# Boston Acoustics ISTS, 1" Textile Dome Tweeter Kit



## avanti1960 (Sep 24, 2011)

The old standby did not let me down! 

Fist off if you are in the market for a smooth yet detailed 1"soft dome tweeter- run, do not walk, to your computer and order these ASAP because Boston is out of the mobile consumer audio business and these babies are the last of a lot. At 84.99 a pair including flush and surface mounting hardware, wiring with terminal clips and passive crossover (8Khz, 18db) these are literally a hidden gem steal of a deal. 
Granted, the 8Khz crossover and so called "Image System" designation puts these into a niche market but they were exactly what I needed to add some high end to my HAT L3SE widebands. At the -3 attenuation setting their output is only 1db above the HAT driver's sensitivity. I have the L3SEs and the Bostons sharing the high channel on my Pioneer P99. The close sensitivity match at the -3db setting allows me to control them actively as a matched set. 
These are the "kortec" tweeters that come with the Boston SR50 and SR60 component sets. Most reviews are quite favorable of the set- despite the lack of competitive midbass most people have mentioned. Yet almost everyone raved about the tweeters. You know a tweeter must be smooth if people love them when combined with a driver that has anemic midbass in a two-way system. Weak midbass can really bring out any apparent harshness in a tweeter because of the unbalanced sound. 

I first attempted to run the HATs tweeterless but quickly added my old Focal TNB aluminum alloy inverted dome tweeters. At first it sounded excellent but soon I grew weary of the metallic Focal sound and could not satisfactorily tune it out. Some music really exaggerated the nature of the Focal tweeters to the point of harshness while some did sound OK. Despite being off axis the Focals also seemed to exaggerate the static in weak FM radio stations. I would have loved to install my old ScanSpeak tweeters but their format is too large for sail panel mounting and the HATs took their previous upper door factory location. 

After a few hours of listening I am impressed. They seem to offer the perfect balance between smoothness and clarity. The angled surface mounting hardware allowed me to mount them somewhat on axis. It turned out to be the best possible sweet spot. I would actually say that these Boston tweeters sound better on axis than my old ScanSpeak drivers did somewhat off axis- despite being 3X the cost. There is nothing like the sound of a smooth, detailed soft dome! 

I wondered why Boston had abandoned the consumer mobile audio business. If the instructions and design of the mounting hardware that came with this set is any indication it is no wonder. While the drivers are (so far) supremely exquisite in sound quality, the instructions and mounting hardware are just horrible and inexcusable. If I were not a careful DIY'er I would have had a difficult time installing these, and am not surprised they were poor sellers. 
The tweeters have connection terminals that are supposed to "plug in" to the pre-installed and pre-wired base, either a flush mount or surface mount option are available. I spent a considerable amount of time fitting these up before committing to a position on my sail panels. Despite that, the assembly process had more than its fair share of profanity sprinkled moments. I wired the surface mount upper base by installing the included wiring with terminal clips. I then attempted to install the terminal base to the mounting base using the provided machine screw. WRONG! The stiffness of the wiring and terminal clips made assembly impossible. I had to gently bend each terminal out of the way of the mounting base screw boss. Now it was time to "twist" in the tweeters to the upper base. (yes, it is convoluted). Unfortunately the fit between the tweeter and upper mounting base is so tight I had to twist and persuade them with an uncomfortably high amount of force. The bar across the front of the tweeter actually doubles as an install tool. I was literally a hair away from breaking something and the profanity level would have gone from sprinkle to downpour. Now it was time to reinstall the grill. You bet- extremely tight and difficult. 
Had I known all this in advance I could have hacked them up DIY style and duplicated the install with far less headache. 
Regardless, the tweeters are rated A+ in smooth detailed on-axis sound quality in the finest tradition of more costly drivers. They are a breath of fresh "air" from the harsh metallic sound of the old inverted domes and added just the right amount of detail to my 3-way front stage. 
Install hardware, mounting design and assembly are a complete failure however, as are the included instructions. I know this would not stop most of the DIY community and it shouldn't. Enjoy them before they are history.


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## 6262ms3 (Feb 27, 2008)

Interesting, I've been contemplating going semi-active 3-way but have been too lazy to figure out passive x-over and level matching of the mid-tweet. Sounds like this kit paired with some TC9 wide-banders would complement my existing H-Audio Ebony's for warm n' smooth nirvana. Thanks for sharing this!


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## avanti1960 (Sep 24, 2011)

6262ms3 said:


> Interesting, I've been contemplating going semi-active 3-way but have been too lazy to figure out passive x-over and level matching of the mid-tweet. Sounds like this kit paired with some TC9 wide-banders would complement my existing H-Audio Ebony's for warm n' smooth nirvana. Thanks for sharing this!


I bought this set just for the crossovers to use my Focal tweeters as a semi active 3-way! 
When I got tired of the Focal sound I researched the Boston SR60 components that use these tweeters and thought what the heck I'll pop in the Boston Tweeters. The Focals will soon be for sale.


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## avanti1960 (Sep 24, 2011)

update 8/27/2012. day three of listening to these and going through my reference program material- they continue to impress. today i played rush "snakes and arrows" and the acoustic guitars, wood percussion and drum cymbals have not ever sounded as good in my car. realistic sounding is a term i would describe them as- they sound more real than any other tweeter i have used since my car's upgrade odyssey beginning last september- also noise free- no noise, no hiss, no distortion no harshness and on axis too- even at high volume. the focals would spit and hiss even off axis. the focals were overdone on drum cymbals too- they would linger like spray paint hiss- sibilance i guess. 
i should have gone with boston acoustics tweeters much sooner- they have never let me down in the past. too bad they are out of business.


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## spydertune (Sep 9, 2005)

avanti1960 said:


> i should have gone with boston acoustics tweeters much sooner- they have never let me down in the past. too bad they are out of business.


You could have made a difference man.


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## avanti1960 (Sep 24, 2011)

Update 9/3/12
After some really extended listening time these are still extremely sweet tweeters and there are zero issues requiring any adjustment or tuning out. 

The ability to run these nearly on-axis leads to a big improvement in imaging and focus. 

With my old tweeters they were too bright to run anywhere near on axis- and therefore they were basically aiming across the dash at each other with just a touch of rearward angle back. This must have led to an over abundance of reflected sound off the door glass adding to the shifting characteristics of the high frequency image. 

Aiming more on axis seems to greatly reduce the reflections and puts the drirct response right on the sweet spot. All you need is a softer yet detailed tweeter. 
I don't see the need to ever again have a tweeter that has to be mounted off axis to make them bearable.


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## GavGT (Sep 5, 2011)

Nice write up! Interesting as i also have the L3SE in a 2 way setup at the moment. I built sail panel pods on axis for my mids in an attempt to eek as much detail and range out of them as possible but i've ended up with the drivers side being too close to the side window and suffering a few reflection issues including a loss of 17k+ sparkle. I've just purchased 2nd hand a pair of Hertz ribbon super tweeters that come with a 10k 18db passive crossover and -2 to +2 attenuation. I'm planning to mount them on axis just above the sails in the a-pillar. I hope they are as succesfull for me as the Bostons are for you as i really want to stick with the L3SE and use almost its full bandwidth. I just managed to take the EMMA experienced 4000 title in the UK with the L3SE and imagine midbass combo so i'm pretty sure i should stick with them for the time being and add the tweeters.

Gav


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## james2266 (Sep 24, 2009)

I see I am not the only one in stereo flux with a Rav4. Didn't you have Scanspeak tweeters before or am I confusing with someone else? You like the Boston's better than that in that case? I would be really interested in hearing what you thought of the Scan tweet (if that was you). Unfortunately for me, I fried my midbass amp and am waiting for its replacement. I bought it yesterday. I figured I might as well get a better one so I will finally get to try out some Mosconi power. Really looking forward to hearing what that brings. 

Oh, and BTW, I think it was you I was talking about larger midbasses with in this vehicle. Well, you can put in an 8 inch midbass I think. I cut out the baffle for the one I am planning on and lined it up with the inner door panel. I was shocked that it sat almost 100% completely flat. I then tried it on the backside of the door card and same thing. I honestly think that I might even be able to get a 1 inch thick baffle in there possibly. When I recoup some money I will probably attempt this. Also, the beauty part, the ring I cut lined up perfectly with the factory mount holes still. I figure if I counter sink them I should be able to use them. Baffle outer diameter was 225 mm BTW if you are curious. Just figured you might want to know this info. I will keep you informed if I do end up doing this and what my experience was.


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## avanti1960 (Sep 24, 2011)

GavGT said:


> Nice write up! Interesting as i also have the L3SE in a 2 way setup at the moment. I built sail panel pods on axis for my mids in an attempt to eek as much detail and range out of them as possible but i've ended up with the drivers side being too close to the side window and suffering a few reflection issues including a loss of 17k+ sparkle. I've just purchased 2nd hand a pair of Hertz ribbon super tweeters that come with a 10k 18db passive crossover and -2 to +2 attenuation. I'm planning to mount them on axis just above the sails in the a-pillar. I hope they are as succesfull for me as the Bostons are for you as i really want to stick with the L3SE and use almost its full bandwidth. I just managed to take the EMMA experienced 4000 title in the UK with the L3SE and imagine midbass combo so i'm pretty sure i should stick with them for the time being and add the tweeters.
> 
> Gav


gav, congrats on the EMMA victory! 
i really want to attend a competition just to hear how good the best can sound. good luck with the ribbon tweeters- let us know how they work out.


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## james2266 (Sep 24, 2009)

I second this 100% and in a couple weeks here I will go to my first competition. It is in Canada still so I am a little skeptical. I really hope that there are a few cars at least worth listening to. It is about a 6 hour drive each way from me or so.


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## avanti1960 (Sep 24, 2011)

james2266 said:


> I see I am not the only one in stereo flux with a Rav4. Didn't you have Scanspeak tweeters before or am I confusing with someone else? You like the Boston's better than that in that case? I would be really interested in hearing what you thought of the Scan tweet (if that was you). Unfortunately for me, I fried my midbass amp and am waiting for its replacement. I bought it yesterday. I figured I might as well get a better one so I will finally get to try out some Mosconi power. Really looking forward to hearing what that brings.
> 
> Oh, and BTW, I think it was you I was talking about larger midbasses with in this vehicle. Well, you can put in an 8 inch midbass I think. I cut out the baffle for the one I am planning on and lined it up with the inner door panel. I was shocked that it sat almost 100% completely flat. I then tried it on the backside of the door card and same thing. I honestly think that I might even be able to get a 1 inch thick baffle in there possibly. When I recoup some money I will probably attempt this. Also, the beauty part, the ring I cut lined up perfectly with the factory mount holes still. I figure if I counter sink them I should be able to use them. Baffle outer diameter was 225 mm BTW if you are curious. Just figured you might want to know this info. I will keep you informed if I do end up doing this and what my experience was.


james, post some pics when you get the 8's installed- nice work. 
and yes, i am still in flux too! good luck with the mosconi amp- i heard one and it sounded very loud and very clean. 

yes, i did have the scanspeak tweeters installed- they sounded really nice but were not able to play low without any quality. i wanted to have he vocal range up high and therefore the HAT mid/widebands in the upper door where the scanspeaks used to be. unfortunately the scans would not fit on the sail panels without much fab work but the bostons do and sound great on axis. they are running above 8K so they aren't being asked to do too much. 

in my latest effort to improve low end bass i am going to install a new scanspeak sub to replace the JL. 
my car (and likely yours) does not show typical "cabin gain" that extends bass below the normal subwoofer peak or F3. You design your sub to start rolling off at the theoretical cabin gain frequency, e.g. 50 Hz or so. unfortunately with the RAV, there appears to be no cabin gain so the bass just drops like a rock below 50Hz. it's supposed to be flat to 20Hz because of cabin gain! 
So i bought a new sub after much online "modeling" for the lowest F3 possible in the 1.4cuft enclosure I have.
The scan sub has an Fs of 17Hz! It will lower the bass rolloff frequency from 50Hz down to 37Hz or so. 

we'll see how it goes and sounds in a review to be posted soon. take care.


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## james2266 (Sep 24, 2009)

Oh, please, do let me know how that goes. Which Scan sub are you going with anyways? The exact model would be needed as it is really tough to know which driver when it comes to Scan drivers. There are many that have that low fs so I hope it does work out for you. I don't think I totally agree with you on your assessment of the cabin gain of our vehicle. I think it is there like all vehicles but there just seems to be a problem in the 60 Hz or so frequency spot unfortunately. My Ultimo does seem to do well right down to 20 Hz with no eq down there at all. Then again the Ultimo is supposed to play very low very well. I am going to try to get that dip covered with midbass. I hope we are both successful if we are both going at it from different directions.


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## avanti1960 (Sep 24, 2011)

james2266 said:


> Oh, please, do let me know how that goes. Which Scan sub are you going with anyways? The exact model would be needed as it is really tough to know which driver when it comes to Scan drivers. There are many that have that low fs so I hope it does work out for you. I don't think I totally agree with you on your assessment of the cabin gain of our vehicle. I think it is there like all vehicles but there just seems to be a problem in the 60 Hz or so frequency spot unfortunately. My Ultimo does seem to do well right down to 20 Hz with no eq down there at all. Then again the Ultimo is supposed to play very low very well. I am going to try to get that dip covered with midbass. I hope we are both successful if we are both going at it from different directions.


this is the scan sub-

Madisound Speaker Store 
ready to install in 5,4,3,2,1....


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## edouble101 (Dec 9, 2010)

I am thinking about running a set of these tweeters active.

Do you know if the tweeters t/s parameters are available?


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## KBT2011 (Dec 29, 2011)

Have a pair in my F150, and LOVE them. Paired with the SR50's that certainly lack in midbass, considering replacing them. BTW, I second that they are an absolute pain to put in the mounting cups and put the grill back on, I was certain I was going to break mine, in fact I did and I've replaced them since lol.


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## avanti1960 (Sep 24, 2011)

edouble101 said:


> I am thinking about running a set of these tweeters active.
> 
> Do you know if the tweeters t/s parameters are available?


Haven't been able to find them. I say at 85 bucks a pair you have nothing to lose. They are the best sounding tweeter I have used- seriously.


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## avanti1960 (Sep 24, 2011)

KBT2011 said:


> Have a pair in my F150, and LOVE them. Paired with the SR50's that certainly lack in midbass, considering replacing them. BTW, I second that they are an absolute pain to put in the mounting cups and put the grill back on, I was certain I was going to break mine, in fact I did and I've replaced them since lol.


Looks great! Did you try them on axis? They are smooth enough to run them that way and it improves the imaging / avoids reflections. 

Mine are sounding better and better as time goes on. Velvety smooth yet very detailed.


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## edouble101 (Dec 9, 2010)

avanti1960 said:


> Haven't been able to find them. I say at 85 bucks a pair you have nothing to lose. They are the best sounding tweeter I have used- seriously.


I bought a set. Think they can handle a 4-5k xover @ 12db on 30wrms?


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## KBT2011 (Dec 29, 2011)

avanti1960 said:


> Looks great! Did you try them on axis? They are smooth enough to run them that way and it improves the imaging / avoids reflections.
> 
> Mine are sounding better and better as time goes on. Velvety smooth yet very detailed.


I have not tried them on axis unfortunately. Time is limited for me right now with work and school. I've had them running since late April and I can tell you these things sound incredible through and through.


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## avanti1960 (Sep 24, 2011)

edouble101 said:


> I bought a set. Think they can handle a 4-5k xover @ 12db on 30wrms?


Easily. These come with the Boson SR60 component set which are rated for 65W RMS / 180 Watts Peak. 

Good luck!


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## 6262ms3 (Feb 27, 2008)

Lol, well I pulled the trigger on these. I think I'm going to pair them with scan-speak disco 10F mids. One question for you avanti1960, did you put inductors on your mids to low-pass them under the tweeters or are you just letting them roll-off naturally?


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## avanti1960 (Sep 24, 2011)

6262ms3 said:


> Lol, well I pulled the trigger on these. I think I'm going to pair them with scan-speak disco 10F mids. One question for you avanti1960, did you put inductors on your mids to low-pass them under the tweeters or are you just letting them roll-off naturally?


congrats, these are great tweeters! and yes I let the L3SEs roll off naturally because they can be. I looked at the plot of your scan mids and hope you don't see breakup at 10khz or so- or if they are off axis they should be beaming by then anyway because they are 4" drivers. just check after you install and tune them, you should be OK. good luck and let us know how you like them.


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## WannaBBurly (Dec 20, 2009)

Any other comments about off-axis listening? Also, if I was running them active, the 8-ohm impedance would effectively halve whatever power I was feeding them at 4 ohms, right?

Any idea how low they can play cleanly in a 2-way setup? The FR says 8k but I'm assuming that's due to the passive.


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## avanti1960 (Sep 24, 2011)

WannaBBurly said:


> Any other comments about off-axis listening? Also, if I was running them active, the 8-ohm impedance would effectively halve whatever power I was feeding them at 4 ohms, right?
> 
> Any idea how low they can play cleanly in a 2-way setup? The FR says 8k but I'm assuming that's due to the passive.


the poster above with the F150 runs them off axis. mine are not but I believe they would work well. 
with the 8 ohm impedance they are still plenty sensitive @ 90 DB 1watt meter.
yes, the listed low end FR of this set is dictated by the passives. they are sold here as an imagining add-on system but these tweeters come with the Boston SR component sets so they are capable blending in a two way system. 
just today I was enjoying how realistic and near perfect drum cymbals sounded. 
I was swapping tweeters frequently for several months but these have stayed in my car and are the survivors.


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## stylngle2003 (Nov 2, 2012)

Debating picking a set of these up to replace a (now blown) pair of 3/4" tweeters from my Boston S60 component set. 

Think they will blend OK with the 6.5 mids? I'm in favor of putting in a larger Kortec tweeter to gain some upper midrange (6K+) clarity and precision.


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## chithead (Mar 19, 2008)

Nice review. I am debating on a set of the SR60 comps, and look forward to hearing them.


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## avanti1960 (Sep 24, 2011)

chithead said:


> Nice review. I am debating on a set of the SR60 comps, and look forward to hearing them.


thanks- be careful about the comps though, the reviews mention less than satisfactory bass output when compared to the competition. i have personally never heard them.


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## chithead (Mar 19, 2008)

avanti1960 said:


> be careful about the comps though, the reviews mention less than satisfactory bass output when compared to the competition.


I am hoping a pair of G1 subwoofers can compensate for that


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## avanti1960 (Sep 24, 2011)

stylngle2003 said:


> Debating picking a set of these up to replace a (now blown) pair of 3/4" tweeters from my Boston S60 component set.
> 
> Think they will blend OK with the 6.5 mids? I'm in favor of putting in a larger Kortec tweeter to gain some upper midrange (6K+) clarity and precision.


absolutely they will blend. again, these tweeters are also packaged with the Boston SR60 and SR50 component sets.


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## avanti1960 (Sep 24, 2011)

update 12/16/2012

after nearly (4) months of listening to these tweeters- they are still in the car! which is a record. 
i have recently "revived" my interest in jazz recordings since i organized my CD collection. these tweeters shine in their reproduction of jazz cymbals and percussion. cymbals sound outstanding. not perfect, not 100% identical to the live sound- but very nice and real. they don't sound like spray paint, they don't sound sibilant or tinney, but rather have a great blend of detail and accuracy without harshness or false coloration. 
they will reporduce a loud single cymbal "hit" that will reach out and stun you. sharp, detailed, easy to pinpoint, striking, loud without strain. 100% satisfied.


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## JVD240 (Sep 7, 2009)

Anyone know how low you can cross these?

I'm thinking of running them active in a two way setup until I figure out my midrange setup.


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## avanti1960 (Sep 24, 2011)

JVD240 said:


> Anyone know how low you can cross these?
> 
> I'm thinking of running them active in a two way setup until I figure out my midrange setup.


while i haven't been able to find the Boston specs on these tweeters, a random sampling of available 1" textile dome tweeters on parts express show Fs values in the range of 1300Hz, 1500Hz and 1520Hz for example. Rule of thumb is crossover at 2X Fs, which is 2600 to 3040 Hz for these particuar drivers. You should be OK with a similar starting point for the Boston tweeters- adjusting as needed for what sounds best in your car.


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## JVD240 (Sep 7, 2009)

avanti1960 said:


> while i haven't been able to find the Boston specs on these tweeters, a random sampling of available 1" textile dome tweeters on parts express show Fs values in the range of 1300Hz, 1500Hz and 1520Hz for example. Rule of thumb is crossover at 2X Fs, which is 2600 to 3040 Hz for these particuar drivers. You should be OK with a similar starting point for the Boston tweeters- adjusting as needed for what sounds best in your car.


Cool. I was thinking something along those lines. 3-4k

I'll report back once they're in. Switching from XT25's...


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## subwoofery (Nov 9, 2008)

JVD240 said:


> Cool. I was thinking something along those lines. 3-4k
> 
> I'll report back once they're in. Switching from XT25's...


Taking your XT25 out? What's wrong with your tweeter? 

Kelvin


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## JVD240 (Sep 7, 2009)

subwoofery said:


> Taking your XT25 out? What's wrong with your tweeter?
> 
> Kelvin


There's nothing wrong with them.

I'm just swapping because it's difficult for me to mount completely on axis in my current configuration. I'm going to keep them for now. Next step is to pick some mid-ranges and fab some dash pods. I just wouldn't mind giving these Bostons a try.


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