Ohm Acoustics Model i (Sub Bass Activator Install (w/ pictures))

[MetalDaze]

Hey Metaldaze, a fellow i owner here. Great to see the enthusiasm for these great speakers. I find that mine give plenty of clear deep bass without the need for the activator, but I think that is because of my room, but you have gotten my curiosity up now.

I just want to add one thing, I have a lot of respect for Ohm acoustics. John and Evan have picked up the phone when I called, and answered my questions with genuine interest and sincerity. I even got some troubleshooting advice for free. Those that don't want to take on a repair themselves, I applaud you for sending the speaker to Brooklyn for repair, or ordering replacement items and keeping these guys going.
I have never tried calling JBL and asking to speak with their resident audio engineer to discuss some aspects of my L7's. But if I did, I doubt that any conversation happen, but i could be wrong.

Ditto! I also very much like your signature. That represents my mantra too.

They certainly have gobs of low end. Speaker/listener placement will play a large roll as you say in perception of low end response. All my other conventional speakers from Ohm (3 H's, C2's pair, I pair) all have the activator updates. I did it partly to complete the 'restoration'. But also because, at times, I like to push the limits and listen quite loud. And since these can take so much power, It seemed smart to get them.

I also have observed non linear woofer motion on them without the activator. And that happened with both my turntable, and digital. I do not run them with a high pass filter so that is why. But I was surprised to see it happening on digital music. Specifically the song "Cars" by Gary Numan ; The 24bit version of the album 'The Pleasure Principle'. The subwoofer w/o the activator would do all types of high excursion, non linear (inaudible) movements as it tries to reproduce frequencies well outside of it's reproductive limits.

Sonically, the "aye's" did not need the activators. But mechanically, it was obvious in my set up - the subwoofers would benefit and dare I say, required the electrical dampening of the SBA's. Since the install, all non linear woofer motion has been eliminated at any volume. With any source content.

Lastly and subjectively, I noticed a bit more texture to the bass after the install. Complicated bass line passages where certain parts would be muddy and it was difficult to hear exactly what the bass line was playing - became easier to hear in the presentation. There was also a small increase in "impact or slam" with modern loudly mastered music.

My midbass woofers already had the activators installed when I updated them. So when I installed the SBA's on the sub woofer, the whole musical display sounded more interwoven, and connected. As if to say I was more aware there was a separate subwoofer playing along with a mid bass woofer prior. And after the subwoofer SBA the sound became more singularly bodied.

If it ain't broke, don't fix it But keep an eye on those subs for large linear excursions with no sound heard.

 

[Old Guy8]

Congrats on your updated "i"s.
I've a lovely pair of C2s I bought in '77. Had John upgrade the woofers with poly cones and SBA in '15. There was a snafu with the first pair of woods. They replaced them, including shipping costs. I had no customer service complaints.
I recapped with Dayton film caps.
Currently sounding great, driven by a 300b amp with just 7.6 watts.

 

[Diamond Blue]

Congrats on your updated "i"s.
I've a lovely pair of C2s I bought in '77. Had John upgrade the woofers with poly cones and SBA in '15. There was a snafu with the first pair of woods. They replaced them, including shipping costs. I had no customer service complaints.
I recapped with Dayton film caps.
Currently sounding great, driven by a 300b amp with just 7.6 watts.

Did they sound better/different after you recapped them? I have been researching that for the Ohm N, I can only imagine how nice it is with the 300B amp

 

[Old Guy8]

Did they sound better/different after you recapped them? I have been researching that for the Ohm N, I can only imagine how nice it is with the 300B amp

Yes, I think they do after recap. A favorite speaker for me.
I can't attest to improvement from woofer upgrade.

The 300b is power limited. And bass doesn't have as much force behind it. But, it has quite a holographic presentation.

Is the Ohm N a misprint? Never hear of that model.

 

[MetalDaze]

Yes, I think they do after recap. A favorite speaker for me.
I can't attest to improvement from woofer upgrade.

The 300b is power limited. And bass doesn't have as much force behind it. But, it has quite a holographic presentation.

Is the Ohm N a misprint? Never hear of that model.

I believe I have seen the pictures of your C2's with the poly woofer. I have always liked how they look with them installed. They look like a more 'I mean business" type of speaker with them. With the original woofers, they were more unassuming - until you played music through them. I had a pair of C2's with the poly woofer update, but I sold them due to life changes. I still have another pair which has been fully rebuilt by Ohm. All original still with the same woofer, just redone nicely. Doped the cone and a new surround along with the SBA's and crossover inspection.

I auditioned them in my main listening room against the poly cone C2's. And while the sound was so very similar. I found the C2's with the completely rebuilt woofer to sound a bit more natural. The poly cone was still very natural sounding, but It had more clarity in the upper mid bass. Not a bad thing, I just preferred the sound of the other set I had. And honestly if I didn't have both at the same time in the same room, hooked up to the same system. I wouldn't have known the difference.

Here is a picture of the ridiculous experiment I had going in an old place I lived. I was using them like stacked advents. Although the bass was powerful coupling the two woofers together in this configuration. The sound was much better when I changed them to be "tweeter to tweeter".

This experiment was short lived as I soon learned how to get the sound I wanted without resorting to mad science hour tactics.
But in the picture you can see the poly cone woofer on top, and the rebuilt one on bottom.

As for the Ohm N - no that wasn't a misprint. It was Ohm's very first stand alone subwoofer.
If you look in the literature, Ohm states their very first subwoofer ever is incorporated into the "i". The Ohm N, and subsequently the N2 was a stand alone subwoofer which accompanied their smaller satellite type speakers. Which were in a Metal housing, low impedance at 4ohms and went fairly loud for their size.

A later change to the N subwoofer, which was dubbed the N2 came when they replaced the dual 12" passive radiators for ports.

In all my searches on the web, I've only found a couple of these advertised for sale. And the AD's have been long expired.
The specifications for these are nothing special. Something like a simple DIY could probably stomp it. But it's the collectability and furniture grade vintage cabinet finish which would make it blend seamlessly into anyone's home, whom already owns Ohm speakers.

They have made other subwoofers since these. Largely unattractive looking things sold with their Sat/Sub combinations from the 90's and early 2000's. According to Ohm's website, they are currently making a new subwoofer ready for release sometime soon. It's called the "SB-212".

If you read their description, It's basically and SVS type offering using a larger enclosure and ICE power modules. With KEF's latest "uni-core dual concentric" driver design. Of course they will advertise and perhaps trademark it as something similar, but with enough difference to avoid litigation.

 

[Old Guy8]

I believe I have seen the pictures of your C2's with the poly woofer. I have always liked how they look with them installed. They look like a more 'I mean business" type of speaker with them. With the original woofers, they were more unassuming - until you played music through them. I had a pair of C2's with the poly woofer update, but I sold them due to life changes. I still have another pair which has been fully rebuilt by Ohm. All original still with the same woofer, just redone nicely. Doped the cone and a new surround along with the SBA's and crossover inspection.

I auditioned them in my main listening room against the poly cone C2's. And while the sound was so very similar. I found the C2's with the completely rebuilt woofer to sound a bit more natural. The poly cone was still very natural sounding, but It had more clarity in the upper mid bass. Not a bad thing, I just preferred the sound of the other set I had. And honestly if I didn't have both at the same time in the same room, hooked up to the same system. I wouldn't have known the difference.

Here is a picture of the ridiculous experiment I had going in an old place I lived. I was using them like stacked advents. Although the bass was powerful coupling the two woofers together in this configuration. The sound was much better when I changed them to be "tweeter to tweeter".

This experiment was short lived as I soon learned how to get the sound I wanted without resorting to mad science hour tactics.
But in the picture you can see the poly cone woofer on top, and the rebuilt one on bottom.

As for the Ohm N - no that wasn't a misprint. It was Ohm's very first stand alone subwoofer.
If you look in the literature, Ohm states their very first subwoofer ever is incorporated into the "i". The Ohm N, and subsequently the N2 was a stand alone subwoofer which accompanied their smaller satellite type speakers. Which were in a Metal housing, low impedance at 4ohms and went fairly loud for their size.

A later change to the N subwoofer, which was dubbed the N2 came when they replaced the dual 12" passive radiators for ports.

In all my searches on the web, I've only found a couple of these advertised for sale. And the AD's have been long expired.
The specifications for these are nothing special. Something like a simple DIY could probably stomp it. But it's the collectability and furniture grade vintage cabinet finish which would make it blend seamlessly into anyone's home, whom already owns Ohm speakers.

They have made other subwoofers since these. Largely unattractive looking things sold with their Sat/Sub combinations from the 90's and early 2000's. According to Ohm's website, they are currently making a new subwoofer ready for release sometime soon. It's called the "SB-212".

If you read their description, It's basically and SVS type offering using a larger enclosure and ICE power modules. With KEF's latest "uni-core dual concentric" driver design. Of course they will advertise and perhaps trademark it as something similar, but with enough difference to avoid litigation.

Last time I looked at subs on thier site. I think they said, were adding veneer to bought Chinese subs. Veneer choices to match customers Ohm Walsh speakers.
I remember John S. writing to me about difference of poly/SBA woofers, would likely make. He thought they would improve sound in the female vocal range. I had no way to compare paper to poly sound. So thanks for your experience.
My audio memory is gone within a minute. Effect of Updates I've made to speakers through recaps have been very subtle. Unless something wrong with old caps. I usually just decide afterwards if I still like the sound. If so, was a success.

Back in '77, when I bought the C2s. I auditioned the model H also. They had deeper bass, is impression I remember. But were above my budget, I believe. I long time ago, so not sure. Local Appletree Stereo store also had the model F. They liked to demo them, as your shopping for records. Now, they had some impact bass!

Still have a sales brochure left from then. A couple pages above. Time passes.

 

[MetalDaze]

That sounds about right regarding the subs. At least they are marketing offerings which will match a set of Ohms one may already have. Regardless of where the tech originated from.

I agree about the crossover/cap components too. Unless there is something wrong, or if a value is different from the one being changed. There really should only be an extremely subtle, to no difference in the sound.

I concur & my audio memory I believe is no better than anyone else. In this particular situation I recall making a mental note which wound up sticking with me. I had to choose which ones to keep and which ones to sell. I guess it was the rational behind the decision making process more so than anything.

And yes your memory serves you correct The H's do go about 1 octave lower than the C2's, and are extremely tight and articulate with their passive radiator. I have 3 that I use across the front of my 2.1/5.1 system as L-C-R, C2's on rear. But since I got the "ayes" it's been 2.1 for quite some time now. Still with the C2's on rear channel duty for 4.1.

I love seeing and reading vintage literature about this stuff from a bygone era. I was not alive then, but It transports my mind there. Thank you for the uploads

 

[stephenB1]

I believe I have seen the pictures of your C2's with the poly woofer. I have always liked how they look with them installed. They look like a more 'I mean business" type of speaker with them. With the original woofers, they were more unassuming - until you played music through them. I had a pair of C2's with the poly woofer update, but I sold them due to life changes. I still have another pair which has been fully rebuilt by Ohm. All original still with the same woofer, just redone nicely. Doped the cone and a new surround along with the SBA's and crossover inspection.

I auditioned them in my main listening room against the poly cone C2's. And while the sound was so very similar. I found the C2's with the completely rebuilt woofer to sound a bit more natural. The poly cone was still very natural sounding, but It had more clarity in the upper mid bass. Not a bad thing, I just preferred the sound of the other set I had. And honestly if I didn't have both at the same time in the same room, hooked up to the same system. I wouldn't have known the difference.

Here is a picture of the ridiculous experiment I had going in an old place I lived. I was using them like stacked advents. Although the bass was powerful coupling the two woofers together in this configuration. The sound was much better when I changed them to be "tweeter to tweeter".

This experiment was short lived as I soon learned how to get the sound I wanted without resorting to mad science hour tactics.
But in the picture you can see the poly cone woofer on top, and the rebuilt one on bottom.

As for the Ohm N - no that wasn't a misprint. It was Ohm's very first stand alone subwoofer.
If you look in the literature, Ohm states their very first subwoofer ever is incorporated into the "i". The Ohm N, and subsequently the N2 was a stand alone subwoofer which accompanied their smaller satellite type speakers. Which were in a Metal housing, low impedance at 4ohms and went fairly loud for their size.

A later change to the N subwoofer, which was dubbed the N2 came when they replaced the dual 12" passive radiators for ports.

In all my searches on the web, I've only found a couple of these advertised for sale. And the AD's have been long expired.
The specifications for these are nothing special. Something like a simple DIY could probably stomp it. But it's the collectability and furniture grade vintage cabinet finish which would make it blend seamlessly into anyone's home, whom already owns Ohm speakers.

They have made other subwoofers since these. Largely unattractive looking things sold with their Sat/Sub combinations from the 90's and early 2000's. According to Ohm's website, they are currently making a new subwoofer ready for release sometime soon. It's called the "SB-212".

If you read their description, It's basically and SVS type offering using a larger enclosure and ICE power modules. With KEF's latest "uni-core dual concentric" driver design. Of course they will advertise and perhaps trademark it as something similar, but with enough difference to avoid litigation.

 

[stephenB1]

Hello, I like your write-up. I thought that the SBA Woofer Upgrade came with a vent tube adapter to make the bass go lower - did yous come with an adapter? Thank you, Steve

 

[MetalDaze]

Hello, I like your write-up. I thought that the SBA Woofer Upgrade came with a vent tube adapter to make the bass go lower - did yous come with an adapter? Thank you, Steve

Thank you. Happy it was helpful for you!

Mine did not initially come with the vent tube adapters, but the SBA's are advertised to have them included with purchase.

I had to chase down Ohm pretty persistently in order to get mine. Which when received (in my opinion) were terrible. The fitment, and the overall construction of them was very poor and uncharacteristic of Ohm as I know them. I was at my wits end with them at the time and wrote a pretty scathing post here, which turned into a bit of a thing.

Some of this I believe was related to covid, but a lot of my problems began prior to everything going sideways in 2020. They were having staffing issues and were in a transitional period as best I Can tell.

If you get your vent adapters and they fit well please let us know (pictures are always great). They helped my Dad recently with new woofers for his second pair of C2's and were helpful and quick with the turn around.

 

[Old Guy8]

Hello, I like your write-up. I thought that the SBA Woofer Upgrade came with a vent tube adapter to make the bass go lower - did yous come with an adapter? Thank you, Steve

You weren't addressing me. But, I can add my experience with the vent adapters/tubes.
I had my C2 woofers upgraded to poly cones w/ SBA in around 2015. It took two tries by Ohm. First time the voicecoils rubbed. Ohm expedited replacements and included the vent adapters/tubes with second woofers set. I though the purpose of vent adapters / tubes was to reduce any undesirable noise through vent.
Mine fit snugly in vent.

 

[stephenB1]

You weren't addressing me. But, I can add my experience with the vent adapters/tubes.
I had my C2 woofers upgraded to poly cones w/ SBA in around 2015. It took two tries by Ohm. First time the voicecoils rubbed. Ohm expedited replacements and included the vent adapters/tubes with second woofers set. I though the purpose of vent adapters / tubes was to reduce any undesirable noise through vent.
Mine fit snugly in vent.
View attachment 2331770

Thank you. Happy it was helpful for you!

Mine did not initially come with the vent tube adapters, but the SBA's are advertised to have them included with purchase.

I had to chase down Ohm pretty persistently in order to get mine. Which when received (in my opinion) were terrible. The fitment, and the overall construction of them was very poor and uncharacteristic of Ohm as I know them. I was at my wits end with them at the time and wrote a pretty scathing post here, which turned into a bit of a thing.

Some of this I believe was related to covid, but a lot of my problems began prior to everything going sideways in 2020. They were having staffing issues and were in a transitional period as best I Can tell.

If you get your vent adapters and they fit well please let us know (pictures are always great). They helped my Dad recently with new woofers for his second pair of C2's and were helpful and quick with the turn around.

I am just waiting for the new 12 Inch subwoofers W/SBA to arrive. I was offered two choices by OHM: Have the old subwoofers rebuilt and keep the fabric accordian surround or get a newer version of the 12 inch subwoofer that has a rubber surround. Evan said the newer sub with rubber surround handles more power - I decided to go with the new version, but I am conflicted on whether it was the right decision. Is this something they offered you? Obviously I just want them to sound as good as possible. I did not do all the upgrades becuase it would get pretty pricey to completely update them.

 

[MetalDaze]

"I am just waiting for the new 12 Inch subwoofers W/SBA to arrive. I was offered two choices by OHM: Have the old subwoofers rebuilt and keep the fabric accordian surround or get a newer version of the 12 inch subwoofer that has a rubber surround. Evan said the newer sub with rubber surround handles more power - I decided to go with the new version, but I am conflicted on whether it was the right decision. Is this something they offered you? Obviously I just want them to sound as good as possible. I did not do all the upgrades becuase it would get pretty pricey to completely update them."

Yes it was. I chose to keep the original woofers and add the SBA's since I had already spent the coin to update the rest of the drivers. The original woofers are working well (once I rotated them to reverse voice coil sag/rub from 40 years of gravity). I have a bit of an affinity for the original fabric accordion surround. No particular reason aside from originality & aesthetics. And my 3 model H's have the accordion surround on the passive radiators, so it was nice to have continuity between models from the same manufacturer.

I wouldn't be conflicted if I were you. Those new subwoofers will do exactly as Evan said, and probably be more robust against large power delivery events along with dissipating heat better vs the original drivers.

I'm sure they'll kick some serious ass once you get them installed and properly powered!

 

[pch300]

Also a fellow owner, of Walsh speakers. Heard the I's before, around early '80s, in San Diego. It was loud, and clean sounding. Impressive.

The years of gravity took a toll on the F's spider suspension. Wish I still had those speakers.

 

[MetalDaze]

Now in 2021 (albeit largely updated), they are still loud and clean sounding. And impress me with each listen! Their sound is similar to the later larger omni offerings, but being that they use pistonic motion drivers. You get a little 'column A' .. a little 'column B'. But always with plenty of bass and soundstage.

I understand your sentiment. Having heard a newer pair of 5000's a couple years ago, the sound of them never really left my ears. I got a pair of Walsh 2's since which still have the magic. But don't quite do it the same as the larger Walsh style iterations.

I imagine the sound you remember of the F's is similar to my experience ; a visceral sense that the musicians (or band) are somehow in the room with you.

Listening to Pink Floyd on those 5000's, I can only say that it sounded almost as if miniature versions of the band were actually inside each cabinet, playing live right in front of you. The sound was enveloping and palpable.

 

[odcics2]

As long as your happy with them, but pretty sure just about any person with some refoaming experience could have refoamed those woofers at a fraction of ohms costs and possible even local to you!

I refoamed the original drivers and PRs.

 

[odcics2]

Metaldaze Thank you. I found the original owners manual from my Ohm N & M's. The woofers for the N are being redone by Ohm now. And I will post the scans of the manual. Pretty much covers the "I" as well. Also have the sales brochure just before the I and M and N came out. I will get them posted. Sound quality is perfect in my room. Using Mac Mc-30's to power them. Working on Bi-amping them with a Mac 2105 for the woofers. The sound of the speaker is amazing.

I have an Ohm N2 with a pair of M satellites. Any chance of you posting some of your info? Thanks!