, it varies with frequency...not just a "single number".






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